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Credit: Alan Stivers
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Interview of Piero Pianetta by David Zierler on October 2, 2020,
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 Piero Pianetta, Research Professor in the Photon Science Department, joint with Electrical Engineering, at Stanford. He recounts his family’s Italian heritage, and his upbringing in Italy and then in California. He explains his interest in pursuing physics as an undergraduate at Santa Clara University, and his graduate work at Stanford where he worked on monochromator experiments and contributed to the SPEAR collaboration at SLAC. Pianetta discusses his scientific interests converging on surface science and the influence of Seb Doniach on his research. He describes his postgraduate work at HP where he focused on laser annealing and subsequently SSRL to conduct research on device technology and photoemission techniques. Pianetta explains how SSRL became integrated in SLAC and how he became administratively housed in the Photon Science department, and how this development is illustrative of the way SLAC has diversified its research and redefined its relationship with the Department of Energy. He describes his most recent responsibilities as chair of the photon science group at SLAC and his current work chairing the laboratory promotions committee. At the end of the interview, Pianetta reflects on the long-term impact of remote work for SLAC generally and he conveys optimism on improving SSRL’s long-term capabilities.
Okay. This is David Zierler, oral historian for the American Institute of Physics. It is October 2nd, 2020. I am so happy to be here with Doctor Piero Pianetta. Piero, thank you so much for joining me today.
Yeah, thank you.
All right, so to start, would you please tell me your title and institutional affiliation?
I'm a (research) professor in the Photon Science Department joint with Electrical Engineering at Stanford. I'm primarily based at SLAC. Which are where most of my administrative appointments are, and my research lab.
Now, do you have graduate students through SLAC or through the university?
Good question. [laugh] That's a good question. I have graduate students and I've never thought about that. I mean, basically, a graduate student will come to me and I'll sign them up. So, the administrative part gets taken care of through SLAC, because for the most part we pay them through the SLAC contract. I have funding that comes through campus as well that gets submitted through the electrical engineering department. And in that case, the students would be taken care of by the administrators in Electrical Engineering. So it's really-- they're Stanford students and then where they come through is really kind of the bureaucratic part.
Which administrator takes care of the paperwork.
I ask because I've developed-- I'm keenly attuned to some of the tensions that arose between SLAC and the department of physics. And of course, that's 60 years ago, but administratively, there are still these issues to work through.
Yeah, it's changed a lot. So for instance—maybe we'll probably get to this later—but I came to SLAC through campus connections, because when we started developing the facilities at SLAC, I worked as a graduate student, I worked for people who were Stanford professors, not affiliated with SLAC. And we were an independent laboratory of Stanford University. And so, when we went into the DOE fold and joined SLAC, we connected with campus in a very different way. And you may also be aware that there were some tensions in the campus physics community that led to the formation of the Applied Physics Department which was oriented towards solid state physics vs atoms and nuclei. I was actually an applied physics graduate student and there was a distinction between the departments. Nowadays, the two departments are still separate, but they've come together in quite a few ways, so those things, 50-60 years ago, have made a lot of difference.
Well, Piero, let's take it all the way back to the beginning, and I'm particularly intrigued by your name and your very American accent. So, let's start with your parents. Tell me a little bit about them and where they're from.
My parents are both from Italy. My father came over here in the 20s. He got out of the Italian army after World War I and went into the railroad for a while in Italy.
And where in Italy were your parents from?
So, a place called Voghera, which—V-O-G-H-E-R-A—which is close to Milano, very close to Pavia. And so, I think he was waiting for some sort of promotion in the railroad, and I guess it came through, but he had already decided to go to America. And so, he came over. There were two listings in the Ellis Island Foundation. And I think he missed the first booking and came on the second one. So, he got here starting 1920 or 1921. And then came to California, because his brother was already here. They worked as farmers in Bay Farm Island, which is now Alameda. And then a bunch of them got together, bought land in what's now San Lorenzo, and farmed there until the late 40s.
My father had a farm in Italy too, and he was always trying to figure out where he really wanted to live, and so he went back and forth. I think, right as World War II broke, he was in Italy and so he snuck out through France and came back to the US. He continued farming but he was too old to be drafted into the U.S. Army. So, he stayed working. And then he went back to Italy after the war, got married, then came back here in the late 40s. I was born in California. And then we went back when I was I think two. We went back to the farm and his sister at that time was living in his place. Stayed there for a few years, came back here. I did kindergarten and first grade in the US, and I learned English in kindergarten.
Oh, so Italian was very much your first language?
Yep. And then we went back and I kind of did second grade there, in English. My parents brought schoolbooks from the US, and so I did second grade in English. And at that point, my father was trying to decide whether to stay in Italy or go back to the US. He had heart problems, and the weather there is kind of like Buffalo, New York. And so at that point he said, “Well, I can't live here,” in that area, and so he said he'd have to move to a more temperate climate on the coast or something, and so he said, if I'm going to do that, I'll just go back to California. And so that's when we came back, and it was like 1958.
I wonder if one of the stories behind your name was that, your first name, was that perhaps your parents were thinking that you would grow up in Italy?
I don't know. I think that since we spoke Italian at home, they just dropped a T from my father's name, and that turned into my name.
[laugh] I see.
I don't think there was anything particularly deep there. But one of the fun things was that on one of the trips, we actually-- and I think it was probably the trip to Italy, the last trip to Italy. We went on the Andrea Doria, which a few years later sank. And we were waiting for it, we were going to take it home, back to the US, but it never made it back to Italy, so then we had to scramble and find a different boat. Because we never flew. It was all ships and trains from Genoa all the way to California. That's how my father did it. He never flew on an airplane.
So, you know-- I think in, yeah, in two days, my father would have been 120.
Wow. Wow. And Piero, where did you grow up? Where did you spend your formative years?
I was born in Santa Rosa, then moved to Italy for two years. When we came back, we lived in Hayward where I attended kindergarten and first grade. We moved back to Italy where I went through second grade. We then came back when I was eight years old and lived in an apartment above my uncle’s garage in the East Bay and then moved to Fremont. By that time, my father had retired from farming and my cousins and uncle continued farming, but they moved to Fremont which led to our moving there. So that's where I grew up which was good, because I had summer jobs on the farm for quite a few years.
Piero, did you-- were you interested in science from an early age?
I liked to read. I actually was interested in zoology when I was a kid, reading about animals and things. And then I liked to build things. So, I'd go to the library to find drawings of real boats that I could scale to a convenient size and then build. And so, I always liked to build things and tinker, and I guess that's what led me into a technical direction. I wouldn't say I was analytical, but I was more of the hands-on type, which I've continued to be.
So, experimentation was an early indication for you?
Yeah, in fact, one of the times we were in Italy my parents were having some sort of party. I was playing with hot water and noticed that the temperatures of two things would equalize. My parents were far from scientific, so I never really took anything beyond that. I said, “Oh, look. That's what happens.” But that was about it. Nobody said, “That's the law of thermodynamics.”
[laugh] Piero, were you a stand-out student in math and science in middle school and high school?
I didn't have middle school, just grammar school and high school. And I would say in grammar school, no. I did okay. It was never obvious to me, that I was doing particularly well in school. Then when I got to high school, that's when I noticed that I was doing well in school. That I could do things. We had science class and then we had physics, and that's when I got interested in physics, I would say.
When you were thinking about college, were you thinking specifically about physics programs?
Yeah, I think so, because at my high school, we were introduced to the physics department at the neighboring college, and there were three of us who had similar interests and hung out together. We all went into physics at the same school.
Uh-huh. I'm not very familiar with Santa Clara University. Can you tell me a little bit about it?
So, it's a Jesuit university. It's small and more of a liberal arts college. There's a lot of emphasis in that. The physics department had half a dozen faculty. They had a good physics and chemistry and biology department, but they were pretty small.
I imagine in the late 1960s, it was probably a much quieter place than a Berkeley would have been.
Yeah. In fact, you would get the feeling that it would sort of suck the life out of any demonstration. Pretty quiet, I would say.
[laugh] Yeah, yeah.
It probably had a bigger engineering school. And I think it still does. And it has a good law school—it was kind of the local law school where a lot of the local lawyers come out of. And yeah. It also had a good math department.
You could probably develop good relationships with the professors, if you wanted to.
Yeah, yeah. They had good relationships with NASA Ames, so we got internships there. I would say about half the professors had some active research going on, so one of my friends and I worked for one professor for our last two years doing low temperature physics.
There were no graduate students, so we basically helped him build apparatus. We built an NMR system from scratch to use as a magnetometer. Our professor was an electrical engineer before going into physics, so he would guide us along, but we got to do a lot of building of apparatus.
Piero, given your interest in experiments and applied physics, at what point did you determine that you wanted to pursue graduate work in physics and not go on to a career in industry?
I'm not sure if or when I thought about industry. I never thought about semiconductor physics at the time. We did take electronics classes and so I knew all about it and could work with it, but I was thinking that biophysics would be an interesting area. I think that's one of the things that led me to graduate school. I applied to five schools. There was Berkeley, Washington, Illinois, Stanford, Santa Barbara and Davis. The thing that attracted me to Stanford, in particular applied physics, was a professor, Mitch Weissbluth, who was known for doing biophysics. He had done I think some imaging and did experiments using the Mössbauer effect. So I went and talked to him before applying, and I really liked what he was doing. And so, I applied because of that.
How long did that last? Your interest in biophysics?
It's still there.
And unfortunately, what I didn't realize being from a school with no graduate students, was that when a professor writes papers and only his name is on it, he probably doesn't have money to hire you. But they took me anyway, and in the applied physics department, incoming students are assigned to work for a professor while they look for a permanent group. I was assigned to work with an MD in the medical school who had an undergraduate physics degree but was a practicing pathologist.
At this point in his career, he had decided he was going to bring physics back into his research. His area was electron microscopy. So, I actually learned to do electron microscopy. We were looking at DNA. There were three other graduate students from applied physics in the group, and they were all working on different imaging methodologies. Because at the time, computers weren't that powerful, so they were essentially, Fourier transforming the TEM images using light, essentially doing Fourier Optics. I spent my first year working with in that group. I probably would have continued that work, because it was really pretty interesting, but since he was in a pathology department and not really doing pathology, so, when his funding ran out, his department basically said sayonara.
So, by the end of my third quarter, we were all out on the street essentially and looking for other advisors. One of my group members graduated, and one went to work with somebody studying the ear canal, and the third went to work for Cal Quate in applied physics who eventually developed a commercially viable acoustic microscope. And I was talking to different professors in bio related areas. I talked to Gilda Harris Lowe, who was Gregg Lowe's wife, although I didn't know Gregg Lowe at the time. She was a physicist who was doing molecular orbital calculations on biological molecules which was very interesting. I also talked to Harden McConnell's group, Arthur Kornberg and his group and Earl Shubert in the hearing program. […] I also went to see Ted Geballe because I knew him from classes and because I had done low temperature physics as an undergraduate.
This of course is when Ted was not 100 years old. [laugh]
Yeah. Yeah. He's still amazing.
Yeah. I have an office on campus and see him regularly when I’m there.
He does laps on the third floor of the McCullough Building. And he's great. We actually did some work together, probably ten years ago, on some electron emitters that he was involved with. And so, back to the story, he said, “Well, I don't have anything right now, but go talk to Seb Doniach,”—who's probably on your interview list because he was one of the founders of the synchrotron lab—and “he's trying to set up this lab, and he may have something for the summer.” So, I went to talk to him. He just recently retired, in fact. He's been active faculty teaching and doing research until this year. I think he will probably still going to continue being active. I mean, he's an amazing guy.
And he started telling me about the synchrotron lab and he was about to set it up. One of the projects was going to be angiography. And so that was like, wow, that's great, I'd like to do that. And so, then I started working with Seb. That summer my task was basically to go talk to the SLAC people and figure out what it would take to get the hardware put into place. The groundwork had already started, so there were people working on different aspects and there was some funding to build the part of the beam line to get the x-rays out of the machine. But somebody needed to talk to the facilities people to get the shielding moved around and set up everything else which included something so you could receive the x-rays.
And so, I basically-- I didn't know anything about accelerators or anything, but I went out, had a meeting, and it was in Pief's office. So, when I showed up, I was sitting outside his office. He came out and said, “Hello, what are you doing, what do you need?” And I said, “Well, I'm here for a meeting.” He said, “Oh, come on in.” And then the group of people showed up and basically, he just said, “Help him.” And that was it.
What year would this have been, Piero?
So, this was 1972.
At the beginning of the summer.
Right, right. The beginning of a lot of exciting things.
Yep. I was working with Jerry Fischer and Earl Hoyt. Earl was an engineer who did a lot of materials science related to accelerators. He worked for Ed Garwin. Jerry was more involved with the big picture of what should a facility look like and things like that. He was very, I would say, instrumental in moving the project along. Although I was involved at the ground level, I was not involved in all of the other higher-level discussions going on. I wasn't involved in those, obviously. Earl was in charge of developing the beryllium windows that let the x-rays out of the accelerator, and his machinist was actually carving the beam line out of stainless steel in the shop.
It was also early times, when you didn't have a local backing [of] companies that would just knock this stuff out. To design the beryllium windows, Doniach, who's a theorist, had set up a computer program to calculate how much power the beryllium windows would take. To verify the calculations, Earl designed an experiment where we took a piece of beryllium, stuck it in a vacuum chamber, and ran current through it to see when it would start evaporating in order to get a temperature and power. Then, Seb figured out that to keep it from melting from the x-rays that the beryllium would absorb on their way through it, you would need to put some thin foils of beryllium to absorb some of the power in front of the actual window. At that time, these absorbers would also be beryllium. So, I took his program, played with it, and we calculated how many foils and the thickness we needed.
And then, long story short, it turned out that the original way the foils were going to be made by Battelle labs was to plate beryllium onto copper, and then etch the copper away. None of these films held up. So finally, Earl figured out we could get graphite foils to use as the absorbers, and then we got another company (Brush Wellman) to e-beam well beryllium foils onto copper for the actual vacuum windows. So those were our beryllium windows. That was one big step because windows of that size had not been previously available. Then I continued working on the other parts of the experiment.
And then, about a year later, everything was ready, and we installed the first beam line. And again, it was done pretty much ad hoc. They took the shielding block on the SPEAR ring, turned it a little bit, added another concrete block perpendicular to where the x-ray beam would come out, and then put another block as a roof on it. So when we went to install things inside, the SPEAR ring, you may know, is built essentially on asphalt.
So, the asphalt was the floor of the alcove. To give me a floor to work on they just lowered in a piece of steel as a base, which turned out to be battleship steel. I spent the previous year building the monochromator for the x-rays. So, I basically designed it, machined some of it myself, and got help from some machinists to build the large plates. I did this all in Hanson labs or Ginzton labs using Mitch Weissbluth's lab. Because he was interested in using the synchrotron and he and I were still talking about possible projects that I might work with him on synchrotron-related things. So he made room in his lab for me. And another fun thing is, in the machine shop, there was somebody who had retired from Bell Labs named Walter Bond. He had invented the double crystal x-ray monochromator, for developing quartz oscillators for radar which was exactly the monochromator I was building. He was also a fabulous inventor. At that time, he was working with the acoustic wave researchers, developing ways to polish round edges for acoustic wave propagation on crystals surfaces and all sorts of crazy things. I was lucky to learn machining from him.
I finished building and testing the monochromator on campus and brought it to SLAC to install it. To install the monochromator, the concrete slab roof was removed from the alcove and the monochromator was lowered in with a crane. I had built some pedestals that I welded up out of pipe. When I went to drill the holes to mount them onto the battleship steel base, I realized that the drill wasn't drilling, since we only had about an hour left before they were to put the roof back on, so some of the guys ran and got me some five-minute epoxy, and so we just epoxied the bases in place.
Piero, where is all of this fitting in with your sort of overall graduate education? I mean are these like side-by-side or is it all one integrated endeavor?
It's all together.
Because I'm taking classes and I'm doing this, which in the end, it resulted in experiments that went into my thesis.
So, we successfully put in the beam line. In parallel to my working on the monochromator, Ingolf Lindau, who's probably also on your list of people to talk to, came into the project at about the same time. I as a graduate student, he as a postdoc. And he worked with [Bill Spicer] as a postdoc. Seb and Bill were jointly founders of the lab and so they put me with Ingolf, because he was going to set up the chamber, the experimental chamber that the monochromator would feed.
And so basically, my job was [to] build the monochromator. His job was [to] build the experimental chamber. This chamber went into a steel hutch attached to the alcove where the x-rays would enter. SLAC facilities simply drilled a hole through the alcove’s transverse wall to match a hole in the hutch wall. I worked with them to work out the concept for the hutch and SLAC facilities (I think it was […] EFD at the time). So, we ended up with the hutch, sitting outdoors, attached to SPEAR ring. And inside was an ultra-high vacuum chamber with an electron spectrometer. This experimental configuration came about because the rules were that all of our hardware had to be separated from the vacuum in SPEAR. Also, to simplify radiation safety the hole through the concrete shielding would need to be one foot below the SPEAR ring electron orbit so that neither the electron beam or too much radiation could get out.
And the rules, this is like Ralph Young who is imposing this? For safety reasons?
This was for safety reasons and I forgot who it was, but it wasn't Ralph Young. But it was somebody in the safety office.
And so basically, we had these boundary conditions. Since we were going to do a photo emission. And we're going to do-- we need[ed] to do high resolution photo emission at eight kilovolts, we needed a high-resolution x-ray beam. And so, my monochromator had two crystals plus another fancy crystal that would bounce x-rays three or four times before the beam got out. I learned how to do by being in contact with Artie Bienenstock who also funded me for some of my graduate school at that time, because nobody had money. He was interested in in the project and would suggest people I should talk to. So, I ended up calling people like Bob Batterman at Cornell, a big-time professor, and I would just call him. And he would talk to me and teach me about x-rays over the phone. And Dick Delattes, who was another one of Artie Bienenstock's friends, did the same thing. He would send me information. And then Gene Myron, who was at Fairchild, and later became an Intel fellow. I went to his lab and he gave me parts since he was redoing the spectrometers in his lab, so he said, “Here, take the old one.”
And then there was a guy from Aerospace Corporation—all of these people were Artie’s friends—his name was Nikos Alexandropoulos, if I remember right. And he showed me how to hold x-ray monchromator crystals so they wouldn’t deform and how to do other practical things. So, we put all that together into a spectrometer. Fortunately, we didn’t need the third crystal, otherwise never would have gotten very many x-rays through the monochromator just because the properties of the machine were not like today, where very parallel beams can be produced. But it turned out that when we did our first experiment we only needed the first two crystals—
So the hardware was essentially outdoors. For the control station, I rented a trailer and had to put it probably 30, 40 yards away from the experimental chamber because they were going to pour a concrete slab for the new lab next to our experiment. The SLAC people ran the cables for us, and we were sitting in the trailer running clock motors to make the crystals align. And this was all done remotely, because we couldn't go into the monochromator housing since it was in the storage ring. For months, basically. And so, we got the crystals aligned, got a signal, and it turned out that the resolution with two crystals was what we needed. Then we did the photo emission, which was also difficult because the analyzers weren't designed for such a high x-ray energy, so we had to put 5,000 volts on the sample to slow the electrons down. And we got it to work, Ingolf was collecting the spectra at probably 50 counts a minute. 40 to 50 counts a minute, not a second. And so. it really was like a high energy physics experiment from that point of view. And we got really narrow signals. Very narrow peaks. Indicating that our resolution was really very high, much better than what we expected.
And so then, as I analyzed that part of the experiment, I realized that the electron beam in the ring—and I didn't know anything about electron beams in the accelerator—must have some properties that I had not realized when designing the experiment. I started talking to Andy Sabersky, who had worried about these things for SPEAR, because he had developed some optical monitors that were being used on SPEAR. He taught me about phase space, and I realized that it was the phase space of SPEAR combined with the phase space of our electron analyzer, that gave us the high resolution. And so that became a chapter in my thesis as well. And so, we had met the goal of measuring 4 f levels of gold at high resolution and combined with the analysis of the phase space it because chapter one of my thesis. And it was Ingolf who wrote our first paper as a Nature paper on the very first experiments. So that got me started in, not biophysics, but in surface science.
Yeah. Piero, I want to zoom out with two sort of broader questions at this point. First, what was the relationship-- why the connection with SLAC? What was going on at SLAC that would have made this research relevant to the sort of broader mission? And then with surface science more generally, how was your research at this point sort of responsive to some of the larger questions that were going on in the field at the time?
Okay so two things. One was that Bill Spicer heard about the SPEAR synchrotron at SLAC. And so, he wrote a letter to Panofsky and Richter saying that this is an important new area, that using x-rays from a storage ring would be an important for the study of materials and physics. And so, he asked them to put a port on the SPEAR ring, which Richter agreed to do. That would allow x-rays to be extracted from the ring. Spicer also had some connections with Stig Hagstrom, who was in Sweden at the time and was involved in x-ray photoemission. He later came to Stanford. He's dead now, so he may not be on your list, but he's one of the names that figures prominently.
The idea of doing photoemission started then—which is one of the things Spicer pioneered—he felt would be very important and could be well-served with the storage ring. So that's how it started. And then, the bigger picture—at least concerning what we were doing—was that at the time, Kai Siegbahn in Sweden was doing electron spectroscopy for chemical analysis. This was the acronym he coined, ESCA. HP took his designs and actually built an ESCA machine, which they were selling commercially. And so, there was the promise that this new spectroscopy would open up a lot of doors for chemistry and physics for the study of surfaces and interfaces.
So, there were two aspects to what we were doing. One was that we had to design an experiment that could be done within the parameters given to us by the SLAC. We could have designed other experiments, but this one was chosen because it could be used to demonstrate that you could use XPS, x-ray photoemission spectroscopy, or ESCA to probe very detailed spectroscopic structures by going to very high resolution. And up until then, the resolutions that people were getting were pretty poor compared to what we thought we could do. At the time, we essentially had the record for resolution, and we were able to do that. It wasn't very easy, it was pretty hard, but nowadays, people are building beam lines that have better resolution, actually have practical counting rates, and are used for probing subsurface features. And so that was kind of the first synchrotron experiment that proved the point. And the fact that it was successful also contributed significantly to NSF deciding to fund the facility at Stanford—the synchrotron facility.
And so we needed, for instance, that one paper to be able to say, “Okay, we can actually make this work.” And so that happened in ‘73 after we got our first data. And at the same time, Doniach was writing the proposal to NSF, and Harvard was the competing proposal. And so we got the funding here, and by the end of the year, going into ‘74, people were-- I actually know what the dates are but I don't remember them, you know? I actually wrote something up that has the dates, that ended up in Journal of Synchrotron-- Not Journal of Synchrotron Radiation, but Synchrotron Radiation News. And I wrote a couple of articles like that. But basically, by the end of that year, I think, we had to pull out our experiment because they were starting to build the building around us. So, that was both the practical big picture and then the research big picture.
Right, right. Who were some of the key collaborators among your peer group? Other graduate students that you were working with at that time?
Brian Kincaid was one. While I was building my hardware, my electronics hardware, and Ingolf was building the chamber, Seb Doniach hired Brian. He had been a graduate student for a while, because he started out working with Bill Fairbank on an experiment that he got the basics of the experiment to work, but the physics wasn't working. So, then he went to work with Melvin Schwartz, but the accelerator they were going to use didn't get built. And he wanted to finish. He was a physics student. Bill Fairbank's students were famous for taking nine years, ten years to get out because they were always doing impossible experiments. So, Seb told him, “You'll get out in a year if you come and help us get the EXAFS experiments going.” Which was part of the funded facility.
And so, Brian started while we were still building up, before we did the basic experiments, before we had the money. And so, he taught me electronics, because he was like a genius at this stuff. He helped us build up the electronics that we needed for the vacuum chamber. And then when the facility was built, he was the one who worked with Peter Eisenberger from Bell Labs to build up the EXAFS experiment. So he was one, and he was very important. And then another graduate student who was working with Artie Bienenstock on EXAFS related things was Sally Hunter, who's now known by her maiden name, Joan McColl. And so, she and I were basically working in the trailer building up stuff. And then she was involved with the first EXAFS experiments. And so that was it.
At the very beginning.
And beyond the first chapter, did you see surface science as sort of like, where everything was headed for you in terms of not only the rest of your dissertation, but your identity and how you wanted to build a career?
Yeah, after a while. When the facility was built, there were [counts] five stations that were built on the one beam line. Two of the stations were for doing soft x-ray spectroscopy. And one was a very low-energy monochromator where you could do surface science and photoemission. And the other one was a higher—slightly higher energy range—but still all in vacuum. It was below 300 eV. That's where you could do surfaces. And by that time, we had moved our chamber to this beam line and did some preliminary experiments. And it was clear that if you knew how to do something at 40 counts a minute, when you had a few thousand counts a second, you could actually do work.
And Bill Spicer at the time he was like one of the gurus for surface science. And we were starting to work on gallium arsenide, what he was doing was trying to understand the surfaces of these semiconductors and how they impacted the performance of devices. Which is, you know-- again, was attractive to me because it was very practical. It had a practical end. And so that's when I decided, okay, this sounds like a good idea, and I want to get finished. Because I saw on the biophysics side, it was going to take me years for things to be done-- like angiography didn't happen until the mid-80s. And I was not that naive to say, “Okay, I want to finish and I like the spectroscopy and the photoemission. I like doing that. It has good applications.” And so that's when I said, “Okay, this is what I'm going to do.” And that was the rest of my thesis, was on three-five compounds and related things. And so, in a way it was maybe not so big-picture dreams, but it was fairly practical. It also fit in with the types of things that I liked to do. Which was, you know, the biophysics part was basically practical applications of science. And this was practical applications of science as well. Just in a different field.
Right. But the practicality, that's-- your interests there remained academic. I mean, you came at the practicality from an academic perspective, and not because necessarily you had an idea about starting a company or something like that?
No, it was academic.
Right, right. And to broaden that out a little more, what were those... Obviously, when you finish your dissertation, you're going to go on to different things, so what were those broader interests in the practicality?
So the broader interest was really to see, in the future, how could I apply this to devices? How could this knowledge help me learn more about how a device works? For instance, in those days, people were thinking of MOS-FETs for in gallium arsenide, and why won't they work? And it was because of the interface states, and we were learning the nature of the interface states.
And is there a way to probe those interface states? So, it wasn't like building the devices, but it was really understanding how to make something work. Which it really was the bottom line. And that expands to molecular beam epitaxy growing epitaxial layers. Not necessarily device layers, but layers where you can learn how the atoms go together. And that's really kind of the direction I came to it from.
I'm curious, what if any were some of the theoretical advances in the time that might have been useful or compelling to you?
So, people were just starting to do calculations of the band structures. And understanding what parts of the spectra contributed to the symmetry of the bonds. So you can start from calculations—Marvin Cohen at Berkeley was one of the people really pushing that. Where you could take his calculations and see on your spectra which was p-like, which was s-like. You could start to see, and then you could infer something about the surface states, which are the things that are doing the grabbing of the electrons. And you could look at angular studies, where you could see for instance, something had a particular symmetry, if you looked at particular angles, those symmetries went up and down in intensity.
And so, I think that's really where the theoretical side started. And then there were people calculating—at least trying to calculate—given a particular geometry, what kind of states would you be getting? And then could we see, basically, can we see those in our spectra? And that again goes back to surface states and interface states. And we were mainly, well, we were more in the interface state side. Because we wanted to look at when you put something on top of another, how does that screw up, or how does it help or hinder, the electronic structure? So, we studied things like Schottky barriers.
Who was on your thesis committee?
So, it was Doniach, Spicer, Lindau, and Clay Bates was the chair. He was a materials science professor. […] who had done x-ray photoemission. […]
[laugh] Piero, a more general question is, I like to ask about committee members because it gives an idea sort of the broader representation of the departments in SLAC who were relevant for your dissertation.
Yeah. And so, the people who were relevant were the three that I mentioned, and I would say Bienenstock was, you know, those were the four that were quite relevant for the research that I had done, I would say. And then there were a lot of, there were quite a few people who, I interacted with a lot of people just because of the nature of how the synchrotron lab is working. And so, people like Keith Hodgson was-- he had just started as an assistant professor in chemistry. He was a presence then and he continued throughout the time. And then I would say a lot of people who were influential were people who weren't necessarily at Stanford. I mean these were the people who came in to help us build the facility up, such as Dale Sayers from the University of Washington and Ferrell Lytle from Boeing, but this was essentially the Washington group. We worked pretty closely together, even though we may not have worked on the same experiments. And then people like Peter Eisenberger, and a group from China Lake... And so, I worked quite closely with all of them.
Yeah. Following your dissertation, what did you want to do next? What opportunities were available and most compelling to you?
So one opportunity would have been to stay.
At Stanford. And then--
If you did, you'd never leave.
Right. And so, I was thinking about leaving, and at that point I was really interested in in going out into industry. Because we had met some people at HP labs through the course of my graduate school. And so, I knew at least one person there, and I thought that work was interesting. I had friends at TI. And so, I ended up interviewing-- So you know, I told Ingolf and company, “Okay, it's time for me to find a job. So, if there's something here, let me know, otherwise I'm looking.” So Ingolf has always been very supportive and so he's never been one to say, “You should do this.” He's always been one to help you figure out what you should be doing, that you yourself figure out that you should be doing. He's been always very helpful in that.
And so, I started looking, and went and interviewed at HP labs. So, more electronics and devices. Varian. They had a job where they were going to try and make their surface science business more competitive. And then TI. A friend of mine talked me into going down there. He was from TI. Sandia. And IBM. And I interviewed at IBM because there were people coming from IBM, and Spicer said, “Well, why don't you do it?” And so, I basically did it. I wasn't particularly interested, but I kind of just did it to be nice and learn. You know, every time you interview, you learn something.
And so, Sandia was both Livermore and-- first it was Albuquerque and then Livermore, kind of both. So, I got offers from Sandia, Varian, HP, and TI. I didn't get an offer from IBM, because the guy asked me-- I just didn't fit in there, you know. The guy asked me, “What would you like to be doing five years from now?” And I said, “Well, not going to meetings all day.” That's—[both laugh] Anyway, so the two that I was most interested in were Varian and HP. And so Varian, I didn't quite trust them because I knew Ingolf had worked there as a postdoc, and they seemed to be a company that would cut projects off. And what they said to me was, “We want somebody to come in and take the surface science program forward-- You know, we'll give them free reign to do something with the surface science activity.” Because they had really nice hardware. But they were being killed competitively, I felt, by a company that is Physical Electronics, which is one of the major companies nowadays. And just because they know how to sell what people wanted, and they knew how to market it.
And so I decided-- And then there was one key person who moved from that group. And I realized from talking to Ingolf that right before they canned his project when he was there, the sane had moved from that project. So, I said, “You know, probably not a good idea.” And it turned out to be true. [laugh] That it was not a good idea. So, I went to HP. And I worked on laser annealing, which was new at the time.
Piero, I want to ask. Was there, by reputation and then from your own experience, how committed was HP to basic science? I mean, did it really model itself on the Bell Labs approach, or was there always an element of, “What you're doing really needs to be focused toward the corporate bottom line?”
Well, it was in between. It was applied science, and at the time in HP labs, people had their projects which needed to be focused on technology that could be applicable to future products. I think that's the best way to put it. And so, you know, there was research going on in developing new devices. There was research that was taking designs and building, let's say, LEDs and figuring out if they were going to work in the long term. Because the divisions had their own R&D that was more, I guess, more bottom-line related. It was not Bell Labs for sure, but it was one step removed from the divisions.
And what was your title? Like staff scientist, something like that?
I was a member of the technical staff.
Yeah. And what I worked on, you know-- I actually had quite a bit of freedom in figuring out what I needed to do. So, I had a goal, and I had quite a bit of freedom in terms of figuring out what I needed to do and how to do it.
Was the lab on the campus? The corporate headquarters campus?
Yeah, yeah. 1501 Page Mill Road. So, I primarily worked on gallium arsenide, but I also-- and I was working on ion implantation, laser annealing, and then I also worked with a group from HP Labs on Deer Creek Road which was the silicon part of HP labs, and one person was there who was trying to develop laser annealing for poly silicon. This was Ted Kamins. And so, he came down and basically he and I worked together on that and got a few papers out on silicon laser annealing. I think my major accomplishment was to show, I was supposed to be doing low resistance contacts using high dose implantation. So it was basically non-alloyed ohmic contacts for applications where you could have really planar structures and not heat things up during processing.
And I proved-- my contribution was I showed that it didn't work, and why it didn't work. [laugh] And that was probably three years, and then I started a new project on 1/f-noise. And that was in the fourth year that I was there, and I started getting antsy anyway. And so, I did some interviewing at Xerox PARC. They had a new laser project going on. And around that time, I got a call from Ingolf saying, “Yeah, check out this job opening that's back at the lab.” At SSRL. And so that got my attention. And so, I interviewed with that, and that's when I got the SSRL job, and then I stayed at HP for another few months finish out my projects.
Did SSRL-- I mean, how relevant was the offer to what you were doing at HP?
Well, by that time, I had decided that where my strengths were, were kind of figuring out-- Well, let me put it differently. I liked the idea of kind of being able to figure out what I wanted to do next. As opposed to have too much, too many constraints on what I wanted to do and what I could do next.
And so what I saw [in] the SSRL job, was the ability to basically do that and take what I learned at HP, which was really device technology, and apply it to more fundamental research.
So now I'd spent four years learning device technology. Now, coming back, I had something that I didn't have before I left, which before I had no idea about device technology. So now I could go back and take the device technology I learned, and apply the techniques that I knew from SSRL, from the synchrotron, to learning about device technology, how the device technology works. And then that actually has been a kind of the underlying thread of my surface science work. So, for instance, I've collaborated with chemists on campus, Chris Chidsey, is one notable one, where he's developing chemical treatments for surfaces. Well, I'm actually quite interested in understanding what those chemical treatments do. And so, we've had a number of students over the years that we co-advise where we applied the chemical treatments to these surfaces that he's doing, and then I'm able to do those chemical treatments at SSRL, stick them in the photoemission chamber, and see what the top monolayers are doing. And so we've had actually a number of students who have been doing that type of research.
For instance, Chris had developed a way of sticking organic molecules on a silicon surface. How do those organic molecules bond, where do they stick? What end is sticking? What's their orientation? How does that change as a function of the length of the organic molecule? And so for instance, we had a student who—this turned out to be my student—where we did that, and then we used photoemission techniques to study the bond between the silicon and the carbon in several related organic molecule. And then I actually did something called photoelectron diffraction, where we could look at the oscillations as you changed the energy to get an idea of the bond length and how it changed with the length of the molecule. So, there were quite a few things like that.
And then for instance, we also learned how you can etch silicon layer by layer in a chemical bath. So, this was all chemical baths as opposed to doing sputtering and the usual ultra-high vacuum techniques. And so, we applied that with a student that was working with Jim Plumber on campus. They were trying to do super high dose implants. And they weren't getting the right doping, and they were wondering, where did the doping go? And so, we applied our techniques, which is basically stripping the silicon layer by layer, and then using photoemission as a very surface-sensitive probe to be able to see what remains. When do you start seeing the doping? And when does it go away? And we figured out it was just on the oxide side of the interface. So that's the kind of thing. I would say the underlying interest that was driving what I was doing. Yeah, so I think that's sort of the gist of, I think, the answer to your question.
How much were administrative responsibilities baked into your initial role at SSRL? Were you able to really focus on the science on a daily basis?
Yeah, yeah. And so, focusing only on research didn't last that long, but I'm pretty good at compartmentalizing, and so I've been able to do both. I actually got into more administrative things in the mid- to late-80s, so I didn't have total free reign. But I'm able, like I said, able to compartmentalize well enough.
And was this initially a tenure track offer? Was it the equivalent to that?
No. During the time when I was hired, the departments really didn't have a lot of billets.
And so this position was (research) professor which was a five year term. And at the time, I really didn't care because coming back from industry, it was kind of like, you should change jobs every 4-5 years anyway.
In those days. I mean it was like pretty common. And so it really didn't bother me. At that time, I had colleagues, there were probably half a dozen of us, within EE who had the same title. And nominally, if you're on campus you have to raise your own salary in this position. Being at SLAC, my salary was covered by SSRL. So, I didn't have to do any of that. So, we actually used to meet and discuss how to best navigate this type of position. Two of us are still at Stanford, who were in this position. A number of the people have won a tenure line faculty job and got it at Stanford. Another person moved on to quite significant positions elsewhere. But so for me it didn't matter that much. The only thing that kind of was a little weird is that my home department was EE, because there was not a SLAC department. When SSRL became part of SLAC, my home department became Photon Science. […]
Yeah. So, I've been in that same position, however, when Gordon Brown was chair of the faculty, he basically talked handled my renewals and at one point, it just became more of a tenure type renewal. After that, it went from a five to seven-year term, to continuing. And that happened a while ago.
And as your administrative responsibilities and promotions grew over the years, did you become more involved with SLAC administration also? Or it was always focused on SSRL?
Well, I was focused on SSRL, but as time went on, I would get involved with SLAC administration as well.
I continued with my hands on research until probably ten years ago. When I became an acting director at SLAC of SSRL, probably around 2009, I had to let someone else take over running my experiments. I was in the acting director role for a year and a half. And at that time, I became involved much more heavily in SLAC administration. And then we hired Chi-Chang Kao as the SSRL director. He was in that position for two years during which time I was just starting to get my research back. And then he became SLAC director, and he asked me to be SSRL director, as the interim director. I have a hard time saying no, so I agreed.
And so at that point, it was just impossible to get my research back in the same way-- in a hands-on way. So that's where the staff that I was able to bring in continued the work on our microscope. I live vicariously through them. And it's basically looking at data and helping with analysis and figuring out what to do next. And that's actually not so bad. It's fewer hours spent in the lab struggling, but I still get the same pleasure out of the experiments.
Piero, you're very well-positioned to sort of talk broadly about how SSRL fits within SLAC overall. What is the overall relationship? In other words, why is SSRL within SLAC and not its own entity?
Ah. So, part of that is because of the DOE funding. It really has to do with the funding coming from DOE. When we were an independent laboratory, the way the bureaucracy worked, is that all of our money had to come through essentially an R&D proposal. Which had very little bearing as to what we actually did. For example, we got $400,000 to do research, and some millions of dollars to run a facility. When DOE reviewed us, they reviewed the millions of dollars based on the $400,000 of research that we did. It made no sense. So now we're part of the operating division of DOE, and they review us on what we should be reviewed on. And that's really what pushed us into being part of SLAC.
Originally, we were under NSF, and that made sense for being an independent laboratory. Unfortunately, NSF wanted to get out of the facilities business. Primarily because we were getting too big, and we were too big a draw on their budget. A similar thing happened with Cornell recently. So being part of SLAC, you actually have a much better way of getting money into the lab. Now, the other advantage is, for instance, when we started looking at next generation light sources. This was back in the 80s, we had workshops for next generation light sources. We weren't part of SLAC yet. And one of the things that came out of the workshop was what became the Advanced Photon Source. And DOE decided they were going to build the APS at Argonne and not at SLAC, probably for good reasons. A facility at Stanford would have been proposed by an entity that wasn't part of DOE.
Then kind of the next sets of workshops that were held in the late 1980s were going beyond the capabilities of the APS with fourth generation sources. That was a workshop that ended up pointing to the LCLS. And that's where the idea for the LCLS first came out, was from an SSRL workshop where we were looking at, well, what do we want to do next? And that turned into LCLS. But that became a SLAC project, and it was funded very generously by DOE. And so, I would say SSRL is actually this very small entity that started out as a sort of a parasite, generated the next, or part of, the next big thing from SLAC—at least for use of the LINAC. Which is LCLS, which actually has helped insure SLAC's future.
So obviously, administration and politics is a big part of SSRL and SLAC coming together. But I wonder in what ways there might be a mutually beneficial relationship, just on the science?
So nowadays, when you look at SLAC, you have to look at what is SLAC?
Right. Which really is a question that, you know, in 1963 in many ways sort of would have been much easier to answer.
Yeah. It was one thing.
So nowadays, when you look at what SLAC is and what it's trying to do, it is trying to build-- And I don't want to give short shrift to the particle physics side of the world, which is doing a lot of good things and is still there. Especially with the particle physics side of the world at SLAC partially reinventing itself on astronomy and looking up instead of looking in tunnels with accelerators. In technology, they're building detectors. I won't talk about that, but it's not because I don't think it's important, but because we’re focusing the discussion on the synchrotron side.
So, what is SLAC trying to do? Well, it's trying to build up a… Call it a materials chemistry activity. And that's been one of the major thrusts over the last few years. For example, when you look at Argonne, it is clear that they have very strong materials science, chemistry, biology programs that are bringing programs that are quite important. In addition, Argonne has battery programs and other things like that. SLAC has started small. Now, starting with the $400,000 that I talked about that SSRL was originally using to do materials science, and that was moved over to SIMES to create the SIMES laboratory at SLAC. And that activity has grown. And so if you look at that particular science, that is where SSRL makes a lot of contributions because the people who are growing materials and building materials use SSRL for characterization. And so, I think that's where if one were to say, okay, where does SSRL connect with SLAC on the science? You know, it doesn't connect on the 1963 science.
Maybe on the technology it does. Where do we connect nowadays? We also connect with the detectors.
That are being developed. The quantum information is another area where we connect nowadays. Because there's a lot of people on the solid state side who are studying quantum materials, and then there are people on the device side who are starting to try and build quantum information machines. And the solid state side may be a little far out, because they're studying charge density waves-- Maybe someday they will apply to devices that are put in quantum computers, who knows? That is where the connections are. And a lot of the fundamental understanding of these far-out materials are coming from SSRL.
Piero, it's a totally speculative question with obviously no correct answer, but I love to ask it because especially in light of you pointing out quite rightly, “What is SLAC now?” And so my question is, obviously you weren't around from the very beginning, but your institutional memory in connection is certainly there where, if Panofsky were around today to see what SLAC is, would it be recognizable? Not in the sense of the kind of science that it was doing, but was his vision, was it baked into his vision that SLAC by definition would be, you know, it would change with the times? That at a certain point, you know, if there was a roadblock that was come up against in linear colliders or high energy physics, that SLAC was more than just that one thing, and that it would change over time? Or do you not think so?
So, I think it was kind of interesting. That's an interesting question. The way he answered it when he was asked, people would ask him, “What do you anticipate in the lifetime of SLAC?” And he would answer, and I forgot the exact number, but he would say some number, say five, ten years, unless a new idea comes along. And so I think he was--
But I guess the question is, was the answer within the context of the next idea in linear colliders or high energy physics? Or he was really more expansive than that?
I think… He was basically thinking in terms of big questions. And materials science and stuff are often smaller questions.
I think he would be thinking in terms of cosmological questions-- You know--
But materials science is big insofar as SLAC has a big tent approach to science now.
Yeah, but I'm just thinking, what would Panofsky have thought? And I think he, I obviously can't speak for him, but my sense of him was that he wanted SLAC to be focused. His SLAC was one that was focused on a particular problem. You know, he did not see SLAC as a multipurpose laboratory.
Like a Berkeley.
Right. So, I think he still-- would he have been a fan of LCLS? I don't know. So that's a hard question to answer. But I think he probably would have been. I think he would be on the dark energy, dark matter side. I think of these big questions. Yeah, because on the materials science, chemistry side SLAC is answering big questions in these fields, but I don't think they're big enough. The individual problems wouldn't big enough for him.
But in terms of that overall, expansive institutional mission, how has SSRL contributed to those big questions, even if the material science itself is a smaller component to it?
The big questions in materials move pretty quickly, and right now batteries are a big deal, for instance. And that's one kind of a big question. SSRL with SLAC together are I think quite involved in answering those questions. The biology side, I think, is even clearer. The facilities that we've developed at SSRL and LCLS are answering some of the big biological questions. One prime example for SSRL is the discovery of the structure of RNA polymerase. There have been something like four Nobel Prizes that have come out of synchrotron radiation work in biology. And that all started with the work at SSRL, for instance, in proving that synchrotron protein crystallography actually will work and will contribute to the solving of structures.
Early on, when Keith Hodgson first came to Stanford, he's a crystallographer by training, and he was trying to develop the protein crystallography activity at SSRL. And it took quite a while for the protein crystallography community to accept the fact that they needed to go to a synchrotron. They wanted to do it in their own labs. And when they finally accepted that, I think it was a big revolution in how many structures they were able to solve and how many problems they were able to deal with. So, from that point of view, that is a big science area with big questions--
It's not only big science, but it's basic research that very concretely has societal implications.
Right. Right. Exactly. And most recently, we've established some cryo electron microscopy facilities. And that happened because, I think Keith was involved with that with campus people. He lined up with a few Nobel Prize winners and they got money out of Stanford to start buying the hardware, and SLAC agreed to install it at SLAC. And that's equally important now, because the way things are going, that goes hand in hand with the protein crystallography. From a different direction, but it's making big societal impacts. Now would Pief, for instance, have agreed that it was a good idea for SLAC? I’m sure he would have thought this was a good idea but not for the SLAC of his time when large accelerators were still being built at SLAC.
He might have tolerated it, but he wouldn't have seen that as a big direction for SLAC. But who knows?
Let's go right to the present in terms of your position as chair of the photon science group at SLAC.
I just finished my term.
Oh. Well, congratulations are in order. [laugh]
Yep, yep. I ended my term this year. This summer.
In what ways was that a sort of natural progression from SSRL and in what ways was that a real career change?
Oh, I mean I didn't change my activity at SSRL.
Oh, you didn't?
No, no. I was still deputy director and doing what I... So--
So, you just simply added this to your portfolio?
And because this is very different from a campus chair.
I mean, campus chairs continue to do research and they continue to teach. And so, I continued to teach, I continued to do research in the way that I was doing it. But this was a, in my view-- it was basically a service to the lab. It wasn't a career change. I was able to, in a way, provide input. This is one way where you can actually get more involved or continue to be involved in the SLAC administrative areas. Because it allows me to continue to give input to the lab director, who's also effectively the dean of the SLAC faculty. And the big difference from campus is that I didn't have to deal with space or the money needed to run a department. All that stuff is done overall by the line management structure.
What I needed to deal with was trying to create new faculty positions and get approval from the lab director. We were able to do a few of those. Then trying to put forward a vision for the future of where the faculty could be going. And that's an ongoing discussion. And the new people who have come in, Kelly Gaffney is the one who took my role, and Phil Schuster on the PPA side is the other. And that's something they're continuing on because it lays out what will happen in the future with respect to new areas of emphasis. A lot of the faculty are joint with campus, but quite a few of the people are only at SLAC. Campus doesn't fund faculty here. It's not part of the endowment. And so, whoever SLAC hires as faculty, has to be supported somehow. And questions come up, for example, since we're trying to empower staff to be PIs, which has been done. Then what's the difference between faculty and staff, if you're bringing in high level staff, you can't make everybody faculty. Because you don't have the billets, even though you might have the money. So that's adds complexity. This is one of the things that SLAC is trying to kind of work out. Before, in the old SLAC, it was very cut-and-dry because the faculty were the line management.
Nowadays, both faculty and staff can be part of upper management. In the “old days”, primarily faculty were in the upper management. […]
Another sort of broad-based structural question. Over the years, how has SLAC's relationship with the DOE changed?
I would say it's gotten broader. Before, high energy physics was the primary funding source. When SSRL’s funding was moved from NSF to DOE, it had a relationship with the materials and chemistry divisions. When SSRL became part of SLAC, we had a relationship with the operations division of DOE. What's now called the energy sciences directorate has created more connections to materials and chemistry. SSRL has a strong relationship also with the office of biological and environmental research. Not only basic energy sciences. So we have those two connections.
After Persis Drell and then Chi-Chang Kao came in as directors, the connection to basic energy sciences has gotten stronger. I don't know-- I think connection to high energy physics has always been good, but that I'm not that familiar with it. So SLAC is working at becoming more corporate in the sense of tapping into different offices of DOE including fusion energy sciences. And of course, you have other labs like Argonne who've been around for a lot longer, and they've always had those connections because they have a broader base. They were designed, LBL as well, they were designed to be multi-purpose laboratories. So they had in-roads into more offices at the DOE.
So just to bring the narrative right up to the present, since you stepped down just recently, what are you doing now?
Okay so when I stepped down from faculty chair, Chi-Chang asked me to chair the laboratory promotions committee for staff scientific and engineering staff. So I do that. And then he asked me if I would be deputy chief research officer. So, this is working with JoAnne Hewett who is the CRO. And those two functions are very closely related. Because a lot of it has to do with staff promotions, staff status, PI status for staff, it's a lot of administrative details. And so that's something that I've just added to my list of things to do. And it's stuff that's pretty straightforward to do. It's essentially a 20% job. It sometimes takes full time for a short amount of time. But most of the things I do relate to SSRL and then talking to people. So, I provide advice to people, to staff scientists and other. And so, I probably spend much of my week talking, meeting with some staff scientists who I collaborate with, some who just need advice or suggestions for navigating various things.
And this is a, as opposed to the laboratory work, this is a remote-friendly kind of responsibility now? You can do this from home?
Yeah, yeah. Yeah. And you know, it's actually pretty good given the pandemic. I mean-- [both laugh]
It's one of the few benefits of administrative responsibilities right now, I suppose.
Yeah, yeah. Yeah.
Well, Piero for the last part of our talk, I want to ask one sort of broadly retrospective question about your career, and then one looking forward. So going all the way back to when you were figuring out, you know, going from biophysics to surface science and then how your career really took off from there. On the research side of things, because obviously that's much more interesting than the administrative side of things, on the research side of things, given how broad your interests have been over the years, what's the sort of overall interest or narrative through-line that sort of connects all of your work on an intellectual level, would you say?
Yeah. So, I would say looking for problems that have a practical application where the work that I'm doing on the synchrotron can be applied.
Yeah, and so that's been pretty consistent. I've already, I've told you about the surface science part.
And I also look for, on the synchrotron side, I look for opportunities where I can make SSRL a useful tool for these studies. In a way, that's more altruistic, but it's part of it. It's a strong part of it. For example, I also worked in areas beyond the surface science, although that thread has continued at different levels depending on what else I was doing. Through the 1980s, I was doing primarily surface science, photoemission, on various materials I described above. In the early 90s, I had discussions with people that I knew from Intel who were interested in looking at trace contamination on silicon wafer surfaces. So, it was still surfaces. Very important because they were trying to develop the technology for higher density chips and the contaminants were screwing up the gates. And then we had a very similar discussion with some people I knew from HP.
So the three of us connected, and I basically developed apparatus at SSRL with a few of the staff scientists. We developed this together where we could do extremely sensitive measurements of contamination. That ended up bringing together about 20 companies. The technique is called Total Reflection X-ray Fluorescence, or TXRF. We then connected our work with Sematech which was a non-profit consortium of semiconductor companies to advance chip manufacturing. We brought the 20 companies together under the Sematech umbrella. This program continued for about ten years with various companies, such as, Bell Labs, AMD, Intel, HP—you name it, they were part of it. This also included Rigaku, which is an x-ray company in Japan that makes x-ray instrumentation including TXRF. Some of the wafer manufacturers from the U.S. and Japan were developing chemistry to clean the surfaces.
The companies would work on new cleaning chemistries, and we would then essentially have a very intensive feedback loop where we would evaluate the cleaning processes. This project went a little bit beyond the time the dot com bubble burst. When that happened, the industry direction changed and many of the participants got laid off. We continued doing research for a couple of years and then moved to something else. But that's the same thread. It's applying a synchrotron technique to a practical problem. And in this case, the problem had industrial significance. We were able to make an impact when companies were developing new chemical cleaning techniques and learning how to make better chemicals. We had to do the characterization because they couldn't measure it elsewhere and we were able to give them the answers they needed.
By the end of the 90s, they'd figured out how to do get very clean surfaces. Rigaku was developing an instrument that could be deployed in a semiconductor fab. To make this instrument work, they needed ultraclean chemicals to etch and concentrate the contaminants to be in the sensitivity range of their instrument. Our measurements on their wafers enabled them to fine tune their chemistry. Fortunately, by 2000 we essentially met the goals we collectively set, and measurements moved into the semiconductor fabs. By 2003, the SPEAR accelerator was completely rebuilt and into a high brightness source now called SPEAR3. We were only down for about nine months. We then basically said to our TXRF collaborators, “Okay, we have to rebuild the beam line, so if you guys want to continue this program, we have to put in some money to rebuild the beam line.” We had a company who was interested in helping us develop the funding, but when the dot com bubble burst, a number of people got laid off and the program went away.
Well, we rebuilt SPEAR and so we looked for new things to do that would be applicable to interesting research? We built another totally different apparatus to do microscopy, or fine focus imaging. We worked on some of the NASA missions. Stardust for one, and we were able to make contributions there. In the meantime, I was looking at a longer-term project, which ended up being an x-ray microscope that could do full field imaging at 30 nm resolution over a 30-micrometer field of view. This is a transmission x-ray microscope or TXM. I connected with a local company, X-Radia, and we developed with them instrument serial number #3, which brough me back to my biophysics interests. I was able to get a project funded by NIH to study the nanostructure of bone.
We spent the next five years working with biologists to look at the effects of simulated weightlessness and the effects of drug treatments on osteoporosis. We've continued the x-ray microscopy program after the NIH work ended. We continued that project from about 2005 through today. After the NIH project we've done chip imaging with USC related to a DARPA project which greatly improved our instrument. For the last ten years, we've been doing materials science. Batteries, catalysis, chemistry, materials science. And that's one of my continuing programs.
But again, it all has the same thrust. Which is the overlying theme that I mentioned above, which causes me to change research directions, which is fine because it keeps me more interested in doing the development of the new tool that will address a new problem, versus necessarily studying a particular problem to death. We still use the techniques we’ve developed on new problems. For example, we used TXRF when we worked with Applied Materials to understand how high dose doping changes when the wafers are annealed using new rapid anneal methods. Annealing of dopants actually went back to what I worked on when I was at HP.
So, what I've found over the years, is that every five years, somebody comes up with a new way to anneal semiconductors after they’ve been dope. And I often find myself working with people who are doing those things to figure out where the atoms are. And so in our latest study with Applied Materials they had a new plasma emersion method but they weren't getting the doping density that they were expecting. Which is what was happening to me at HP back in the 1980s. And so, we worked with them with better spectroscopy techniques to figure out where the atoms were going and how they were consolidating with defects. This information doesn't help them in terms of how they fix the problem, because they find fixes to work around the problems. But what it does allow them tell their customers “this is what's happening,” which may lead to a fix. But again, this is the same thread going through my research. Now, what am I going to do next? I don't know.
Well, that actually gets me to my last question. So looking ahead, I mean my first question there is—in the world of lab work and experimentation—how do you stay fresh where remote work is very much our new normal for the ongoing future, for the foreseeable future? And more broadly from that, in what ways is SLAC needing to really change with the times because we seem to be in this for a while now?
Yeah. So for myself, it's really focusing on fewer things. So, I still had a photoemission chamber sitting on a beam line that we closed to users because we didn't have enough staff to run it. And every once in a while, somebody would come along who wanted to do something. And I would say, “Okay, let's go do it,” and we'd just go do it. It was quite a bit of fun as well as being useful. So, I kept that chamber alive because I had a dream of getting out of a lot of the administrative things and spending time in the lab. My plan was to get it to a point where it was self-sustaining and self-running. With COVID and all everything else going on, I basically gave up on that. I mean it's just not going to happen. And so let's use the space for something else, you know? I've told the guys, “Go clean out the cabinets, do what you need to do, and use the space.”
So, I have to do fewer things and so my focus on the research side will be on the x-ray microscopy. We have staff people who are actively working on the program, and we work together. On that project we are looking to improve the instrument, how do we do different modalities for the microscopy, and so that's basically discussing. We want to do phase contrast with this microscope that's better than how we were doing it before. What kind of optical elements can we put in? How can we improve the microscope? I used to be able to just go do it.
Now, if I go to work in the lab, I need to spend a little time to get my sea legs back. You go into the lab after you've not been there for a little while, you break things. And so with COVID, I'm not going to be able to routinely go into the lab. Because if I go in, somebody else can't. And from a career perspective, you know, I'm way past retirement age. And it's their turn to be able to do the good experiments. Even if I can’t go into the lab easily, work through my collaborators. So, if I can supply good ideas and I can listen to their ideas, and give good feedback, then that actually is a plus for me.
I also have a few people who report to me, but that I don’t collaborate with scientifically. One of the people is working on an accelerator physics problem that's a materials science application to accelerator physics. I'm not involved in the research, but I'm involved in providing advice on the research. So, I don't get my name on the papers, but I get-- what do I call it? Satisfaction in seeing the person doing good work developing new things. Whether I get credit or not, at this point it doesn't matter. I get credited in different ways. But you know, this is really neat, and this person has gotten an early career award to build on this work. It's very, very neat. The work involves hitting a surface with radio frequency waves and then watching the surface react using x-rays as a probe. Very neat stuff.
Another person who reports to me is developing novel x-ray optics as well as building a nano fabrication facility at SLAC for making these optics. Since I understand what she's doing, and so, even though I'm not part of the research, I'm able to provide advice and counsel as to how to get things done. And then there are the microscopy people. I am involved in the research, and we talk a lot. Then there are other people who are doing materials science work that involves machine learning. I don't do machine learning, but I can give advice on how to structure experiments. And again, I don't get my name on papers, but I draw satisfaction from seeing the work happening.
Well, it certainly sounds like you have very well-thought-out ideas about how to keep things interesting and being engaged no matter where we're headed in the future.
Yeah. Right, right, and the other thing I enjoy is the engineering side, where I interact with the engineers and physicists who are building beam lines. This involves looking forward to improve SSRL capabilities. How to best implement some ideas for a beam line. That is also fun for me, because I can kind of listen and say, “Well why don't you try this?” We're also trying to develop a new beam line in the so-called “intermediate” energy range, which is from about 5 kilovolts down to about 500 eV. This is something I’ve been interested in for quite a while. I think I've gotten some traction on that. And so […] we’re looking into a bean line for materials science and growth with a lab built around it. This may lead to a new concept of how to do synchrotrons in the future, which connects to kind of a very long-term plan of building a new SSRL with a of state-of-the-art SSRL facility. So that's where I see my longer-term contributions.
Well, Piero, it's been absolutely fascinating hearing all of your perspectives on things throughout your career, so-- I know the SLAC folks are going to be quite interested in this interview, so I really appreciate you spending this time with me today.
Well, my pleasure. It's been good talking to you.