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Credit: Lawrence Berkeley National Laboratory
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Interview of Carl Haber by David Zierler on April 13, 2021,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Interview with Carl Haber, Senior Staff Scientist at Lawrence Berkeley National Laboratory. Haber explains where his research fits within the broader matrix of the Lab, and he describes the challenges with remote work during the pandemic. He recounts his childhood in Queens, NY, and his early fascination with the Space Race. Haber describes his undergraduate work at Columbia, where he became interested in experimental physics and where he worked in Madame Wu’s group. He explains his decision to stay at Columbia for graduate school, his work targeting neutrinos at Fermilab, and a formative visit to SLAC. Haber discusses his postdoctoral research at the Tevatron collider and some of the technical challenges in building calorimeter devices. He describes the origins of CDF, and the focused interest on CERN for collider detectors, and he shares how he felt when the Higgs was discovered. Haber describes his entrée into the physics of audio recordings, and how he sees this work as part of his research agenda. At the end of the interview, Haber explains why he can’t conceive of a better place than Berkeley to pursue a career in physics.
Okay. This is David Zierler, Oral Historian for the American Institute of Physics. It is April 13th, 2021. I'm so happy to be here with Dr. Carl Haber. Carl, great to see you. Thank you for joining me.
It's a pleasure.
To start, would you please tell me your title and institutional affiliation?
I'm a Senior Scientist in the Physics Division of Lawrence Berkeley National Laboratory.
Now, the term Senior Scientist, what does that designate, as national labs have some level of correlation to academic appointments?
I would say it's roughly equivalent to a full tenured professor.
How long have you been in that role?
I think since around 1995.
Carl, a question we're all dealing with these days: how has your science and collaboration been affected, positively or negatively, in this year plus in the pandemic in remote work?
Well, it's an interesting question. In fact, I just finished participating in a study group that the Laboratory did remotely with some kind of consulting firm to try and evaluate how the working conditions affected people, and to try and see if they could learn from that in terms of possible changes going forward, post-pandemic. So, I'm a physicist, and I'm a part of one of these really large collaborations that is based at CERN, in Geneva. So, there are dozens of institutions all over the world that work together on these projects. Typically, we have meetings almost every day of some sort which are already being done remotely anyway, because we have people in England, and people in Italy, or whatever. So, that aspect was quite normal for us anyway. I mean, I still have a meeting at 7 o'clock in the morning, or 5 o'clock in the morning, or whatever it is. So, the international collaborative part, at least, the day-to-day, that hasn't been affected in a big way. We typically would travel multiple times a year to sub-meetings, or larger meetings, either at CERN or one of the other institutions in the US or aboard. That's been totally shut down. That has not occurred at all since March of 2020. So, in place of that, we have more remote meetings. The remote discussion process definitely suffers from what would happen during coffee and during informal discussion. So, the coffee and the informal discussions at places like CERN is kind of the lubrication that keeps the gears moving, and it's a pretty important aspect. So, that has been truncated, for sure. At the Lab, the normal day-to-day discussions with people, the interactions, that's been harder to do. They have let about 15-20% of the people come on-site, and I'm in that category. So, the physical hands-on work, for the most part, I've been able to keep that going. But anything with students, mentoring, training people, that's been much harder. Other laboratories have had more severe lockdown circumstances than ours, so yeah, it's definitely taken a toll on progress. It's overall been harder. I would say, for me, personally, it was sort of as good as could be expected under the circumstances, but you can definitely see the effect all over the place.
To what extent is remote data analysis and computer simulation, the kind of things where you really don't need to be physically present in the laboratory, to what extent are these technologies relevant and made the pandemic not as harmful as it may have otherwise been on your research agenda?
What was the last thing you said? On my --
Oh, research agenda. Well, certainly, anything you can do with computing, simulations, data analysis, people have been continuing that work remotely. For example, our group, you can sort of roughly break it into people that build and test things, and people that analyze data. So, the data analysis people have been chugging away at their work in their home offices. I haven't seen them in a year, okay? So, that whole interaction between the two sides of our enterprise has been pretty much severed, in a way. I guess, they're making progress. When I hear them giving presentations, they're clearly doing stuff, but there's very little cohesion between the entire group because of that. But yeah, I mean, look, the typical thing is some student goes to CERN for two years, and then comes back to Berkeley, or wherever their institution is, and does their data analysis remotely. I mean, that's always been the case. So, the possibility of doing remote data analysis is not a pandemic issue. It's more the day-to-day local interaction, I think, that suffers.
Carl, to give a sense of where your group is overall at the Lab, let me understand where you fit in in the overall organization.
Okay, so the Laboratory is obviously a huge entity. It had its foundations, whatever, 90 years ago, in what we would today call “high energy physics”, or high energy for its time, right? The machines that were being built in that era were kind of low energy nuclear physics kind of level things, from today’s perspective. But, okay, it was the frontier at the time. Today, the Laboratory, I think, technically is considered a Basic Energy Sciences lab. It's part of the BES wing of the Office of Science. So, most of what goes on at the Laboratory falls under BES, or other non-high energy physics areas. So, high energy physics is, I don't know, 10% or less of the Laboratory. So, I'm within that activity. The bigger activities are around materials, photon science, electron microscopy, nano science, even biology. Those are the really big growth areas, if you like, at the Lab. But high energy physics is the Lab's legacy, and that's what we're part of. So, I work in the physics division and I've been there for about 35 years. So, when I came, pretty much everybody was doing some kind of accelerator based high energy physics, over at SLAC, or at Fermilab, or wherever. Now, the Division is probably equally split between people doing cosmological physics using telescopes to analyze fundamental aspects of the universe, people doing accelerator-based stuff like us, and then people involved in searching for dark matter—or things that involve essentially going deep underground with some large detector and looking for a very rare signal that's naturally occurring. There's no accelerator involved. So, the group that I'm in, is called the ATLAS group. ATLAS is a big international experiment based at CERN; A Toroidal LHC ApparatuS, is what it stands for. I have been in that group since about 1994, or 1995, when the Supercollider was terminated. A lot of people at Berkeley Lab, at that time, were planning on doing experiments at the Supercollider. Then, when it was terminated, the group kind of, en masse, joined with ATLAS. Concurrent with that shift, and also prior to it, I was working on an experiment called CDF, or the Collider Detector at Fermilab, which I joined in 1985. So, now the ATLAS group is the remnants of the CDF group, the remnants of the Supercollider group, and then all sorts of new people who weren't even born when all those transitions happened. So, I'm one of, I don't know, a handful of senior scientists in the group. The group is about 40 or 45 people: students, post-docs, scientists, senior scientists, divisional fellow, and so forth. We work on a whole diverse range of activities within ATLAS, from data analysis through designing and building new parts of ATLAS that will be installed in the future. My personal involvement is nearly 100% in the development and construction of new hardware, new detector systems that will go into a future upgrade of ATLAS that will occur in the latter part of this decade, hopefully.
Carl, let's take it all the way back to the beginning. Let's start first with your parents. Tell me a little bit about them and where they're from.
Okay. So, everyone is from New York City. My parents were both born in New York City. My father is like 93, and my mother is 90, and they're still living in the house that we all lived in. My mother was born in the Bronx; my father was born in Queens, and I grew up in Queens. Their parents were all immigrants who came to the United States from Eastern Europe in and around 1912, sort of 1915, that kind of timeframe, in that big migration through Ellis Island, that whole story. You know, they both came from reasonably large families. They were both, I think, probably the only ones that went to college in their families. Grandparents couldn't read or write; they were not literate in that sense. They worked in trades, and things like that. They made a living, and it was a big, important sense of their purpose and their pride, obviously, for their children and their grandchildren to participate in these opportunities that education would get you.
Where did your parents meet?
Where did they meet? I think they met at one of these hotels in the Catskills, or in northern New York somewhere. I think my mother was working as a waitress, and my dad might have been a guest there, or vice versa. I don't really remember.
This is a common New York story, of course.
Yes, yes, but they both definitely worked summers in a variety of these places. Green Mansions; Totem Lodge. I've heard the names of these places. There were a lot of such places in the past; not so much anymore. But yeah, they met at one of these venues.
What were their professions?
They're both retired now. My father was an attorney in an essentially private practice, a kind of one man show. He had an office in lower Manhattan in the Financial District. He did a lot of defense work on behalf of certain insurance companies that would hire him to defend a store, or a doctor, or a hotel, when there was an injury, or that sort of a thing. In fact, one of his big clients—at least when I was growing up—was a hotel that no longer exists, but was called The Concord, which I think was supposed to be the biggest of those Catskill hotels. He defended them when they were sued; somebody slipped and fell. There was an accident that occurred around a boxing match. There were horseback riding accidents. Things of that sort. And people would sue for what was a lot of money in those days, and he would defend the hotel. And my mother was a schoolteacher in the New York City public school system. She taught school for a bunch of years, and then I think she stopped for a while when her children were young, and then she went back. She eventually started teaching education at the college level in the New York City University system, or the community college system. She got a PhD in education, so she did that for a while, and then she went back to classroom teaching until the end of her career. She did a lot of early childhood stuff around reading. But I think at the very end she was a classroom teacher in a New York City public school.
What neighborhood did you grow up in?
Well, so, on the envelope it would say Flushing, New York. The sub-domain is called Kew Gardens Hills, but it's basically where if you take the LIE, the Grand Central, the Van Wyck, Union Turnpike, and the Interborough, and you look at where they all intersect, there's like a little piece of land. So, you've got highways-- basically, everywhere you look there are highways. It's very, very close to the site of the 1964-'65 World's Fair. So, you could essentially walk to the World's Fair from here. I remember, as a little boy, watching them build it and then take it down.
From Eastern Europe to Kew Gardens, all of the cultural markers are there, but you haven't specified. I assume you come from Jewish heritage.
Yes, yes, we're Ashkenazi Jews.
Growing up, was your family Jewishly connected at all? Were you members of a synagogue?
Yes, we were members of a synagogue. I was Bar Mitzvah in the local synagogue. We were Conservative, and we were not going to synagogue every Saturday, but certainly the family had a strong cultural identity, in terms of celebrations and all of that. And you know, there was observance around holidays, obviously, and High Holidays, and things of that sort, but not like every Saturday.
Did your parents retain any Yiddish from their parents?
Yeah, definitely. In fact, one of the things they've done to busy themselves during the pandemic has been to do a lot of memory-based story writing. They've been taking some classes online, writing classes, and my mother has been using her Yiddish in some of those stories, talking about her mother. So, yeah, in fact, my mother spoke Yiddish. She learned it from her parents. It was a kind of way of finding out what they were saying. My father also spoke Yiddish. They would even speak Yiddish to each other sometimes if they didn't want us to know what they were saying. We had a cousin who emigrated from-- he was a Holocaust survivor who made his way to Israel, and then eventually moved to Canada. At some point, he came here, and stayed with us for -- it feels like a week or two, and my father spoke to him in Yiddish. This was when I was a teenager. And I think he really enjoyed that experience of kind of tuning up his Yiddish in conversation with his cousin.
Carl, when did you start to get interested in science?
Okay, so, I was born in 1958, and then I went to grade school, and so forth, through the 1960s. Of course, the whole space exploration thing with the Mercury and the Gemini missions, and the Apollo missions, that was kind of front and center for kids of my age. I remember every time there was a rocket launch, they would roll this big television into our classroom, and we would stop everything and just watch the rocket take off. You'd see it kind of going-- I never understood why it always looked like it was going flat, but somehow that was the way they filmed it. And then we would have to write detailed logbook reports everyday about the mission, and all of that. I mean, nobody does that anymore. And then we’d also get these books – they would give us these books that came from this organization called the Science Service that would explain to you about work that was going on in atomic energy, or something, and there would be these sheets of pictures that were perforated, that you had to tear out and moisten in place as part of understanding the narrative. I remember there was a whole thing about Glenn Seaborg, and Berkeley, and the cyclotron, and all of that. I had no idea that I’d eventually work in the building next to where he worked.
But it planted a seed, perhaps.
Yeah, oh, definitely. And computers were coming up, and electronics. I had a cousin who was maybe five years older than me, who was just a brilliant kid at anything electrical. He kind of took me under his wing and I kind of emulated him in terms of wanting to be able to build stuff and make stuff work. And then, of course, just Einstein, and figures like that were so famous and such heroes to people of my generation, that it was very alluring. It was everywhere. You felt it everywhere. And I think my parents had a lot of friends who were in academia, so there was a respect for research. (My parents were old friends with Herman Winick who, at that time worked at Harvard in physics, and then moved to SLAC. I remember going to visit the Winicks in Massachusetts and being taken to see the “atom smasher”.) I also very clearly remember my father talking about J. Robert Oppenheimer, who was such a compelling mid-century figure, and taking me to see, In the Matter of J. Robert Oppenheimer, which as a dramatization of his security hearings. That made a big impression on me. So, there was a lot of stuff around science that just kind of saturated my childhood. But interestingly, there was a very, very strong parallel thing going on around the visual arts. So, painting and drawing and all of that was probably just as important to me growing up, and I got a lot of that from my mother. So, there was a—I wouldn't say a tension, but as a teenager, I kind of felt both of those forces pulling me in different directions.
Carl, did you go to public schools throughout?
Yeah. So, just like everyone, I was a New York City public school student. I went to the local elementary school, the local junior high, and also the local high school. I did get accepted at Bronx High School of Science, but it would have been like a 90-minute commute, and we just decided that-- it just didn't seem like that was a good tradeoff. I don't know, maybe-- I don't know how that would have turned out, because I would have obviously been put in a much more competitive environment early on.
What about Stuyvesant or Brooklyn Tech? Same challenges?
Well, probably less so from a commute perspective. In fact, my sister went to Stuyvesant, and my best friend went to Stuyvesant, who just lived a few blocks away. So, Stuyvesant was definitely an easier commute, but somehow-- and I don't think this was correct, but I think we viewed Bronx Science as kind of the science school, and Stuyvesant as more of a broad academic school. In fact, my sister and my friend, neither of them went into the sciences for their careers. So, I think Bronx Science was more well identified as the science school. But all I'm saying is if I had gone there, who knows? I might have felt like my capabilities didn't match some of these other kids, and maybe I would have been put off. I don't know. Who knows?
Between family economics, geographic considerations, and your grades, what kind of schools were in reach for you for college?
So, for college, I applied to one Ivy-- no, maybe two. Okay, so first of all, I should say that by the time I was going to apply for college, I had decided that somehow the best balance between the scientific interest and the more-- I don't want to say creative, but the notion of making things, was going to be engineering. I didn't really actually have any idea what these things really were. So, I applied to engineering schools, and I thought that I would do what was called bioengineering at that time. Bioengineering, I think, had a very different meaning than it means today. I know bioengineers at Berkeley, and they work on basically using genetics to manipulate cells to do things they want them to do, to make alcohol for example, or whatever. Or they do things around manipulating DNA, or -- it's very much embodied in a microbiological sort of context. But what I thought bioengineering was, could be designing prosthetic devices, for example. Interfacing between the nerves and an arm for someone who had an amputation. Something like that. That seemed to me to be a good balance between science, human values, and making things. So, I applied to Cornell and Columbia, those two Ivies a whole bunch of state schools, and then Rochester and Tufts, I think. Sort of northeast, good schools, and had good engineering. You know, I wasn't the top student in my school, but I had all the good grades and all the good scores that in those days would have made me a reasonable candidate. Today, probably I wouldn't have gotten into any of those schools.
So, clearly, as you say it, it was not physics. You were not laser focused on physics at that point.
No, not at that point. I didn't even really know what physicists were really doing. That all came, pretty much-- long story short, I'm pretty sure I got into all those schools. I might not have gotten into some of them. Interesting, I did want to apply to Berkeley, but I was told, “No way. That place is just a hotbed of radicalism, and you are not going there.” You know, this was like Patty Hearst time, and all of that. “No way are you going there.”
So, it wasn't just geography. The same would not have been said of a Stanford or a Caltech.
No, probably not, or Chicago. It didn't occur to me to apply to Stanford or Caltech. Caltech might have occurred to me, but no, I think I wanted to apply to a school that had a broad student body. I didn't apply to MIT, for example. I think I wanted to be in a broader environment. Even these schools were not so expensive in those days. I have two college age children right now, and it's really different. So, I'm pretty sure I got into most of those schools. I remember some of the discussion where I kind of wanted to go to Boston, and they were like, “Well, you got into Columbia.” I really liked New York City, so I said, "Okay, fine. I'll go to Columbia.” And that turned out to be a really good choice.
Close to home, as well.
Yeah, but I moved up there. I lived in Morningside Heights, and I ended up staying there for graduate school as well.
What was your initial major there?
So, Columbia, for undergrads, there was the College, and there was the School of Engineering and Applied Science. They were kind of together, but they had different curriculum. It was an overlap, but I was in the School of Engineering and Applied Science. Here's the thing. Columbia, unlike any other school, except maybe the University of Chicago, and a couple of smaller liberal arts schools, has a very strong core curriculum. So, there's a whole suite of courses that every single Columbia student has to take. Loosely, it's a Great Books, western civ sort of thing. Even engineering students had to take that, and still do. Their whole thing was, 1918, they said, “What are we going to do to prevent another war like this that could destroy western civilization? Well, we better have everybody understand why western civilization is worth keeping.” So, they came up with this Great Books curriculum, so called Core. They call it the Core, and as an engineering student, I had to take those classes, just like all of the students in the College. So, every single student is taking the same class. There are small sections and discussions, but everyone is taking the same class, and everyone is reading the same books. So, the person across the hall might not be in your section, but he or she is reading Saint Augustine, basically the same time you are, or Plato, or Machiavelli, and you're talking about all this stuff. Now, there could be a slightly different-- let's say not a concentration, but a slightly different emphasis depending on the field of the teacher. So, the course that I was taking as a freshman was called Contemporary Civilization. That is the western philosophy, political, and philosophical thought part of the Core. This man was writing his PhD thesis on philosophical issues in quantum physics, which is a whole subject that actually is-- you may know about this, but is enjoying a huge renaissance today. Maybe he was a pioneer, I don't know, but he was dealing with issues in the philosophy of science. So, when it came to that period in European history of Newton and Galileo and all of that, we spent a fair amount of time reading some of those texts. And then, he had us read a very famous book called the Structure of Scientific Revolution by Thomas Kuhn. So, this is the book where a big analysis is done of how science changes, how scientific theories are overcome, and grow, and change, and morph, and so forth. So, there was a lot of discussion around the early 20th century, and how relativity and quantum mechanics overtook the classical way of thinking, physically. So, this was fairly new to me, and I just found it extremely interesting and extremely compelling. I struck up a relationship with the teacher where I would come to the office hours, and he would sort of try out some of his ideas from his thesis, I think, or try to tutor me on what the issues were that he was trying to think about. I don't know why he thought that a freshman would be worthy of that, but it was interesting. He really kind of sensitized me to what some of these arguments were. He suggested a book which was called Physical Principles of the Quantum Theory, I think, by Werner Heisenberg. It was Heisenberg's lectures that he gave in the '30’s at the University of Chicago. I could not understand the book in a very deep way, but I read it, and I was starting to glean stuff from that book, and from the discussions with this guy. I was also taking physics, because that was part of the engineering curriculum, as well as chemistry and calculus and so forth. But through that latter half of my freshman year, I just was really getting more and more interested in physics, and particularly, modern physics and quantum mechanics. I was thinking this is something I really want to understand, and I felt like I had an opportunity at that point to understand those things, to learn those things. I was in a place where I could do that. So, I started to entertain the idea of switching out of this engineering track, and seeing if I could shift in physics, but it would have meant transferring out of the Engineering school, and into the College. So, that summer, my cousin, this cousin that I mentioned who was really good at electronics, by that time, he was working in an electronics manufacturing company out in Long Island somewhere, and he got me a job working there. But it was really-- it wasn't a technical job. Basically, I was just working on an assembly line in some way, and it was very-- you know, these hugely hot things that you would pour solder on, and I was burning myself, and all these nasty chemicals. Today, it would probably not be okay, OSHA-wise, what was going on in that factory. I was pouring these weird chemicals to coat circuit boards, and I was feeling dizzy. So, I took a day off, and I went back to Columbia, and I talked to my physics professor because I had had some questions leftover from the course, and I had done some small calculations about accelerators, or something, and I wanted to check those with him. And as I was leaving, I thought, what the heck? And I said, “Do you guys have any need for any students in your lab?” And he goes, “Actually, we are looking for a student,” and he basically offered me a job on the spot to be, essentially, a helper in the lab that summer. So, I quit the job in the factory, and I went to work. So, Columbia, Pupin Hall is the physics building. It's this old building; it's a national landmark. In the basement, there was an old cyclotron, and Enrico Fermi and John Dunning used that machine to measure the energy release in fission. That was the beginning, essentially, of the Manhattan Project. That old cyclotron, the yoke was still there. It was just stuffed with junk, and that room was just a storage room, but in the other rooms in the basement is where this professor had his lab. They were doing low-temperature physics. They were measuring the properties of superfluid helium, close to absolute zero, and they put me to work building circuits from them, doing data entry, and various jobs around the lab. That was it. I mean, I got to hang around with the graduate students, start to learn more about what they were doing, and start to learn the actual hands-on techniques of experimental physics. And then I was like, you know, this is what I want to do.
And the positivity from that experience sort of canceled out any potential career in theory for you. It was always going to be experimentation.
Well, I mean, theory obviously was very enticing, because that was sort of the cool part of modern physics, and I read a lot about theory. But at Columbia, they would tell you that—this is what I recall—if you go to graduate school in Columbia, there will be 20 students in your class, and you're going to sit after the first semester for an exam called the qualifier. The top three students will be invited to do theoretical physics if they want to. That's it. So, I was like, there's no way that's going to be me. I don't know how it was at other schools, but at Columbia, the theorists were so daunting in their stature from the point of view of a student.
Who were the luminary professors when you were an undergraduate? Who was there at that point?
Well, T.D. Lee was, let's say, the leading person in the department. He and C.N. Yang had won the Nobel Prize in the late 1950s for parity violation. So, T.D. Lee was there; Joaquin Luttinger, who was a very important solid-state physicist, was there. Al Mueller, who was one of the leading people in quantum chromodynamics, was there. And then there were people like Gerald Feinberg, Norman Christ, and Richard Friedberg, who had been students of T.D. Lee, so there was a whole department, group of people who had been built up around T.D. Lee. So, these guys were very impressive.
I. I. Rabi, did you have any contact with Rabi?
Well, Rabi was not a theorist. Well, let's say, Rabi would certainly be considered an experimentalist. He was probably in his 80s at that point. He was around the department. You would see him at seminar, at colloquium every Friday, or whenever it was. I think they were on Fridays. So, you'd always see him at colloquium, and you'd see him in the hallways. Then, by the time I was a graduate student, there was a professor who I used to talk to quite a lot, who was a theorist. He taught our quantum mechanics class, Henry Foley. He was quite friendly with Rabi, so sometimes I'd go into Foley's office and Rabi would be there. So, you could actually sit in the same room with Rabi. He'd say things, and you'd record them in your mind. But he wasn't somebody that, as a young student, I had a relationship with. You saw him in action; you heard him ask very provocative questions, and things like that, in seminars. You definitely felt the presence of these people, but I was not going to be a theorist. I just didn't feel like that was--
Who were some of the professors that became a mentor to you as an undergraduate?
Okay, so, the first professor that I worked for was named Bob Guernsey, and he was doing these experiments in low-temperature liquid helium. So, they were trying to study superfluidity. It's amazing to me now, because the techniques they used, and some of the issues that they were studying—like macroscopic quantum effects, quantum vortices, and things like that—are very much related to topics that are really big, both technically and scientifically, in areas of quantum information science and quantum technology, today. But that was a much, much earlier time. So, he was a mentor in the sense of taking me in and placing me in close contact with his graduate students. But then he left Columbia the next year and went to IBM to work on their low-temperature computers, which at that time, didn't pan out, as far as I know. They were thinking they could build superconducting computers using Josephson junctions. Now, of course, quantum computers are using the same low-temperature techniques that were being used in the labs down in the basement. So, he left, but there was another group that was also doing low-temperature experiments down the hallway. But they weren't studying liquid helium; they were studying nuclear physics at low-temperature. The group belonged to Chien-Shiung Wu, who was the woman who actually discovered parity violation after T.D. Lee and C.N. Yang suggested it. She did this famous experiment—Wu, Amber, Hayward, Hoppes, and Hudson—where they used magnetism to orient nuclei at low-temperature, and then study the angular distribution of the decay products and show that parity was violated. So, it was that experiment for which she really should have received the Nobel Prize, that got Lee and Yang the Nobel Prize. So, she was doing these refined nuclear physics experiments, and she had a group around her, and there was a younger professor named Joel Groves. He was the guy who was hands on, doing the experiments. And then they had post-docs and graduate students. So, they basically hired me as soon as the other group disbanded, because I had some of the same skillsets that they needed from students. So, I ended up working for Professor Wu and Professor Groves as an undergraduate, for the rest of the time that I was at Columbia as an undergraduate.
What was Professor Wu like?
She was, I would say, a quite formal person. She was very serious. She was not somebody that you just sort of sat back and listened to stories about. There was definitely a formality, I felt, but there was also, I think, a real warmth about her, and a real humanity that I felt, even as a student. Just some little things that she said, and little remarks that she would make. And there was a group of people around her, like her admins, and the people that supported her operation. You kind of had this sort of family feeling about it, and everybody was very warm and friendly and kind and supportive. So, she definitely cultivated a whole ambiance that I felt very comfortable in. And she would tell stories sometimes, like in meetings. But the meetings were like -- there was a certain time when -- her office was on the 13th floor, she'd come down to the basement and there'd be a meeting, and then she'd go back up. It wasn't like we'd just run up to her office and say, “I was wondering about this thing.” So, she was kind of old school. In later years, after I left Columbia, I crossed paths with her a couple times. Once, she came to Berkeley -- she had been a Berkeley student in the '30s, and she had been a student of Emilio Segrè. She came and gave at talk in Segrè's honor—I think Segrè was still alive. And it was hilarious, some of the things she said, and the stories she told. It was really amazing to watch her pay tribute to her mentor. She told this story about how she had a radioactive source, and somehow he didn't approve of the way she was handling it, and he said to her -- you know, this was like in the ‘30s. He said to her, “Miss Wu, you really need to put that source away when you're done with it. Don't you want to have children someday?” Or something like that. And this was like a talk on an overhead projector, and she took out her next slide, and it was a picture of her grandchildren. And she said, “Look! I have grandchildren. So, you're wrong.” Or something like that. So, I thought that was a very friendly, funny kind of story.
Carl, as a woman operating at her level, did you appreciate what a pathbreaker she was?
I don't remember specifically, but yes, of course, we knew there were very few women in physics, and very few women of her stature. We were aware that she didn't get the Nobel Prize, and why not? She certainly should have.
Did you detect bitterness at all from her on that, if you were able to engage with her on that level?
No, I wouldn't -- no. First of all, that wouldn't have been a level that we would have interacted. But you know, she was extremely distinguished. I mean, she was -- I mean, I remember going up to her office to bring something, and she had just gotten off the phone with the Security of Health Education and Welfare at the time—the Carter Administration, or whatever. She was known in high corridors, and I think she was the first person to win the Wolf Prize, which was the first—now, there are many prizes that emulate the Nobels, and I think she was the first winner of the Wolf Prize. I was there when she won the Wolf Prize, and I remember that was a really big deal.
What was she working on when you first interacted with her?
Right. So, she had kind of, I would say, a relatively sprawling research enterprise. She was one of these people who had a whole bunch of different research directions that were going on almost concurrently, and each one would have a different assistant professor that was running it. So, she had a group of people that were doing muonic atoms. So, the idea there is that you can make an atom with a muon instead of an electron, and because the muon is heavier, its radius brings it in closer, and the spectra of muonic atoms gives you insight into higher order corrections. So, there was kind of fundamental physics around muonic atoms. She was a pioneer of underground experiments, and she was pushing for there to be a big underground physics facility where the cosmic backgrounds would be low, which is, of course, hugely important now. So, she had just finished an experiment looking for double beta decay using selenium foils. Double beta decay is one of the big industries now. Not so much with selenium, but with other potentially double beta decay, unstable isotopes. She had this nuclear orientation area that I was assisting as a student in, studying essentially parity violation in nuclear decays, which gave you a way of measuring certain transition ratios that were interesting for nuclear physics. And then, she was also doing Mössbauer spectroscopy on hemoglobin, because iron is a good atom for Mössbauer spectroscopy. So, you look at the iron, which is in hemoglobin, and you can look at the way the structure of hemoglobin affects the iron. So, they were doing those Mössbauer spectroscopies. There may have even been other things, but she was doing essentially biophysics, nuclear physics, deep underground fundamental symmetries with the double beta decay, and looking at higher order effects through muonic atoms. So, she was really all over the place, doing things that you can even see have derivatives today, in major efforts. And some of her students, like David Hitlin, who became a major figure in American high energy physics at SLAC, was a student of Professor Wu. She had a number of very successful students. So, yeah, she was the real deal.
Did you have a senior thesis?
I don't think so, no. No. In fact, all this work that I did in their labs, it was lab work. It wasn't like I was-- I wasn't doing a measurement. I wasn't doing my own physics. I was building stuff: amplifiers, a detector, a control system, writing code—stuff they needed. I was just helping.
When it was time to think about graduate school, what kind of advice did you get?
Hm. You know, I -- okay, so, all through this period, right? I'm working around these kind of nuclear physics people, but I also have this very strong interest, and this very strong sense that I wanted to do high energy physics, that I wanted to work at basically the large accelerators. That wasn't her area, right? She was using lower energy phenomenon, or very low energy phenomenon to probe fundamental physical systems, which is still very much a big theme in fundamental physics. Low energy, double beta decay, things of this sort. But the frontier, if you like, in my kind of naive mind, was high energy particle physics, where you use the highest energies, and you're looking for the top quark, the W boson-- you know, the new particles, kind of fleshing out the Standard Model. The Standard Model was hugely -- that was the centerpiece at that time.
So, in the mid to late ‘70s, where was the most exciting work being done as far as you could tell? Were you looking at places like SLAC, or Brookhaven, or LBNL?
So, in the late ‘70s, there was important stuff going on at SLAC, at Fermilab, at CERN, Brookhaven, so it would have been working at one of those facilities—the really big thing, and I'm going to get the dates a little wrong, but we were all aware that at CERN they had built the Spp[bar]S Collider with Carlo Rubbia kind of at the head of all this. I remember going to the American Physical Society meeting at the Hilton in New York—I don't remember if I was an undergraduate or a graduate student at that point, because it would have been the late ‘70s or the early ‘80s—I can't remember, because I ended up staying at Columbia.
Well, you would have graduated --
In ‘80, and then I got my PhD in ‘85. Yeah, I don't remember the exact, whether I was still an undergrad-- but anyway, I remember going and hearing Carlo Rubbia give the talk where he announced that they had seen the W particle. I don't know if this was the only announcement, or the first one, but this was like the big announcement in the US. And the idea of working on one of those large high energy physics experiments was very appealing to me. Also, I remember, while I was an undergraduate, Leon Lederman, who was a Columbia professor, they discovered the upsilon, which was the bound state of a B and a B[bar]. So, that was the beginning of B physics. That was discovered at Fermilab. So, I remember learning all about that experiment, and reading about it, and understanding how it was done. So, I wanted to do something in high energy physics.
Was the overall sense at this time, from your perception as an undergraduate, that high energy physics was where the Standard Model would be broken, or was the Standard Model still being built at this point?
Oh, no. The Standard Model-- okay, so there are two things. The theoretical structure that we call the Standard Model was in hand at that time. It was known that there was a Weinberg angle, that there needed to be a Z particle, that there was likely three generations, that there needed to be a Higgs, and all of that. I mean, the books that explain that, you could read them. The important work had been done in the early ‘70s, like Veltman and 't Hooft showing that the Weinberg and Salam theory was renormalizable. The theory itself had been written down in the ‘60s. You know, they had done those experiments to see parity violation in electron scattering at SLAC. So, they already could see that there was some admixture going on between the photon and the Z. So, there was a lot of expectation that the Standard Model would get fleshed out. The numbers would be measured. Because the Standard Model doesn't tell you what the W mass, and what these quantities are. You need to measure the quantities to specify the model, but the structure was all there. So, finding the W and the Z and searching for the Higgs, searching for the top quark, measuring the Weinberg angle, those were-- and the width of the Z, which tells you about how many generations of neutrinos there are-- those were the important measurements that were going to be done at Fermilab, at LEP, at these various machines, at the p[bar]p collider. So, that was all kind of in the air. There was a lot of stuff that people wanted to measure at that time.
What compelled you to stay at Columbia? Why not go to Illinois where you could be close to Fermilab, or Stanford where SLAC is right there?
So, now, I don't remember—it's all fading into post-doc applications versus graduate school. I don't remember where I applied for-- I think I applied to Harvard, because I knew about the p[bar]p experiment and Rubbia was a Harvard professor. I think I applied to Cornell. I can't totally remember where I got in and where I didn't get in, but the thing with Columbia is-- I don't know if they do this today, but at that time, I remember I was just sitting in a physics library, working on some problem set as a senior, and the secretary of the physics department office came in, and she handed me a letter. It wasn't even on a full piece of paper. It was a half-page. It just said, “Dear Mr. Haber, Congratulations on your good work as a physics student at Columbia. This is to let you know that if you decide to go to graduate school at Columbia, you will be admitted. Sincerely,” whatever -- whoever was the chairman. You didn't even have to apply. That was their strategy at that—I don't know what they do now, but their strategy was if they had a student, and that student got a certain level of performance -- grades, I don't know what it was -- I was not A+ on everything, but I think I got an A in some important classes, or something. If they thought that you could be a good student, they just invited you to stay.
So, obviously, they went against the intellectual mold of it's better to go off somewhere else and broaden your horizons.
That was not-- yeah, I mean, I'm very aware of that idea, but over the years, I have met and, in some cases, worked with many people that are older than me who went to Columbia. Many of them were Columbia undergraduate and Columbia graduate students. It was just the way-- it was an idea they had. I don't know if it was good or bad, but these people were pretty successful.
Carl, how much was it inertia-- you were just fine where you were, and how much was it you were specifically excited about staying at Columbia because you had an idea of who you would work with, and what you would do?
Well, so, in my perception, Columbia was one of the really good places to do experimental particle physics. There was this laboratory, which I had spent no time at, up the Hudson in Irvington, New York, called Nevis Labs, and the whole high energy group was based at Nevis. They were doing experiments at Cornell and at Fermilab. So, what happened was during my senior year, a group of physicists from Caltech moved to Columbia, and they were running a very large neutrino physics program at Fermilab. The group moved to Columbia, and the leader of the group was Frank Sciulli. The younger guy, who was an assistant professor at the time, was Mike Shaevitz. And suddenly, there was this big neutrino physics program that had just landed right smack in the middle of the Department, and at that time, there were the first, which turned out to be incorrect, but the first indications that there might be neutrino oscillations. There were inconsistencies in certain neutrino measurements that turned out to not be inconsistencies, once they got fleshed out. Of course, as I'm sure you know, neutrino oscillations got discovered years later, but not because of these problems. But suddenly, there were all these meetings going on about neutrino oscillations and neutrino mass, because there were also inconsistencies around the endpoint of the beta spectrum, and some Russian experiment. Everybody was really excited about neutrino oscillations. And these guys were like, we're going to do a neutrino oscillation experiment at Fermilab. We're going to repurpose a whole bunch of stuff that we already have, and do this kind of almost like guerrilla, commando. We're going to come in and do this experiment really fast. So, I basically got connected with those guys, and I became the one of the first Columbia student to join that group. And Mike Shaevitz was my thesis advisor, and I was his very first student. How did it go? I think even before I finished my coursework, they sent me off to Fermilab to help work on running this experiment, and then came back and finished my coursework. It was all done super-fast. So, I was basically right out of the frying pan, kind of a thing, into this neutrino experiment super-fast. And I actually graduated really fast. They were like, “Don't hang around. Get your PhD and move on.” So, I think it was like four years, or four and a half years from graduation to graduation with these people.
Who were some of the key people you worked with at Fermilab?
Okay, so there was initially -- as a graduate student, you mean?
Yeah, yeah. So, there was this neutrino physics group, and Frank Sciulli was the leader of it, but this run, which was called E701, was specifically targeting neutrino physics -- sorry, neutrino oscillation physics. And this was Mike's experiment. So, Mike was the spokesperson of the experiment, and I worked directly for him. But there was a group of really strong post-docs that had-- sorry, I've got to take a drink here. There was a group of very strong post-docs/young assistant professors that were on that team. It was one of these things where you don't realize until afterwards, but you were with just a really great group of people. And then, when you compare it later to other groups of people, you realize. So, there was Arie Bodek, who was at the University of Rochester. He was amazing. Frank Merritt, who was a young assistant professor at the time at Chicago. Then there were these post-docs, like Wesley Smith, who went on to a very distinguished career at Wisconsin as a particle physicist. In fact, he just won the Panofsky Prize a year or so ago. Mark Oreglia, who ended up at the University of Chicago. Petros Rapidis, who worked for many years at Fermilab, and a guy by the name of David Leventhal, who was an interesting character, who stayed in physics for another, say, ten years, and then he left and became very involved in high performance computing, and then he started making wine. But these were all very strong people, in terms of their scientific personalities and their skills. So, yeah, it was an exciting group of people. I may be forgetting some folks, but it was a very exciting dynamic of people to be working with.
Carl, what were some of the projects that you were working on that were really responsive, to go back to when you were in college, and you had these big ideas about what was exciting in the field?
I'm not quite sure what you're asking.
There's this new frontier in high energy physics, right? As you're in graduate school, and you're living this dream, you're experiencing what you had hoped to accomplish as an undergraduate. Specifically, what were those projects? What were you a part of that was at the frontier of this field?
Okay, yeah. So, the thing is-- the interesting thing about the milieu of particle physics, at least at Fermilab in those days, is it had a very industrial feel to it. You were in these big, kind of dirty halls, with concrete everywhere, and large noises, and heat, and equipment. It looked like a steel mill or something. There were these massive cranes. It wasn't the quiet precision of, let's say, an optics lab or the basement labs in Pupin, or something like that. And it was cold, especially in the winter. So, there was this feeling of almost like frontier, sort of, like, atmosphere to it. You had to trudge your way through mud to then measure something about an elementary particle. Something like that. There was this joke that David Leventhal used to tell people about how there were these different areas in Fermilab: the Muon Lab, the Meson Lab, the Proton Lab, where the different beams would go. And the people that worked in these different labs kind of had different reputations. Like, these people were rowdy, and those people were bookish. I don't know, some made up thing. But he had this story -- I don't know if you're familiar with Fermilab, but there's this huge campus, and at one extreme, there's this little village where everyone lives. There are little houses that they took over from a housing development, so there's this physics village. Then, several miles away are the experimental facilities. And in between are buffalo and bison, big fields full of these animals from the 19th century. So, David used to say, “Two mosquitos that lived in the Village were flying around Fermilab looking for something to eat. They saw there was a buffalo that had been separated from the herd. So, the two mosquitos swooped down, picked up the buffalo, and were flying off with it, because these radioactive mosquitos are really strong. And suddenly it started to rain. They're like, “oh, it's starting to rain. We better go somewhere before we eat this buffalo. Why don't we take it over to the Meson Lab?” And the other said, “are you crazy? The mosquitos over there will take it away from us”.” That was kind of the feeling, you know? Like, this rough and tumble sort of place. But, okay, what were we doing? So, the idea of the experiment was that if neutrinos have a small mass—and in particular, that the different types of neutrinos have slightly different small mass differences—that when a neutrino gets created in a decay from a beam from the accelerator, the neutrino as it propagates, because of quantum mechanical effects, its so-called flavor can change. So, the neutrinos that get created in the decay pipes after the accelerator are called muon-type neutrinos. And if neutrino oscillations exist, which they do, the muon-type neutrino, after it's traveled a certain distance, should turn into an electron-type neutrino, and interact as if it was an electron neutrino, and then at some other point, turn back into a muon neutrino, and it would oscillate. It's kind of like rotating polarizations of light. There's an admixture, so the net polarization sort of sweeps around. It's not exactly the same, but it's this oscillatory phenomenon. So, the idea was you take two neutrino detectors-- now, neutrinos are very hard to detect because they have a very, very small interaction with matter. So, you have a thousand tons of steel instrumented, and they place two similar detectors at two different distances from the neutrino source. The idea was the measure the number of interactions of neutrinos that would create muons in one place, and then another place. If they differ, that would mean the mixture of muon neutrinos, or electron neutrinos, or other types of neutrinos, was different in the two places. So, in principle, it's a very simple experiment. You're looking for disappearance, essentially, of a certain fraction of the muon neutrinos. Okay, so, that said, in reality, you really have to understand the geometry of the neutrino beam, and the characteristics of the beam, and the shape of the detector, and how the beam would intersect with the detector, to understand whether any differences you measured from position one to position two were due to just side effects, parallax, different acceptances, angels, offsets. So, there are lots of things with orientation, and geometry, and surveying, and measuring, and all of that. So, while the measurement on the face of it was a very, very simple measurement—you're just looking for a ratio—there were lots of corrections that had to be worked out. So, most of the work was around doing some of the systematic studies that we had to do to convince ourselves that if we saw an effect, it wasn't due to some extra side effects. So, one of the things we needed to do so was to get a better idea of the shape and makeup of the beam itself that was going to create these neutrinos. So, I worked with a post-doc, Petros Rapidis, and we basically installed and commissioned and analyzed data from a special set of detectors that we put into certain places along the beam, way upstream between the accelerator and the experiments, to get extra information about the characteristics of the beam. These were in places where the radiation levels were extremely high when the machine was operating. So, obviously, the whole machine had to be turned off, and there were surveys and stuff. You had to go in, and walk into this sort of labyrinth structure to get in where these things had to be installed, and then they couldn't just be taken away, because they were activated. So, there was a lot of stuff around, obviously, radiation protection. And there were all these protocols where you had multiple keys, so you couldn't accidentally allow the machine to be turned back on. So, you had to learn that whole rigmarole around safety, process, and procedure. And then somebody built these detectors, and we put them in, and we studied them and used them as a way to help control systematics. In fact, once the data was analyzed, and we looked at these ratios, the very first pass looked like the numbers were different, that you were getting different numbers in these two detectors. But once we applied all the correction factors that were worked out through these various measurements, the numbers just came right back down to where they needed to be. Well, they didn't need to be, but where they needed to be if there wasn't going to be neutrino oscillations. So, we got, essentially, within experimental errors, we got equivalent measurements at the two locations. That enabled us, within the statistics of the experiment, to understand that if neutrino oscillations did occur, either you needed to go to a more sensitive experiment than the one we could do, or the mass differences were different than we were able to probe because of our geometry and our distances. And in the end, when they were discovered, with Sudbury Neutrino Observatory, and with Super-Kamiokande, that in fact, those neutrino mass differences were much smaller than anything we could have seen at Fermilab at the time. But I mean, we learned a lot about-- so, it was very satisfying in the sense that it all kind of hung together, and we got to learn a lot of the systematics of how these experiments are done. And it was a small group. It was like 25 people. So, we got to write code, we go to run simulations, analyze data, build stuff, test stuff, take data, and all kinds of things like that. It was really satisfying, and it was perfect.
Carl, when did you know you'd have enough to defend?
You know, basically, once we finished the measurement, and it was published in the Physical Review Letters, that was pretty much it. There was some fraction of a year-- but I mean, Mike just was like, “Write up a thesis and graduate.” It was quick.
Yeah. The findings were central, and the thesis was the afterthought, almost.
Right. It was like, “Get out of here. Don't stay.” He really encouraged me not to say. I know people that were graduate students for six or seven years, or even longer. I have a-- I'm not going to say, a certain person I know has been a graduate student, not in physics, for twenty years, or longer now. But there's this story, right, of the graduate student who never leaves.
Yeah, but obviously, Carl, you're a beneficiary of being a part of this successful collaboration where you really had something that could allow you to move on.
Absolutely. I mean, it wasn't because of me that the experiment was a success. Obviously, I was just a little graduate student, and they had this really strong group, and they did it quickly. And you know, Mike was just really supportive of-- he was just-- I mean, there are all these horror stories about people that don't get along with their thesis advisor, and their thesis advisor makes their life miserable, and all this stuff. It was completely the opposite of that. In fact, we're still good friends.
And besides him being just encouraging of you rapidly advancing, were you in close contact with him? I mean, was he mostly hands off as a mentor, even if you substantively had issues?
No, no, no, I talked to him all the time. I remember late in my years there, he was invited to give a big review talk at the international conference which was at Cornell that year. And I got to work with him on preparing that talk, and doing plots, and collating things. And he also encouraged me to look around, so I got very interested in double beta decay, which is something I never pursued, but I basically put a whole book together on how you might want to do a double beta decay with-- which isotope was it? It was Xenon-137, I think it was. And then the other thing, I can't even believe this when I think back on it. Towards the end of that experiment, of those years, around the mid ‘80s, he was getting interested in doing e+ e- physics, and eventually, he went on to join and be a leading member of SLD, which was the linear collider experiment at SLAC that ran in the-- must have been the late ‘80s and early ‘90s sort of timescale. So, SLD was just starting to come together when I was going to graduate. He invited me to go out to Stanford while I was still a graduate student for three or four months, and work on a test beam of some components of SLD. SLD was just a proposal at that point. But they were testing calorimeters for potential hadron calorimetry. So, he said, “Why don't you go out to Stanford, and you'll meet a whole new group of people. Maybe this is an experiment you'll want to work on as a post-doc, or something like that.” So, he flew me out to Stanford, and I spent-- I can't remember how long it was-- several months there working in one of their test beams with Vera Kistiakowsky, and-- Marty Breidenbach was the luminary, the leading light of SLD. He was an amazing-- I'm sure you know Marty Breidenbach. An amazing person. You know, definitely, to be around Marty was really inspirational as well. Yeah, so working at SLAC, the funny story is there was a movie that was popular around that time. I think it was called Like Water for Chocolate. No, no, it wasn't that. I can't remember. Anyway, it was a movie about Italian guest workers in Switzerland. It was this real kind of satire. It might have been-- I can't remember the name. Anyway, Italian guest workers in Switzerland. And there was this whole thing about how the Swiss made these poor guys live in chicken coops, and they would see the world between the little slats of the chicken coops, and the Swiss would be relaxing at the pool having drinks, and these poor guys would be living in chicken coops. And they said, “Okay, you're going to go out to Stanford.” And it was late winter. New York was really cold, and I had to leave my apartment on the Upper Westside, and it was like 5 in the morning or something, and I had to walk to the subway to take the subway to JFK to get a plane to fly to California. I had been to California, but in different context. So, I just remember there were people sleeping in the street, and it was New York in 1983. It was just dirty and really run down and gritty. And I got on this plane and flew to California, and this other graduate student picked me up at Oakland Airport, and we drove to SLAC, and we immediately got to Tresidder Union, which is kind of the campus center, and it was beautiful blue sunshine. Everyone was blonde. There was a jazz band playing. There was food, and people were on lounge chairs, and in bathing suits. I remember thinking to myself this is just like that movie where I'm coming from New York into this idyllic California--
Maybe, if only, you could make a career for yourself in California somehow.
Yeah, yeah. So, he sent me to SLAC, and that was pretty rich, because I got to work at an electron machine with a whole different group of people. Again, it was a very compressed time, but I learned a whole lot more about how to do other kinds of stuff.
Who were some of the senior people that you were able to interact with at SLAC?
So, there was Vera Kistiakowsky. She was a professor at MIT. I don't know if you've come across her.
Yeah. Her dad was George Kistiakowsky, who was a very important figure in chemistry and the Manhattan Project. Who else? I mean, I met Vera Lüth. I probably met her then. She was somebody who was pretty helpful to me when I was a post-doc, just connecting me up with people. That's a whole other story, but I probably met Vera, met Marty—there were a whole bunch of these people that were doing Cherenkov ring-imaging, which was like the hot new detector technology at that time. So, I met a bunch of those people. There were some other graduate students. I probably met David Leith at that time. Yeah, that's who comes to mind. And, of course, Hermann Winick was there at SSRL, and he was already an old family friend.
And was the post-doc new physics for you specifically? Did you see this intellectually as a continuation from your graduate thesis?
Well, this was not a post-doc. I was not a post-doc at SLAC. They just sent me out to SLAC as a graduate student just do a limited amount of stuff, just to kind of round out my experience on something other than neutrinos. Essentially, it wasn't in my thesis. It was just, Mike was like, “This would be a good experience for you.” So, he just sent me out there. I think part of the thinking at that time is it might have led to a post-doc at SLD. But no, that wasn't the post-doc, and in fact, I didn't end up being a post-doc at SLD.
Who was on your thesis committee back at Columbia?
Oh, I can't remember. I think Norman Christ was on my thesis committee. I think there was somebody from nuclear engineering. I can't remember what that person's name was. Maybe Wesley (Smith). I don't know if Wesley was still there. I'm sorry. That's a really long time ago.
After you defended, what options did you have available to you?
Right. So, at that point, the W and the Z had been discovered at CERN, for sure. And the new frontier, the new p[bar]p frontier was going to be Fermilab. They were building the Tevatron collider, and that was going to be, more than anything, the place where if new physics was going to be discovered, it was most likely going to be discovered there. SLAC and SLD was really interesting because it was the first linear collider, and they were going to do Z physics, and study Z to bb[bar], and things like that, but in terms of really going into the unknown, it seemed more like the p[bar]p collider at Fermilab was going to be the place to go. So, again, I don't remember exactly what happened, but I applied for a bunch of jobs, and there were some possibilities-- I think I got offered a position at SLAC. I can't remember exactly anymore. Chicago, I had a job offer to go to CERN and work OPAL at LEP, which was another thing that was going to do e+ e- physics. There was a Rochester job to go to Japan, I think, and work on TRISTAN, which was a Japanese collider. That unfortunately ended up having an energy that was just in between two interesting places. But, you know, again, it's a long time ago, but I think the thing I really wanted to do was to work on the p[bar]p collider. In fact, I remember when I wrote my-- at the end of your PhD, you have to write a little review article about some other physics topic, and I remember writing about W, production of Ws and whether there could be heavy Ws, or something like that, at the p[bar]p collider. So, I think I interviewed for some jobs-- yeah, definitely a few jobs, where I'd work on the Fermilab collider. I remember interviewing at Fermilab. I remember, obviously, then, interviewing at Berkeley, which is where I actually got hired. So, I did have a bunch of job offers, and they were all going to be different place. I remember somebody saying, “You really want to go to Fermilab. That's what you're talking about all the time. You want to work on the Fermilab collider.” And I was like, “I guess you're right.”
What was exciting about the Fermilab collider? What was the promise for new physics happening there?
So, the thing is, it was going to go to a new energy level. It was going to go beyond what had been done at the CERN p[bar]p collider. So, the CERN p[bar]p collider, it found the W, it found the Z, and it had very clear measurement of jet production. So, jets really kind of show that in hadron collisions, while you have this large, complicated object—the proton—that there are hard scattering centers—quarks, partons—and that when they interact strongly, you get these columnated jets of particles that come out. So, that had been the holy grail throughout the ‘70s, that there should be jets. But at fixed target experiments, they didn't quite have the center of mass energy to really see them as individual structures. They were too mixed in with the rest of the event. But by the time they had the 540 GeV center of mass collisions, or 640, whatever it was, at the p[bar]p collider, they were seeing jets. And they were seeing Ws, and they were seeing Zs. But what was missing at that point was if you go to higher and higher energies, does the jet behavior start to get modified by, let's say, sub-structure within quarks? So, looking at the very highest energies can give you new insight into structures that are smaller than the ones you currently know. Were you going to be able to find the top quark? Because that was still missing. We knew there was a b (quark). If you think there are three generations, there had to be a partner for the b, which was the top, and that had not been seen. Everyone's looking for it. They were looking for it at the CERN collider. At some point, they thought they found it, but it was completely wrong. So, the top quark was definitely a big trophy, if you like. There were all these nascent ideas that are still very, very important, like supersymmetry, sub-structure, technicolor, which higher and higher energy colliders could in principle shed light on. So, Fermilab was going to be the place where if any of these effects could possibly be seen, that's where you'd start to see them. And, of course, there was the Higgs. Nobody knew what the mass of the Higgs was. We really needed to nail down the other masses very well in order to constrain the mass of the Higgs to the point where we pretty much knew what it was going to be when it was finally found at CERN. And, of course, there was going to be the-- sorry, something just slipped my mind. The top quark, the Higgs --
No, no, I was going to say something else. Oh, yeah. The other thing is that there were feelings that even though Hadron collider physics was kind of messy, eventually, with refined techniques, we were then able to do a really good job on the W mass, and on potentially even starting to do spectroscopy. Like, studying the B particles, producing them at a hadron collider. See, the B-- the upsilon was discovered at the Fermilab fixed target facility by Leon Lederman. But once they knew the upsilon was there, if you want to study spectroscopy, if you want to study the energy levels and the hierarchy, you go to build an e+ e- machine. So, they built the Cornell storage ring, which was an upsilon factory, and then they could go up to the higher energy, and get the excited states, and they could do B physics. And then they could also make Bs at CERN, from the decays of Zs. So, everybody thought electron machines, those are the place where you're going to be able to do precision B physics, and the hadron machines are kind of like discovery factories. You find stuff, but you can't do the precision measurements-- but there was a feeling that with better techniques and new kinds of detectors, the Fermilab Collider could also become, and it did, a place where you could even do precision physics in areas that formally thought were unlikely, or were difficult. So, like I said, to use that metaphor again, there was a kind of frontier sense that you really were like, this is the highest energy machine, this was the most powerful detector. Everybody wanted to be there. That's kind of where you wanted to go. It was the place to be, I would say, around about 1985 and onwards, well into the ‘90s.
Carl, around this time, talking about higher and higher energies, when did you first become aware of the earliest discussions for the SSC?
So, when I was a graduate student, there was a project called ISABELLE, and it was an intersecting collider that was going to be built at Brookhaven. It was going to be a proton-proton collider, so it was going to have very high luminosity. See, the Fermilab collider collided protons with antiprotons. To make antiprotons is difficult, so you can't get as high intensity a beam if you're going to collide antiprotons with protons, at least in those days. So, if you want a really high intensity machine, you want to collide protons with protons. That's how the ISR worked at CERN back in the ‘70s. It was the unprecedented high luminosity machine, because they took two beams of protons, but because protons both have the same charge, they had to actually build two rings with two sets of magnets that would intersect. So, they wanted to basically repeat that at higher energy at Brookhaven. They were going to build a machine that was basically going to be a W factory, but it ran into a lot of technical issues around the performance and construction of superconducting magnets, and it threatened, really, the existence of the whole high energy physics field in some way in the U.S. So, everybody was really, really worried about this Brookhaven project. And at that point, the field could sort of police itself in some way, and they put together these very high-level committees to study and make recommendations. So, essentially, there was a committee that was formed to look at Brookhaven, and the committee said, “We think that they can solve their problems, and the project should be continued.” But then things didn't improve, so they made a second committee. That committee met at Nevis, the lab where I was writing up my thesis. So, I remember all these trucks from Washington came in with a whole administrative team and all these distinguished people that came in and had these cloistered meetings. There were reporters, typically from like Long Island. They were like climbing over the fence wanting to know what was going on. So, we were just like playing volleyball, and I was very aware of what was going on at Brookhaven. And this committee decided -- I think Stan Wojcicki was the head of the committee. This committee made the recommendation that the Brookhaven project should be terminated, and that instead, the US should refocus itself around a new project to build a much higher energy machine, and that would be called the Superconducting Supercollider. So, they were trying to deal with lemons and make lemonade, or something like that. And it was audacious, but that's what they did. And then, Reagan -- it's a long story. You can read Mike Riordan’s book -- you probably have. But eventually, they sold the project to Reagan and he's like, “Aim high. Go for it,” and the Supercollider became a project, but it was now a very large project, and they couldn't self-police anymore. About ten years later that one got killed also. It's amazing that the field still exists, if you think about it, how many problems there've been. But particularly because the committee was meeting at Columbia, I was very aware of the Supercollider.
What did you do next? What was the next big thing that you worked on?
So, I got some job offers that would allow me to work as a post-doc on particle physics at the Tevatron collider. So, the job that I took was with Lawrence Berkeley National Lab, where I still am employed. They hired me as a post-doc, and my supervisor was Bill Carithers, who had been at Columbia. Not in my day, but earlier. I think he'd been an assistant professor. He worked with Jack Steinberger on kaon experiments. Willi Chinowsky, who was a professor at Berkeley, but had been a Columbia undergraduate and graduate student and had worked with Jack Steinberger back in the ‘40s and ‘50s. Bob Ely, who was another Berkeley professor, and then the kind of young star in the group was Jim Siegrist, who is now head of the Office of Science, Office of High Energy Physics, at DOE. He eventually became a Berkeley professor. And then, the post-doc just above me was Melissa Franklin, who is now, for many years, has been a professor at Harvard, and works on ATLAS. And then there were a bunch of graduate students, and then off I went to Fermilab, immediately, to work on testing and setting up components that would be part of the Collider Detector at Fermilab that had not yet been put together.
So, as a Berkeley post-doc, you're immediately back to Fermilab.
Back to Fermilab, living on site at Fermilab. For the entire first year of my post-doc, I stayed at Fermilab living on site. Berkeley had a house. We rented a house. People would come and go. Melissa was there most of the time. Jim would come and go. Willi would come and go. Melissa, I think-- who knows anymore? But I was there for a year. And we were in a test beam, once again, testing components that were going to become part of this collider detector that was just being put together. So, that was 1985. We were working really closely with the group from Harvard. That was Roy Schwitters group at the time. And also, the group from Japan from the KEK laboratory, and we were all together in this underground test beam, testing components of the calorimetry. These are the energy measuring detectors that were going to become part of it. But I was now in the CDF group, which was a much bigger family, so to speak, than I had come from. It was hundreds of people rather than tens of people. But still, it was a very close knit, and very collegial environment. There was a large presence of Italians there, who I became very, very friendly with, and ended up being extremely close colleagues with. I would say, the leading light, as far as I was concerned, was Alvin Tollestrup, who sadly passed away, I guess, last year. He's a remarkable-- I don't know if you ever did an oral history with him.
I didn't get a chance to, unfortunately.
Yeah, he was the real deal. I mean, this guy was a real physicist. Unbelievable. Just an amazing person, in so many ways. So, even though this was a huge experiment he made it a community, really.
Was this a largely experimental world you were in, or were theorists part of the mix as well?
Well, there were a lot of theorists around that would come to our meetings, and we'd talk to them, or sit with them at lunch. They were, of course, all very excited about stuff that would go on. So, there were people like Michelangelo Mangano, and Keith Ellis, and BJ Bjorken, other people. There were definitely a lot of theorists. I don't think we spent a lot of time at the blackboard with them, but yes, there was definitely a community. Fermilab had a theory community that they fostered. That was one of the great successes of Fermilab, was the theory community, with Chris Quigg putting a lot of that together.
What were some of the key technical challenges as you were working through this work?
So, calorimeters are energy measuring devices. So, a beam goes in, and there's some substance that responds to the beam, and a signal comes out. So, of course, you need to know the relationship between the signal and the beam coming in. That's called calibration. So, essentially, you spend a lot of time calibrating a calorimeter by putting known beams into it, and its calibration varies with angle, with position, with composition. So, there was a lot of systematic work. People were always trying to figure out ways to build calorimeters that were more uniform, that were easier to build, that were more stable, and so forth. People have built calorimeters filled with scintillators. People have built calorimeters filled with liquified noble gases. People have built calorimeters filled with gas. They all have their benefits and their detriments. So, for better or for worse, the calorimeter that we were working on was called the gas calorimeter. It was filled with gas, and the signal that we'd measure was the amount of ionization which was proportional to the number of particles that were created when the high energy particle hit the calorimeter. It would create a shower as everything broke off, and by basically measuring all the shower sub-products, you've got a measurement of the energy. But there were a lot of effects that maybe were not seen clearly from the onset that affected the calibration that we ended up spending a lot of time trying to understand, calibrate, and so forth. One of the extreme effects in this calorimeter was because it wasn't pressurized. So, essentially, we flowed gas through it, and the gas came out and bubbled out through a bubbler. So, the pressure of the gas would follow the atmospheric pressure in Illinois at the time. So, whenever a storm would come through, the pressure inside the calorimeter would change, and the signal coming out would change. These gas calorimeters respond more dramatically to the weather than they do to particles. So, I was like, we've built a weather station here. Not a particle detector. So, yeah, that was interesting, right? People are always arguing in experimental physics about technique. Like, I'm going to build a calorimeter this way, I'm going to build it that way. They always start off with some really pure assumption that this concept is beautiful, and it will result in a great device, but then there's all the weather, and the air pressure, and that kind of theme repeats itself over and over again, I think, in the history of technology. There's the vision, the dream, and then there's the reality of making it actually work. Sometimes you can do it, and sometimes you're really successful. But that's a lot of what you learn in any field. Astronomy, wherever there's an instrument, that's what you learn when you're trying to get an instrument to work. So, the calorimeter had a lot of issues around it. But we learned a lot, and then I just did a lot of other things. Setting up the high voltage system, working on a software to monitor the voltages in case anything trips. You know, there's just a lot of work to support to operations of this calorimeter. Definitely, I learned a lot, and it was interesting, but it wasn't exactly my thing. I definitely felt like I was helping, but it belonged to other people. It wasn't ever going to be-- I didn't really feel like I was going to put my own imprint on it, which is fine. I didn't have to do that. But late that year, late in 1985, an opportunity came along which at the time was extremely risky, but it was something that looked to me to be so interesting that I thought, well, this is something that I could do from the ground up, and maybe it would be a good thing. And that's what I did. I was given really good support by Carithers and Chinowsky, and all those guys. They were really supportive of it, but probably we're talking today because I had that opportunity. I was still a post-doc, but eventually I got promoted, and I got to stay at Berkeley, and it's probably because of the work I got to do after I stopped working on calorimeters.
I'm in such suspense. What is the work?
So, what happened was in October of 1985, there was the IEEE Nuclear Science Symposium, and that is a yearly meeting. It happens in Europe, Asia, and the US. It moves around. It's the big detector meeting, electronics, for nuclear science and detectors that happens. So, that was happening in Berkeley. We got to fly to Berkeley to go to the Nuclear Science Symposium, and I think we might have even made some talks about calorimeters. But the Italians on CDF from Pisa—in particular, there was a guy called Aldo Menzione—they had proposed an idea back in the very beginning of CDF. It was sort of included in the proposal as something as something that maybe could be done, but not at first, which was to put a new detector right on top of where the beam collisions occur, right deep at the center of CDF, that would be made of silicon, and built using solid state electronics techniques, that would be much more precise in tracking the trajectories of the particles than anything that anyone else was building at that time for an experiment like CDF. So, that technique has various names, but it's sort of called the silicon vertex detector. The idea is beams collide, and a reaction occurs, and stuff comes out. So, a detector that tracks basically measures points along the trajectory, and you can trace the curvature of the tracks on the magnetic field to measure their momentum. But if a particle is created, and then after a very short distance, like less than a millimeter, it decays into other particles. If you can track those daughters back to a point which is different than where all the other particles are coming from, that's called a secondary vertex. That shows you that something happened that was a very short-lived particle that then decayed. But you don't see it. You just see its products. So, this idea of a precision vertex detector, it wasn't in and of itself a new idea. At Stanford, they were building something like that for the electron e+ e- collider. And in the ‘70s, people had tried to do things like that in fixed target experiments with sort of limited success. But the Italians wanted to do it at CDF in a hadron collider, which was an extremely complicated environment with large numbers of particles. Lots of backgrounds and radiation issues, and an extremely small amount of access. So, it was technically really difficult. I would say almost everybody except Aldo, and maybe a couple of other people, just thought, okay, yeah, just include it in the proposal. It'll never happen. It's just impossible. There's no way. There's too many wires, there's too much heat, there's too much this, too much that. It's a dream. But this man was a visionary, and he was one of these guys that's like, if it was a pretty idea, it meant that there had to be a way to make it work. He just had this incredible faith in all these things. So, he came along, and he was like, “We are going to make a vertex detector for CDF.” And everyone was like, “Yeah, sure Aldo. Whatever you say.” So, off we went to this IEEE meeting, and there was a meeting held the next day, or the day after, or something, in the main conference room at Berkeley, to talk about what Aldo was interested in with all sorts of colleagues who were visiting from Europe who were working on different types of vertex detectors for LEP, and other things. And they all talked about what they were doing, and their different ideas. It's a long story, but there were just practical issues that would make what they were doing not really scalable to what we needed to do at the Fermilab collider. So, this guy shows up, who nobody had ever seen before, who said, “I work here.” And we were like, “Oh, you work here? Never seen you before.” And he goes, “Yeah, I got an undergraduate degree in psychology, but I'm really interested in electronics, so I kind of taught myself how to design integrated circuits, and I think I have a solution for what you guys need to do. If you just do this, that, and the other thing,” and it was sort of like, what is this? It turned out, there was this guy, and his name is Stuart Kleinfelder. You should do an oral history with him. He is a complete genius, no question about it. The real deal. He had this vision of kind of an electronic scheme, using a new integrated circuit that he would design, that would make this idea that Aldo had practical. I have to say, honestly, the powers that be in the world of engineering around Berkeley were like, “Who is this guy, coming in? He's not serious, he doesn't have credentials. He's promising the world. It'll never work.” He encountered a huge amount of resistance, but what he was proposing had such beauty to it that it just looked really enticing. I just said to myself, this is what I want to do. It was really, like, I didn't have a family at that time, and not a lot to risk, you know what I mean? But I was like, this is what I want to do. Carithers and Chinowsky were like, “Okay, it's your career.” But there was an undercurrent at Berkeley that these silicon technologies were going to be really important for the future. There were people like David Nygren and Helmuth Spieler who were incredible. Really brilliant—David’s a genius—brilliant people, who had worked in other areas. And they were like, “Silicon is where we need to put our money.” And they were organizing a silicon effort aimed at the SSC. So, it was kind of like a perfect storm. There was a giddy optimism about it. There was this kind of visionary Italian, there was this person that just kind of parachuted in, and all the ingredients were there, but I felt like there was room for a post-doc to sort of interface between all these different characters, and try to actually realize the thing as an option, you know, try to really put this together. So, I basically stopped working on the calorimetry. It was a gradual thing, but I kind of ramped up my involvement in the silicon, and within a couple years, we had written a proposal that was submitted to the Fermilab Program Advisory Committee with the Italians, and all that, which really now had a technical design for this thing, with costs, and parts, and simulations. It was an incredible document, and they approved it. So, this all kind of started in 1985. It was probably approved by like 1987, ‘88, ‘89, something like that. And we built it, and it became more and more people involved, but we built it, and it took its first data on May 12th of 1992, and it worked. Eventually, it was a key component in the discovery of the top quark, because the top quark decays into b quarks. B particles live for about 10^-12 seconds, so at roughly the speed of light, they go hundreds of microns before they decay. So, you can measure the offset due to B particles. So, you look for an event that has the right topology and energy distributions to be consistent with a particle like the top, but if it has these fingerprints of decays deep inside, it’s like the golden thing. It’s what you’re looking for. And so that technique of secondary vertex detection with silicon detectors in a hadron collider, nobody had ever done it in that environment before. That became a very successful thing, and then it started a whole sequence of improvements around making it bigger, making it faster, making it have additional characteristics and features. (Earlier I mentioned the possibility of doing B meson spectroscopy and B physics at the Fermilab collider, well withing a year or so Barry Wicklund and Fumi Yukegawa were able to exclusively reconstruct B mesons at CDF using the vertex detector. It was the beginning of hadron collider B physics.) And then, at the same time, people were planning experiments for the Supercollider. This was now the early ‘90s. And the Supercollider experiments were all going to have even bigger versions of this silicon detector. That was the right technology for the Supercollider. It had been proven that you could do it at Fermilab. So, all the Supercollider detectors had large silicon systems. When the Supercollider was canceled, the Berkeley group, which was now a silicon group, joined ATLAS, or could have joined CMS, the other group. They all have huge silicon-- so, it's like silicon is an industry now, and hundreds of people are working on it, but it was super interesting and fun to be able to be a part of when it was first shown that it could bite back in those very early years.
Carl, I'm curious if you had any interaction with Peter McIntyre during this time.
So, Peter McIntyre was—or is—I don't know what he's doing now, but he was a professor at Texas A&M University when we were in the test beam working on gas calorimetry. So, there were four calorimeters that were being tested. One built by the Japanese, one built by Berkeley, one built by Harvard, and one built by Texas. So, the Texas calorimeter was built by Peter McIntyre, or his group. I guess, there was a guy called Bob Webb who was a part of that, too. So, Peter would come in and out, but he wasn't somebody that I had a lot of direct interaction with. I definitely would see him; he'd come by the counting house, and stuff. He was a guy, I think, who had come out of the Carlo Rubbia juggernaut, and was sort of pushing big ideas. And I think because he was in Texas, and it was the Supercollider time, he was probably trying to stake out some activities around the Supercollider. But that was the extent of my interaction with him.
How long did you stay on this next project?
Well, I'm still working on it. I'm still working on silicon detectors. We built the very first one in the early ‘90s, and then it got upgraded. There was a second one in ‘94, and then it got upgraded some more in the late ‘90s. By then, we were also working on ATLAS, so we built-- not me alone. It became large numbers of people, and I was just part of it. I've almost never taken any kind of official leadership role. I've never been the director or the head-- I had a sort of leadership role in some project management stuff most recently, but mainly, I'm mostly kind of hands on, in the lab sort of person. So, they're always like, he's the person who-- that's the project leader. It wasn't me. But then we built a big, very large meter scale with hundreds of other people that is now part of ATLAS. In the late ‘90s, and early 2000s, we were planning a fifth generation of the Fermilab silicon detector, and we came up with some new ideas about how to build one that would be much bigger, and much lower in mass. You want everything to be super light, so the particles pass through without scattering. That final iteration of Fermilab was canceled because the powers that be decided, “Sir, it's moving to CERN now. This is over.” But we had introduced some, I think, really interesting ideas that we didn't get to realize in construction finally at Fermilab. But once we finished building the present version of the ATLAS detector—which is taking data and was used in the Higgs discovery—we took these final ideas from Fermilab, and we kind of permuted them, and reapplied them to a future version of a tracker at CERN, which is now a big project that we're all still involved in. We're building what's called the ITk Strips Tracker. It's much larger than anything else we've ever built. It's like-- what is it? The one that's in there now has around 4,000 subunits that are each like a camera, in a way. And this one's going to have like 20,000. So, it's much bigger. But we took some of the ideas that we had finally worked out towards the end of the Fermilab period, and we kind of changed them into a new way of building a really large tracking system, and that's what we're doing. So, it's a continual-- that's what our day-to-day work is now. It's building this very large tracking system, using ideas that have just been carried continuously, step by step, through back to these early experiments, 30 something years ago.
Carl, given the fact that you've stayed with the project for so long, have the overall goals remained singular? Has the project reinvented itself as physics has advanced more generally?
I would say, the fundamental concept of a particle detector for collider physics is that beams collide, and particles come out. The particles that come out are either protons, pions, or kaons, heavy hadronic particles that interact very strongly with matter; electrons, muons, things like that, that interact different than hadrons; photons, and neutrinos, and other stuff that we don't know about. To detect this broad range of possible particles that come out, there's a certain way that detectors are built. They use energy measuring and absorbing components, and they use precision tracking components, and they use very fast electronics to get quick information about what's going on so that you can decide if something interesting has happened. So, at a very high level, that basic scheme was present at CDF, it was basically present at the ISR in the early ‘70s, it's present in ATLAS today, and it will be present in ATLAS, so called, Phase-2 which is the planned high luminosity upgrade of the Large Hadron Collider, the HL-LHC. But the scale, the complexity, the number of channels, the level of technology, the precision, all of this just gets more and more powerful and complicated and expensive. I made a table once—which I do in lectures when I talk about this material—I showed that if you look at five or six generations of these detectors, it's the same basic idea. Precision tracking, looking for vertices, measuring curvature, and so forth, but every one of these detectors that got built -- early ‘90s, mid ‘90s, early 2000s, 2020s -- the underlying equations are sort of the same, and every single one of them used the best technology that was available at the time, right at the state of the art. You couldn't do any better at that day. Yet, the conditions under which these detectors operate have gotten more crazy and more complicated by a factor of a million. So, it's a testimony to technology, particularly electronics technology, that we've been able to do this. We're riding a wave that comes from cell phones, and fast computers, and data storage. All this amazing technology that fuels a lot of commercial stuff. We've basically been skimming the cream off that to build these more and more powerful and complicated and large, but important scientific instruments. So, it's been a perfect storm. It's been a great intersection of the world of technology with the needs of fundamental science. But basically, it's the same thing.
How did the cancellation of the SSC change the overall collaboration, if at all?
So, the SSC was-- there were going to be two large experiments at the SSC. One was called SDC, the Solenoidal Detector Collaboration, which was led by George Trilling. And another was going to be called GEM, and I think it was led by Barry Barish. And when the SSC was canceled, all the people that were on SDC and GEM sort of regrouped themselves. Some of them joined ATLAS, and some of the joined CMS, which was the other-- so, there were these American beachheads. All the people that were working at Fermilab that wanted to work on SSC, they all joined CMS. So, there's this huge Fermilab/CMS component.
So, it's all eyes on CERN at this point. Things don't get bigger at Fermilab as a result of SSC getting canceled.
Well, all eyes on CERN as far as collider detectors go. As you probably know, there's a huge effort at Fermilab to build a deep underground neutrino experiment, and shoot neutrinos to South Dakota, and all sorts of other neutrino physics, in a very, very prominent way. And if there was ever going to be a linear collider, obviously there's an interest at Fermilab in superconducting RF, and all that sort of stuff. So, Fermilab reinvented itself primarily as a neutrino lab. It ran the collider for many years, into the 2000s, but eventually the collider stuff kind of trailed off. In particle physics, we talk about frontiers, and so there are these three -- it's a marketing thing. I'm sorry, but there are these three frontiers: the energy frontier, the intensity frontier, and the cosmological frontier. In the books they give Congress, and stuff, they show this pie chart of the three frontiers, and all that. So, the energy frontier is what physics we can do at really high energy. The energy frontier was at Fermilab when we were at CDF. Then, the energy frontier moved to CERN with the Large Hadron Collider. If they build a larger collider, or they put new magnets in the CERN tunnel, or if they build, it will stay at CERN. If at some point in the mid-decade, they build a huge collider in China, the energy frontier will move to China. The energy frontier goes to the highest energies and looks for the physics that could only be reached at these very high energies. The cosmic frontier says, “Okay, no, no. The way to do fundamental physics is to look for effects essentially from the Big Bang that have persisted in some way that we can measure on the spot.” So, cosmic microwave background radiation fluctuations, dark energy, dark matter. Dark matter, a little more complicated. So, you know, the poster child is the accelerating universe that came from studying supernova. Lot of high energy physicists migrated into that area, and DOE supports and NSF supports telescopes now, and groups of people that are doing cosmological physics-- LSST, the Large Synoptic Survey Telescope is part of the cosmic frontier. It's taking large data sets-- you know, it's a high energy physics mentality. Like, huge amounts of data, large-scale projects, data analysis, and you can address questions of fundamental physics. The intensity frontier says there is deep end fundamental physics that we can get at by looking in special corners with really sensitive experiments. For example, the muon g-2 that was just announced a couple days ago, that's a prime example of an intensity frontier. You do a super precise experiment, looking at lots and lots and lots of muons under very special conditions to look for a small deviation from its magnetic behavior which could be indicative of quantum corrections to the muon's nature. That gives you insight into fundamental physics. So, it's kind of like a complimentary thing to the energy frontier. Instead of going out to high energy, you go out to super sensitive measurements. The neutrino beams that they want to shoot to South Dakota, that's intensity frontier. You go to a very, very intense neutrino beam, and you attempt to measure a very, very small effect which can give you insight into CP violation in the leptons. In fact, DOE's program offices, right? There's like the Intensity Frontier Office, the Energy Frontier Office, and the Cosmic Frontier Office, and they're different people working in those offices. So, Fermilab has-- I went through this long diatribe to say that Fermilab has kind of made itself the premier intensity frontier. They went from the premier high energy frontier to the premier intensity frontier lab. That's kind of their strategy.
Carl, when did you have the sense, from your vantage point, that finding the Higgs was going to actually happen?
So, as I said, I'm really a kind of hardware person. So, once we had built the stuff we were going to build, the natural progression for 95% of people would be to now stop building stuff and get involved in data analysis. And the most interesting, or the highest visibility thing you could have done at the Large Hadron Collider was to join one of the Higgs analysis group. So, people I knew were working on Higgs, and I was aware of what was going on, and that it was coming together, and so forth. But I was not attending every meeting. I wasn't part of that. By that time, I was deep into taking these ideas from Fermilab and trying to figure out how to build new, or bigger, better version of an even larger collider detector based on silicon. So, yeah, I'm an author on these papers, with thousands of other people, but I didn't make any contribution to the analysis of the data, or the interpretation of the data that led to the discovery of the Higgs. I was aware of it at about the same time that anybody on ATLAS who was not working directly on it would-- I mean, there are people that I'm very close to that worked directly on it, but not me.
As a hardware guy, what were your feelings when the Higgs discovery was actually announced?
Yeah, that's an interesting question. What they did is at Berkeley Lab, when the Higgs particle was discovered, they asked us to be on a little panel, and they invited people into the auditorium to talk about the discovery. So, there was the hardware guy, there was a theorist. The head of our group at that time was Ian Hinchliffe, who was a theorist turned experimentalist. Brilliant guy. You should interview him. He was on the panel, and somebody else. I can't remember, a bunch of us. They were asking us; “How did you feel about this? What is your impression or your reaction to it?” And the thing that I said is essentially this was an incredible experimental achievement if you look at all the work that went in, and the years of searching for the Higgs and not finding it, at other energies, and all the techniques that had to be brought together. So, of course, the experimental community deserves a lot of credit and satisfaction. But if you actually look at the Higgs mechanism and how it works theoretically, it is such a complicated and unexpected conspiracy of subtle effects between the structure of the Standard Model, broken symmetries, the Higgs potential, Goldstone boson. Put the whole thing together and it's almost like a Rube Goldberg thing. And it's like, that was actually right. That they actually-- this particle that was predicted to exist in this complicated scheme that accounted for all this weird, messy stuff, like some of these particles are massless, some of them have a big mass, and symmetry broken. If you just sort of were introduced to it, you're like, wow, that kind of looks pretty cobbled together. But it's amazing. It's not like Maxwell's equations. It's not this simple, beautiful structure. It's complicated, but it was right. I just found that really incredible that the theorists were able to do this. So, that was my reaction.
When did you get into the audio stuff?
Okay, so that's a whole other story. So, the thing is, when you look at particle detectors-- the earliest particle detectors that anybody used back in the late 19th, early 20th century, some of them worked on electronic processes in a gas. So, you had a gas filled chamber, and a particle went through. It creates ionization in the gas. They put a large electric field in there which caused the charge to separate and create a current. So, that was Geiger’s idea, a Geiger counter. Conceptually, it's a lot like the detectors we build today. Instead of gas, they might be made of silicon, or liquids, or gases, but Geiger kind of nailed the basic idea. The other thing they realized is that using other properties of matter, you could image the effects of particles to turn them into things that were visibly recognizable, a micro-phenomenon that were visibly recognizable, rather than an electrical signal. So, the two techniques were the cloud chamber, which was invented by C.T.R. Wilson in the early 20th century and the photographic emulsion. The idea of the cloud chamber was that you have—it's almost like the Higgs—it's such an amazing thing that they figured it out. You have a vessel with a vapor that's super cooled. So, the vapor is really ready to condense. And a particle goes through, and the condensation is nucleated on the trail of ionization. Have you ever seen one of these things, like in a science museum?
A lot of science museums have them. You could find one on YouTube. You'll see these wispy trails appear, and then drop out. So, Wilson was studying clouds, and he wanted to make clouds in the lab, because he was interested in optical phenomenon related to meteorology. So, he built a cloud chamber in his lab, and he noticed that occasionally there'd be these trails that occurred in them. Then, he brought in a radioactive source nearby, and he suddenly saw lots of them. So, he realized they were cosmic rays that were causing condensation. It turns out that this effect he observes in his little test chamber, cosmic ray induced ionization, actually has a huge effect on the world—essentially, there's a global electric current that flows through the atmosphere. We have all these lightning strikes every day that bring charge to the Earth, and then cosmic rays cause ionization effects in the atmosphere that brings the charge back up to the sky. So, there's all this weird stuff that Wilson ends up discovering. On the way, he discovers that you can visually see condensation trails from particles. So, this becomes a tool in the lab for doing particle physics. Rutherford, Blackett, all these people do fundamental discoveries into the ‘20s, and ‘30s, and ‘40s using the cloud chamber. Fundamentally, you take a picture with a camera, and you look at the picture, and you get data from it. The other thing was Marietta Blau pioneered in the ‘30s and ‘40s the use of photographic emulsions. So, just like light can make an emulsion exposed, ionizing radiation can as well. And if you arrange the emulsions in the right way, and then you look inside them after you develop them, you see tracks. In thick emulsions, you can see tracks from particles. So, the emulsions end up being put up on mountaintops all over Europe and South America. Important discoveries, the pion for example were discovered to with emulsion images and the muon and the positron with cloud chamber images. Then, in the ‘50s, Donald Glaser basically turns the cloud chamber upside down, and makes the bubble chamber, which also yields a huge scientific return, well into the 1980’s including neutral currents. Same idea, but you've got a super-heated liquid that boils along the tracks of particles. So, there's this current of imaging-based detectors that, if you actually did a scorecard, probably more fundamental physics across the 20th century was done with these-- all we did with these electronic detectors is discovered the Higgs, the top quark, and a few other particles. These imaging detectors, the scientific bounty is immense.
Yeah. Doesn't get quite the media play.
Well, the thing is, they're slow. You can't use them at the collider where we get collisions 40 million times a second. But there's this current of imaging detectors that play this role. But by the time I'm working as a post-doc, everything is electronic based. It's essentially Geiger's idea, but reinvented in silicon, in this case. You ionize matter, you collect electrical signals. So, I really loved this idea of an imaging detector, and I just was always wondering, could that be something that has a future. Is there some corner of physics that we could revisit with imaging detectors? So, it's just a thing that I would think about and wonder about. So, when we were building the ATLAS experiment in the late ‘90s and early 2000s, what we were doing was -- I told you -- the ATLAs detector was made of like 4,000 pieces of silicon that were created in a microelectronics foundry with all kinds of minuscule precision features on them, and so forth. Every one of them had to be measured and aligned in a certain way to be built. So, we had these colleagues from Manchester, in England, and they designed a system which had a microscope, and you'd put these silicon detectors into the system, and the microscope, under the control of a computer, would go around and there'd be a camera, and it would take pictures under magnification, of different features. And then they would be in the form of a digital image. Now, it wasn't a photograph anymore. It was a digital image. So, a digital image is just a list of numbers, almost just a table. So, I'm looking at you on the screen, you're made up of pixels, and each pixel has a certain color value to it. So, if I don't look at you, if I just took the data, I could manipulate it and do things to it. Average it, smooth it, do anything I want. So, these guys in Manchester -- this wasn't an original idea-many people do this -- they wrote programs to take the images of these corners, and edges, and special features, crosses and circles and stuff, and do math to them, in order to extract the distance from one edge to another, and the position with respect to something else. I had never encountered that technique before. It's basically called image processing. You take an image, you treat it as a mathematical object, you analyze it, and you reach some conclusions about it. But the thing is, when we would run this code, we would get reproducible data on the scale of like a micron. A micron is like a millionth of a meter, a thousandth of a millimeter. I was super impressed with how well that worked. I was like, this is really great. What else could you do with this? That's not original. I mean, it's the same stuff that you use for like facial recognition, software, and myriads of industrial applications, and cancer analysis of radiography. They use image analysis all over the place. It's an entire field, right? But I encountered it, and it was like, “Wow.” So, I'm like, “Okay, images, and image analysis, physics applications, what could that be?” So, one day, I was driving between Silicon Valley and Berkeley, which is a thing I was doing a lot because we were working with these companies that were building ATLAS components for us, and I have to go down there and talk to them, and so forth. So, driving along, and I'm listening to the radio, which is like our public radio station in the Bay Area, KQED. They have this public affairs forum from the Commonwealth Club. It's like this thing where they have speakers come in and talk. So, the speaker is Mickey Hart. Do you know him?
He was one of the two percussionists for the Grateful Dead.
Okay, yes, yes. Okay. I should have figured, right.
Right. So, it turns out that Mickey Hart, in addition to being a musician, and a member of the Grateful Dead, and all of that, was kind of a passionate advocate for the world's recorded sound heritage. He worked on this and served on an advisory panel for the Library of Congress, and this was one of his causes. This was something that was very important to him. So, he gave this impassioned talk about sound recordings, and how they were delicate and damaged, and they were going to be lost forever, and languages that were going extinct, and all sorts of things. Actually, he wrote a really wonderful paper about this that was published in the Journal of the Audio Engineering Society. It was entitled. I think, “A Musician's Plea to the Audio Engineer.” Just listening to this thing, I just was like -- I thought, “Well, if you could image the phonograph record,” the same way we were talking about analyzing images that were particle tracks and things, “if we could image the track of the record groove, perhaps we could apply an analysis to it. Our imaging methods are so precise. How precise would you need to measure the groove to get the audio information out?” So, that was just kind of a eureka moment. I thought, that would be cool. The thing is, from my experience working with silicon detectors, one of the really big themes that you encounter when you're working with electronics and particle detectors, is the whole idea of signal and noise. I was enmeshed in signal and noise throughout all those years, going back to the 1980s. Helmuth Spieler, who was kind of our intellectual guru on how to build all these detectors, from an electronics and signal processing point of view, he showed us that noise was the thing. You had to understand noise. So, I knew that in a phonograph record, there was going to be a noise level. And below the noise level, it didn't matter how well you could measure because the noise was a background that you could never beat down once you got to the fundamental noise of the material. So, I knew that I did not need an arbitrarily precise measurement method. I just needed to do a little better than the noise. So, that immediately got me excited, because I was like, “Well, if the noise is at a micron, I'm home free.” So, I came back, and I remember going to Jim Siegrist and saying, “I've got this idea,” and him just breaking out laughing. That's like Jim. He always laughed. And I remember he wrote it down in his notebook. I don't know where that notebook is now, but he was like, “Yeah, sounds like a good idea.” But then, I went and started to look around online to see if this could actually work, and what are the numbers, and what are the noise levels? I was really lucky. I went into this used bookstore in Berkeley, and I found this bible of audio technology from the ‘40s, because we were talking about old sound recordings. Not the stereophonic recordings that you buy at Sam Goody, or whoever, that the Grateful Dead, or Bob Dylan, or The Beatles are recording on, or Leonard Bernstein. We're talking about old recordings that are not in good condition. So, I expected I might be in a pretty good place. So, the numbers looked kind of promising. I found this record store near Berkeley that sold old, used records. They had this bin in the side of the room with old 78s. Some of them were broken and scratched up. These were the records that your grandparents or great-grandparents-- I don't know how old you are, but from the ‘40s, ‘50s, ‘20s-- early period. So, I found some, brought them into the lab, and started looking at them under the microscope, and it kind of looked promising. So, this was around 2000, and I started kind of talking about the idea occasionally, and it almost was like a joke with the post-docs in the lab. We'd talk about this idea. Yeah, wouldn't that be funny. That would be a funny thing to do. But finally, after a couple years, I think it was in late 2002, this post-doc-- and at this point, I'm already-- I was probably a senior scientist by then. Maybe. Anyway, who remembers? But a post-doc in the group, who's a really brilliant guy, Vitaliy Fadeyev, who still works on ATLAS, he's now at Santa Cruz, he came in on a Saturday, and he wrote a little program on one of our measuring machines to basically photograph a sequence of images of the groove of this record that I had brought in from the shop. Then, with that data, there was an analysis that he applied that essentially turned these pictures, through this image processing technique that was available to us, into a waveform that you could then just drop into an audio player, like whatever the player on your PC -- wave player. I don't know, what is it called? Windows Media Player, or QuickTime. You could just drop it in there, and hit play, and it sounded like the record! So, that was, well, wow. I mean, that was really exciting. It really seemed like it worked. So, we did some studies, and we wrote up a paper about this. A regular scientific paper explaining what we had done and what we thought the potential was. And we just googled around, and we found a few people at archives and libraries, particularly the Library of Congress, who we thought, let's try this out on them and see if they think it's a good idea. So, I sent it off blind, and we get this call back from the Library of Congress, which says, “We'd like you to come to Washington.” So, there was a guy at the Library of Congress, Peter Alyea, whose father was a cosmic ray physicist at the University of Indiana, and this guy was an audio historian, audio archivist. He understood our language. Like, the way our paper was written totally resonated with him. So, it was one of those lucky things. Also, at the Library of Congress, Peter was deeply in this huge discussion, at the time, on how to automate the process of transferring thousands and thousands of old recordings into digital format. David Woodley Packard was the son of David Packard of Hewlett-Packard, he runs a philanthropy called the Packard Humanities Institute. He's a classics scholar, I think. Anyway, he had donated like $100 million to the Library of Congress to build a national audio/visual conservation center, which exists now in Culpeper, Virginia. They were getting ready, basically, to either build that place or move into that place. So, they were very primed for new technological solutions to the problem of transferring audio from physical media to digital formats. So, Peter, the way I heard it was there was a conversation between the head of preservation at the library and Peter, and they were like, “Does this make any sense?” And Peter says, “I think we should talk to these folks.” So, off we went. I think it was June, we went there, and they offered to give us a little bit of money to research this further. Then, Pier Oddone, who was the assistant director of LBL at the time, he's a particle physicist. He totally got what we were doing, and he gave us some money, and we were able to sort of jump start developing this idea into a practical solution that could be used in libraries and archives to utilize optical methods and image analysis with no physical contact to the media, not touching anything, and bring that media into a digital form. Earl Cornell, at LBNL also joined the project at this point as well, and he has played a tremendous role to this day. So, this idea, when it first started, it really kind of caught the eye of media. There were literally dozens of press inquiries and articles and all sorts of -- everything from like Physics Today, to some newspaper in Kansas, to Canadian radio, and German radio. I mean, we were constantly giving interviews and inquiries, and stuff. And everybody loved the story that it was a bunch of physicists, top quark, music, and stuff like that. And it got a certain cache to it, which went on for years and years. Okay, whatever, but it started to attract interest from a bunch of different organizations that were responsible. They were stakeholders for these collections, like the Smithsonian, like the National Archives, like various other museums, libraries, collectors. So, since that time, it's been like 20 years now, almost, and the project has just continued to grow and take on a whole bunch of interesting challenges. I would say, in some way, two of our -- well, there's been a lot of highlights, but we got to restore the sound of the earliest recording of a human voice, of the earliest recording with Thomas Edison's early machines, recordings of Alexander Graham Bell, we did a project a couple years ago where we restored 3,000 recordings of Native American song and languages from California, from the early 20th century, and we just got a grant which we need to find a match for to restore all of Alexander Graham Bell's research from the early 1880s, which is like hundreds of recordings. So, it sort of became a second parallel life along with all the particle physics stuff.
Carl, was there any issue with justifying this work, because of course, the Lab is part of the DOE, and there's all kinds of approvals and requirements in terms of the scope of work. Did you encounter any questions about this?
That's a good question. I would say, some colleagues were a little bit like, well, any time that you spend on this, you could be spending on something else. People always say that, no matter what you do. Well, you could have done more on something else if you'd not done-- there's always that kind of criticism that goes on. I would say the Laboratory was extremely supportive, and I think it's a credit to the open mindedness of the Berkeley Lab, management, the various leaders of the divisions, the associate levels, and even the Lab upper management, that they see the importance of taking ideas from one field and then transferring them, perhaps benefitting another. So, they were very, very open minded. The DOE was, I would say, nothing but supportive. I mean, the DOE did not put money into this. All the money that we spent, paying for people's time, travel, equipment, it all came from grants that we brought in from other agencies. Mostly government agencies. Close to $2 million over the years. We got money from the Library of Congress, we got money from the National Archives, we got money from the National Endowment for the Humanities, we got money from the Institute of Museum and Library Services. All these different funding agencies have supported this. In order to do this, they need to make official agreements with the DOE. There's a whole process when two US government agencies work together. There's a process, and DOE signs off on it, they sign off on it. So, everyone's been extremely supportive of it. I mean, it hasn't taken over. It's not our industry. But look, if you go on the DOE Office of Science website, the DOE lists, I don't know, 75 things that DOE science has done. Batteries and cosmic expansion, and this is one of them.
Yeah, that's right.
So, I always felt, if this is going to be on the DOE's website, probably they're okay with it. I think there are other laboratories that wouldn't have tolerated this. I gave a talk about this once at another laboratory that's not really an Office of Science lab. A different lab. And there was a guy in the audience that was just like, “Why would you do this? How did you justify this?” He was just -- what's the word?
Incredulous. He was incredulous that this could be. But the Berkeley Lab has been great about it. At this point, it's kind of like part of the brand. It's also listed as a Berkeley Lab innovation.
Carl, obviously, it's a huge win from the PR perspective, but given the fact that you've been asked this question, it seems like an obvious thing. What have been some of the greatest intellectual satisfactions working on this project, specifically, as a physicist? Why is this good physics as a project?
Well, okay. So, there's a couple of answers to that question. It's clearly not physics, in the sense that we're discovering new physical laws, new particles, new physical mechanisms, as would be done in mainline physics research. It has led us to a new toolbox of measurement and analysis techniques that we have been able to apply back to our work on building particle detectors. For example, using exactly some of the same software and techniques we developed for doing these very large data sets on scanning records, we built a machine that we use very, very often for taking precise measurements on some of these very large assemblies for the ATLAS upgrade project. Essentially, it's the same code. We just set it up differently. So, one of our-- let's say, the techniques that I like to say that we've really learned how to use in the last 20 years, technically, would be called metrology. Measuring mechanical stuff quantitatively. So, in that sense, this is optical metrology. We happen to be applying it to phonograph records, but same suite we now apply to other things that we need to measure in the lab. Now, over the course of this audio work, we started out with just microphotography, and just photographing the grooves. But once we learned more about how early sound recordings work, half of them use depth as a way of encoding the sound, and the others use lateral movement. So, in order to measure depth, we couldn't just take pictures. We needed a 3D imaging technique. So, there's a whole bunch of 3D imaging techniques, and we studied them. And we found that a particular one, which is called confocal microscopy, widely used in biology, would be the most appropriate one. So, we acquired confocal microscopes through the grants, and we learned how to use them. So, now, we have a lot of capability, software and hardware, for doing confocal microscopy on these phonograph records. All the Native American recordings were scanned with confocal microscopy. But now that we have confocal microscopy, it's also been back applied to some of the particle detector work that we do. And recently, our colleagues down the hall, who are building large microwave detector arrays for cosmic microwave background stuff, they brought their lenses to us, which are tiny little-- they're kind of lenslets. They're kind of little bumps, to scan them and get precise curvature measurements that affect the way they focus microwaves. So, whenever you acquire a measurement tool, and the knowledge of how to use the data and analyze it, you can often find that there are often going to be other things that you formerly couldn't measure very well, and now you have a really good ability to measure. So, I think that has been a benefit, that at least in part -- if you're looking to justify, right? Now, the other thing-- but there are other intellectual discoveries, or realizations that we made. For me, I might have figured this out if I'd just thought about it, but kind of playing in the same sandbox with Alexander Graham Bell, and Thomas Edison, and those people, you really feel like you get to look over their shoulder. I've seen their logbooks, and I've seen the things they've built with their own hands, and I've understood the challenges and the choices they made. It's very interesting to see how science and particularly technology was carried out in that period. Those people were not college educated. They didn't come from the analytical tradition of a Hermann von Helmholtz, or somebody like that. Europe was just bubbling with deep mathematical insight into sound, and light, and electromagnetism at that time. And in America, they were melting wax, and threading screws, and making these inventions kind of by the seat of their pants. I don't see any evidence that they calculated much of anything. Yet, they invented most of the technologies that are the basis of the 20th century information world. Bell, telephone. He perfects the phonograph. Edison. By the way, Bell also built a technique for transmitting data over light, called the photophone. Samuel Morse, telegraph. He basically invented coding. Okay, the French. They did photography. Gotta give that to them. Eadweard Muybridge, the idea of the moving image, that you could capture images, American. Completely out of his mind, but -- these people were so iconically American, almost in the Steve Jobs sort of a way. They just kind of like winged it. I don't even know where these guys come from. They just sort of dropped in from nowhere. So, I think it really kind of helps you appreciate what the American spirit of innovation is, or was. It's easy to romanticize it and make up stories about it, because now, of course, everybody who works for these present-day companies, pretty much, are rigorously educated, and are using powerful analytical tools, and all of this. But I think it's important to appreciate that America, much more than any other place, I believe, has this very innovative, almost cowboy way of doing technology, and to some extent, science. Ernest Lawrence, to some extent, was part of that same-- of course, there were other dimensions to Ernest Lawrence. Oppenheimer, no. I believe he came from the European tradition. But it's fascinating to see how all of that came together. I think it's educationally really valuable to see that. Another thing is, which I had no idea about, and now I more appreciate, is the earliest adopters of these techniques, of sound recordings, they were basically linguists and ethnographers. It wasn't the music business, or even business dictation, which is kind of what Edison thought. Oh, this will be great for business dictation. There were a whole bunch of these people that went off immediately and started recording languages and cultures that they knew were not going to survive. That was really visionary, too. So, there's a very interesting convergence of stuff that's going on late 19th, early 20th century, that is known. You can read about it if you want to, but I don't think that narrative is super well appreciated by the public.
Carl, totally speculative, forward-looking question, but it's irresistible to ask you specifically. For these interviews, I record on an external device. I have a memory card that goes into my laptop, saved to the hard drive, uploaded through a VPN to the cloud, where we have our server. We back up on a terabyte external hard drive, and the Niels Bohr Library also backs up through Iron Mountain. Right? We're good. Now, for you to extrapolate, thinking about your experiences saving Alexander Graham Bell's voice, let's fast forward 128 years into the future. What kind of confidence, or alternatively, what weak links do you see in the recording system that I just laid out to you, that this discussion, not just the paper which we'll print out for the archives, but the audio from this discussion will be accessible to future metrologists, or whatever we might call them, into the 22nd century?
So, this is a good question, and it's one of the questions that's kind of front and center to folks at the Library of Congress, for example, that we talk to and work with to this day, including Peter. So, one of the things that the Library and other institutions do is they look at the reliability and the longevity of media. So, if you end up archiving on CD-ROM, or on hard disks, or whatever, one of the things they're going to want to know is how reliable that is, how redundant does it have to be? So, presumably, any responsible organization will backup, will have multiple copies, they'll be redundant. So, for example, in the project we did with the 3,000 Native American recordings, it was managed by the University of California at Berkeley Library, and they dealt with these issues with multiple memory boxes, and that sort of thing. But you know, your memory box, your hard drive, whatever it is, is going to be obsolete at some point. So, they're going to have to copy all the data onto something else. And that will go obsolete, and then it will be copied onto something else. The thing is, as long as you keep copying, if it's digital, then with error correction codes, you have no problem that the copies won't be genuine. Analog media, the media that Alexander Graham Bell and all those guys used, as soon as you play it and re-record it onto something else, it's getting degraded. So, that's the weakness of the analog media, which the hipsters would claim has better sound. But the digital media, as long as it's a responsible organization, they will continually copy it to the next generation of materials, and they don't have to worry that the copying process will be lost soon. Obviously, if you were to be using a lossy type of encoding, that's different. There's a really great book that deals with this whole issue called When We Are No More. It's by Abby Smith Rumsey. She worked at the Library of Congress. I know her. She also worked at the Council of Library and Information Resources. She's one of the people that kind of dealt with a lot of these policy issues around media and preservation. Brilliant person. She talks about the past of the preservation of information, the history of libraries, and then going into the future. What are some of the issues and ideas and problems around exactly what you're asking? I don't think it's an unsolvable problem. Yeah, there might be some hard drive that gets dug up in a landfill in 100 years, and somebody would be like, what is this? I kind of think that with modern technology, if it's a magnetic or optical medium, and it's digital, they can put some microscopes and lasers and things together and probably scan it. But older things? Now, that's another story.
When the MacArthur Foundation called, was that totally out of the blue?
Yeah, you don't get any warning about-- the whole thing is a secret. You don't know when-- I mean, presumably, they're doing research and they're talking to people and asking for letters, I imagine. They don't actually tell you what their process is, but I know about admission processes to universities, and I've been on awards committees. You have people, and they get letters, and it's all supposed to be confidential. So, yeah, that's all a big secret, and then they call you.
What did it feel like to be named the MacArthur Fellow?
I knew it would make my mother very happy. Frankly that was-- telling my parents was probably the best part.
Sure, “My boy's a genius.” [laugh]
Well, that's not what the MacArthur Foundation says. That label has been put on it by the media. But, you know, obviously, it's definitely a nice thing. I totally recommend it. And you get to meet some really interesting people, because they do Fellows Forums, and you go and spend three days with just a whole variety of people from many different fields, folks that you'd never expect you'd meet. Some that you would. I got to have lunch with George Zweig, who you may have interviewed. I don't know.
He was one of the guys who-- he called them “aces”, but it was the quark. And then, you know, other people like Ben Katchor, who is a famous cartoonist, I never would have thought I'd get to meet him, and I got to hang out with him. So, that part is really fun, and people maybe give you a little bit more benefit of the doubt, I guess.
I'm amused that on the MacArthur Foundation website, your title is listed as Audio Preservationist.
Well, because that's sort of the way they-- it's up to them. It's their money, right? They can define me any way they want, I suppose. But, yeah, if you look at the history, a little bit, of the awards, they don't give awards in every single field. But preservation is definitely an area that they're interested in. There are paper conservators who've been awarded the fellowship, and people that work on architectural stuff. There are definitely areas of focus that's very important to them.
Carl, just to bring our conversation up to the present, in the past two years, what have been some of the big things that you've been working on?
You mean, overall, or specifically in audio?
Right, so, as I said, round about the time that the Higgs particle was found, there were plans to improve the collider, make it a brighter machine and have more interactions. That was going to happen in the 2020s. So, we started to work on these ideas that, as I said earlier, kind of had their legacy in some of the stuff we did at Fermilab, to create kind of a new technical implementation of precision trackers. So, through the 2010s, into the first half or so of the 20-teens decade, we were doing a lot of—I and my colleagues—were doing a lot of prototyping around proving that this new idea could work. It was basically a way of integrating the electrical, mechanical, and thermal requirements into a super lightweight package of stuff that would work really well together, and allow a much larger detector to fit in the same volume. So, that was a pretty exciting time, 2010’s or so, because I think we had a lot of early success with this concept, and it was adopted as the baseline design of the tracker. So, there was really a lot of satisfaction around that, seeing that idea be embraced, and now it's like, hundreds of people are working on it. Most of it, we cooked up at Berkeley, on some of the basic idea of how to do it. So, that was really exciting to see. I would say, around 2015, the project was turning into a major DOE funded initiative, which now implies a lot of oversight, and management stuff around the cost and schedule, and all of that. So, I got involved in that around 2015, much more deeply involved in some of the project planning and project management aspects of this thing. The whole upgrade is hundreds of millions of dollars, and this piece that we're working on is like $40 million just in the USA, so that was enough that you really have to be working closely with the agency on milestones, and goals, and deliverables, and all of that. So, between 2015 and 2020, we kind of put that whole thing together in a form. It went through many high-level reviews with DOE, and different committees, and stuff like that, and it did really well. It got past these things. So, at this point, the project is very much on—I think a reasonable—let's say, the pandemic-- I still don't completely understand what the effect of the pandemic is going to be on schedules, and funding for the future. So, there's a huge cloud in front of everybody, I believe, who has anything in their lives that has to do with business or the government. Like, how do we emerge from the pandemic? So, I can't address that, but setting the pandemic aside, which is not easy to do, the project by early 2020 was in pretty good shape, and looks like it's fundable, like it's buildable, and all of that. My project management related activities stopped around that time, and I started diving much more back into the lab work around the stuff that Berkeley is specifically responsible for making. I'm ambivalent about the whole management way these projects are managed. I think it's quite inefficient, but it's a necessity. There's no question that when you're dealing with that kind of money, and government stakeholders and the taxpayer, everything has to be done in a very transparent, highly reviewed, structured way. But I think the process could be made much more efficient. Having said that, I think the project was done okay. But I wasn't doing management anymore around the time the pandemic started. I switched back into much more of a technical mode, and am pretty happy with the way that's been going. Recently, I started talking with a colleague about a new idea having to do with a different kind of semiconductor that we might be able to use in an interesting application. So, I'm kind of excited about that. If you ask me in a week, I might discover that there's a flaw in that idea, but I'm pretty happy right now, because there's a bunch of interesting technical problems. And then, on the audio side of it, in 2019, the Smithsonian was awarded half a million dollars by the National Parks Service to undertake a project to restore hundreds of recordings and experiments that Alexander Graham Bell did that we haven't touched yet. We got to work on about 20 of his recordings around 2015, and it became a really nice, year-long exhibit at the Smithsonian. But there were hundreds left that we didn't get to work on, because it was pilot. So, now, the National Parks Service, they have a program called “Save America's Treasures”, and they gave us half a million dollars to restore the rest of that collection. But it requires a match from a non-federal source, one to one. So, we had that money all lined up from Canadian interests, because the Canadians-- Bell first lived in Canada, and he spent about a quarter or a third of the year in Canada, in his house in Nova Scotia, and he did a lot of experiments in Canada. A lot of his early sound recordings are still in Canada. So, we were going to do this international project, and the Canadians were going to put in half the money. But with the pandemic, that just collapsed. The Canadian funding sources became much more concerned about economic, let's say, safety nets and stuff, in Atlantic Canada, and everything just became really murky. So, there's negotiations going on, and maybe the Canadians will come back. We don't know, but right now, we're looking around for another donor to provide the match. We have some leads, and we have some folks working on our behalf to see if other donors could be found. The Parks Service is pretty cool with it, because the Smithsonian's been closed for a year. So, everything is just on hold, and the Parks Service is just like, “Okay, don't worry.” We've got more time to line it up. But if we got that money, that would be a really great project that would go on for the next three years. We'd set up the whole scanning laboratory at the Smithsonian in Washington, in the National Museum of American History. There'd be public engagement, there'd be an educational component, and I don't know if it'd end up in another exhibit, or what, but it definitely would make public access, scholarly access, to this collection very, very easy and facile. So, that, I'm excited, but worried. It's hard to drum up half a million dollars, but there's also lots of people that have that kind of money.
Carl, we've worked right up to the present, so for my last question, we'll wrap it all up with a really big one.
Obviously, over the course of your career, the ability to do all of the different things that you've done, the fact that you're at Berkeley is really central to all of it. So, what's been most meaningful to you about being at Berkeley all of these years, and how might some of those advantages and opportunities translate into the kind of science you want to do into the future?
So, Berkeley-- it's hard to imagine a better place to be. It's like, you have the best of not both worlds, but many worlds. You've got a university which is incredibly broad, and obviously has people who are distinguished in many, many fields. You've got incredible collections. You have a history in anthropology, in physics, in electrical engineering, in computer science, in particle detectors, in particle physics. Basically, you've got some of the best of all of this in one place. Berkeley Lab, it has-- as I said earlier, we're talking about this great tradition of trying out new ideas, innovative research, and a willingness to confront societal needs in one way or the other. I mean, it's perfect for mounting these kinds of things, these kind of projects. Be it particle physics, or audio preservation, or something else, the human genome project, or better batteries, dark matter, dark energy, all of these-- it's really amazing that all of these things can be under one big roof. The facilities of the Lab are ideal. We've got incredible machine shops, and electronic shops, plus we're in the Bay Area. We have access to all of that technology in the whole Silicon Valley, Stanford, that whole community. It's very collegial. You could have a really wonderful place, and you put a bunch of really difficult people together, and you know, the whole thing just could become poisoned. It's not like that. It's a great mix of people, and they get along well, and they're supportive of each other. The older generation -- look, now I'm probably the oldest person that is not a retiree who's in the Division. I think I've been here longer than anybody who's not retired, except for maybe one. But you know, the older generation, they're all still coming in. So, we got brought up by-- some of them, obviously, sadly, have passed away in the last couple years. George Trilling, I'm thinking of. But when I came, George Trilling was maybe my age now, and he was the Director of the Physics Division, and then Pier was the Director, then Bob Cahn, Jim Siegrist, and now Natalie Roe. These people, you could go into their office with an idea, and you could walk out with, whatever it is, a certificate to go ahead and do this. They could take the initiative, they had the flexibility to make the quick decision, and give you support. Fundamentally, things always get more complicated and more bureaucratic as time goes on, and the agencies get more bureaucratic. But we still have, I think, enough flexibility that if you come up with a new idea, and it's compelling, people will find a way to get you jumpstarted. Yeah, so, Berkeley, I've obviously interviewed tons of people who have been applying for jobs here, and trying to convince them to come, and I think many people -- I think about a younger colleague here. I come into his office, and he's like, “I can't believe I landed here. This is incredible.” It's everything he ever wanted under one roof. And I definitely felt that way, too. And the food's good, too.
Carl, it's been a tremendous amount of fun spending this time with you. I want to thank you so much for doing this.
Oh, sure, sure. I was really flattered when I heard that you guys wanted to do it. Thank you again for this opportunity.