Lee Pondrom
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ORAL HISTORIES
Credit: Lee Pondrom
Interviewed by
David Zierler
Interview date
Location
Video conference
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Interview of Lee Pondrom by David Zierler on May 11, 2020,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
www.aip.org/history-programs/niels-bohr-library/oral-histories/46754
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Abstract
In this interview, Lee Pondrom, Professor of Physics Emeritus at the University of Wisconsin, Madison, recounts his childhood in Dallas, San Antonio and Houston and describes his early interest in science. He explains his motivations to attend Southern Methodist University, where he pursued a degree in physics. Pondrom discusses his graduate work at the University of Chicago where the long-range influence of the Manhattan Project remained strong, even in the early and mid-1950s. He describes his summer research work at Los Alamos, and his thesis research on cyclotrons and pi mesons under the direction of Albert Crewe and Uli Kruse. Pondrom conveys the feeling of excitement at the discovery of parity violation while he was a graduate student, his postdoctoral work on the Nevis cyclotron while at Columbia, and he describes his Air Force service after he defended his dissertation. He describes the opportunities leading to his tenure at the University of Wisconsin and a research agenda that included long-term projects at the Chicago cyclotron, and at Fermilab and at Argonne. Pondrom discusses his contributions to CP violation, hyperon decay and how computers have been useful over the course of the career. He describes the origins of Fermilab and his experiences at Madison during the student unrest during the late 1960s, where bombers targeted science buildings. Pondrom discusses the significance of the E8 experiment as an extension of the Garwin-Lederman experiment and the origins of the Tevatron project. He explains the ups and downs of U.S. high energy physics during the SSC years and he surmises what would be known now in particle physics had the SSC been completed. At the end of the interview, Pondrom describes his extensive collaborations in Russia and his study of Soviet-era physics, including his work on Stalin’s nuclear diplomacy.
Transcript
Zierler:
This is David Zierler, oral historian for the American Institute of Physics. It is May 11th, 2020. It’s my great pleasure to be here with Professor Lee Pondrom. Lee, thank you so much for being with me today.
Pondrom:
My pleasure.
Zierler:
OK. So to start, please tell me your title and institutional affiliation.
Pondrom:
Professor of Physics Emeritus at the University of Wisconsin, Madison.
Zierler:
OK. And now, let’s go right back to the beginning. Tell me a little bit about your birthplace and your family background.
Pondrom:
OK. I was born in Dallas, Texas, December 1933. My family were native Texans. My father was a banker. I grew up in Dallas and San Antonio and Houston during the war and graduated from Highland Park High School in Dallas in 1950.
Zierler:
Now, why did you move around during the war?
Pondrom:
Well, my father was not in the army, he was in the army in World War I, but he was an executive at the Federal Reserve Bank, and it had branches in San Antonio and Houston. And so, from Dallas, which was the main bank, he moved to San Antonio and to Houston to run those two branches during the war. And we returned to Dallas, I think, in 1946.
Zierler:
Now, did you go to public schools in Texas throughout your childhood?
Pondrom:
Yes. Highland Park High School is a public school.
Zierler:
Now, at what point did you start to develop an interest in science?
Pondrom:
Well, I’ve always been mechanically inclined, and I built electric trains, so I knew how to wire things up. And I made model airplanes with gasoline engines and I flew them around. And then, when I was in high school, I made a six-inch, f/8 reflecting telescope. I ground the mirror in the garage and did all the optical tests on it and set it up in the backyard in Dallas and started looking at the moon and the planets and various things.
But I got bored quickly with sitting outside in the cold weather [laugh], although making the telescope was fun. So then, when I went to Southern Methodist in college, the first thing I did was take calculus, and then I was a physics major and I got interested in atomic physics and quantum mechanics.
Zierler:
Now back in high school, were you a standout student in science?
Pondrom:
Not particularly, no. Highland Park High School is a very good school, and I was sort of in the top third of my class, but by no means one of the leaders.
Zierler:
Now, why did you chose Southern Methodist?
Pondrom:
Well, of course, it’s in town. I was only 16 when I graduated from high school.
Zierler:
Now, did you skip grades?
Pondrom:
Yes, I did skip grades when we moved around during the war. I went from one school to another, and I think it was in San Antonio that they decided that I knew too much to be in the 5th grade so they put me in the 6th grade, something like that.
Zierler:
Uh-huh.
Pondrom:
So, when I got back to Dallas, I was a year younger than everybody in my class. The class that I started out with was one year behind me. So, I think my family felt that it would be better if I lived at home to go to college.
Zierler:
Mm-hmm.
Pondrom:
And Southern Methodist is really within walking distance of where my house was, so—
Zierler:
Now, at what point did you declare the major in physics as an undergraduate?
Pondrom:
Pretty much right away. Yeah, pretty much right away.
Zierler:
Now, were there a lot of veterans who were older at SMU at that time from coming back from the war?
Pondrom:
They had pretty much gone. Now, this was 1953, so the World War II veterans were pretty much gone by then.
Zierler:
Mm-hmm. And, early on, what caused you to focus on physics? What was it about physics that you wanted to study?
Pondrom:
Well, that’s a good question. Again, I think it’s my mechanical ability and the fact that I like to build things and I like to know how things work.
Zierler:
Although that sounds a little more like engineering in some ways, right?
Pondrom:
[laugh] Well, experimental physics, a lot of it is like engineering.
Zierler:
Right, right.
Pondrom:
So, yeah. I thought that the challenge of the field was interesting, that would be something that would keep me interested, and it has.
Zierler:
Now, did SMU emphasize the experimental courses over the theoretical courses in the undergraduate program?
Pondrom:
Southern Methodist had a small physics department. There were only three faculty members at the time.
Zierler:
Mm-hmm.
Pondrom:
Now it’s bigger. The temporary existence of the supercollider had a big effect on physics departments in the Dallas area.
Zierler:
Right.
Pondrom:
And Southern Methodist now has quite a respectable physics department, but, in my day, there were only three faculty members. One of them was an expert in acoustics, and one was educated at the University of Chicago, which is where I went to graduate school.
Zierler:
Is that the connection?
Pondrom:
Partly. Another connection is a lifelong friend, Jim Cronin—
Zierler:
Oh, yeah.
Pondrom:
—who was two years ahead of me in high school, but he was also a Highland Park High School graduate. His father was on the faculty at Southern Methodist. He was in the Greek and Latin department. And Jim was a physics major at SMU, and then went to the University of Chicago to graduate school, so he was one of the reasons why I went to Chicago.
Zierler:
And you stayed in touch with him as an undergraduate?
Pondrom:
Yes, yes.
Zierler:
Now, at what point did you determine that you wanted to go right on to graduate school? I mean, particularly with your talent in building things, did you ever consider entering industry after SMU?
Pondrom:
Well, yes, I did. Texas Instruments was in Dallas and was sort of a fledgling company in those days.
Zierler:
Right.
Pondrom:
And they did try to hire me, and I decided that I really preferred to go on to graduate school.
Zierler:
Now, was your sense with Texas Instruments, were they trying to build a basic research program like a Bell Labs or a Westinghouse?
Pondrom:
Yes, yes, mm-hmm.
Zierler:
But you wanted to go on to graduate school?
Pondrom:
I wanted to go on to graduate school.
Zierler:
So, when you got to Chicago, this would have been, what, the fall of ‘53?
Pondrom:
Correct.
Zierler:
What were your impressions of the department? What was going on at Chicago physics?
Pondrom:
Oh, wow! Well, it was one of the best physics departments in the world.
Zierler:
And did that fact—was that apparent to you at the time?
Pondrom:
Sure was. [laugh]
Zierler:
Describe the scene to me.
Pondrom:
Well, it was amazing. You know, all of these people from Los Alamos—first, the Chicago laboratory, the so-called Metallurgical Laboratory—
Zierler:
Right.
Pondrom:
—was a big part of the Manhattan Project. By the time I had gotten there, why, Arthur Compton was no longer in the department, but he was the one who headed the Metallurgical Laboratory, which was a branch of the Manhattan Project. And Fermi built his first reactor across the street from the Research Institutes at the university.
Zierler:
Yeah.
Pondrom:
And Fermi was still there when I came.
Zierler:
Did you have interaction with him at all?
Pondrom:
I listened to his quantum mechanics class which exists in published form as his handwritten notes. He wrote out these handwritten notes and passed them to the class. But this was my first year in graduate school and I didn’t really follow him. He was too slick.
Zierler:
Now, coming from the small program at SMU to a world-class department like Chicago, I wonder, how well prepared did you feel that you were when you started out, or did you have a lot of catching up to do?
Pondrom:
Well, it’s hard to say. I certainly felt like I had to work.
Zierler:
[laugh]
Pondrom:
But I managed, OK. I was a successful graduate student.
Zierler:
And when you got there, were you already set on experimental physics? Was that your game plan going in?
Pondrom:
I think so. Of course you take mostly theory courses. You take quantum mechanics and you take classical mechanics. There were lab courses at Chicago, and I took some lab courses. And then, in the summer of ‘55, I believe it was, I was a summer student at Los Alamos, and I did experimental work at Los Alamos.
Zierler:
Now, how did that come together? What was your connection to Los Alamos?
Pondrom:
I must’ve applied for a summer fellowship from the University of Chicago.
Zierler:
I’m sure there were very strong institutional connections between Chicago and Los Alamos?
Pondrom:
Yeah. And I don’t remember who actually did it as a faculty member at Chicago, who helped me get an appointment at Los Alamos, but I was out there for three months.
Zierler:
This was your summer between your first and second years?
Pondrom:
Second and third.
Zierler:
OK. And what was the project you were working on at Los Alamos?
Pondrom:
It was an experimental project on firing circuits for conventional explosives.
Zierler:
Was that a fun experience?
Pondrom:
Yeah. It was a very interesting experience, yes.
Zierler:
Did you have to get a clearance to do that work?
Pondrom:
Oh, yes, yes. And I had fingerprints taken at the Hyde Park Police Station—
Zierler:
[laugh]
Pondrom:
—near the University of Chicago.
Zierler:
Yeah, yeah.
Pondrom:
Happily, it was the only time I was in the Hyde Park Police Station. [laugh]
Zierler:
Good! [laugh]
Pondrom:
That’s the good news.
Zierler:
Right, right. Now, did your experience at Los Alamos, did that help shape your career path, the kinds of things you wanted to work on?
Pondrom:
I think so. I mean, they encouraged me while I was out there to stay within experimental physics, and I hadn’t really picked a thesis topic or a sponsor at that time.
Zierler:
Mm-hmm. And then, so what was your process for developing your dissertation topic?
Pondrom:
Well, let’s see. Again, Jim Cronin played a role. His thesis work was in nuclear physics. He worked in Sam Allison’s lab, and I helped him as a sort of a lab technician making thin targets and things like that for the Van de Graaff. So, I decided, after taking the basic examination, to switch to the cyclotron instead of staying working on the Van de Graaff.
Zierler:
How come? What was it about the cyclotron?
Pondrom:
It just seemed more exciting, actually.
Zierler:
Yeah.
Pondrom:
And there were two young professors who were working on the cyclotron at that time.
Zierler:
How new was the cyclotron when you got involved?
Pondrom:
Well, let’s see. I think it started working around 1949 or something like that.
Zierler:
OK.
Pondrom:
So, it had been running for five or six years.
Zierler:
And what was your sense of some of the broader research questions that the cyclotron was positioned to help answer?
Pondrom:
Well, people were studying pi mesons. The switch had already taken place from cosmic rays. Initially, many of the discoveries in elementary particle physics were made using cosmic rays as the accelerator. That’s where the pion and the muon were initially discovered. And the strange particles were discovered in cosmic rays. But once they started making these high-energy accelerators, people who wanted to study the new particles switched away from cosmic rays to the accelerators as a better source for the particles. And the cosmic ray physics kind of became a backwater, at that point, where it stayed for many years. It no longer is, but—
Zierler:
Yeah. When did it come back? What was your sense of when it came back?
Pondrom:
Oh, it came back in the ‘90s. I think that is probably a fair estimate of when it started to come back. When people started constructing these really large detectors, and of course, the space program, which is a completely different story, also played a role in the interest in cosmic rays becoming more central.
Zierler:
Mm-hmm. Now, who was your advisor?
Pondrom:
I had two advisors, Albert Crewe and Uli Kruse. And Albert Crewe was British. He had just come from England to Chicago to do some technical work on the Chicago cyclotron. And so I started working with those two guys. And, in those days, why, you spent a lot of time doing heavy work. And we used to move magnets around and do bragging of—
Zierler:
Now, when you say “heavy work,” you literally mean heavy work; you’re pushing stuff around the lab?
Pondrom:
I literally mean heavy work, yes. [laugh]
Zierler:
[laugh]
Pondrom:
Yes, yes. Yeah, and we did a lot of stuff that they wouldn’t let you do anymore.
Zierler:
Right, right. Now, your dissertation topic, was the research question essentially handed to you from your advisors or did you mostly come up with it yourself?
Pondrom:
I think it was a little bit of both. But it was a pion production experiment, strong interactions.
Zierler:
When did you—as a dissertation student, obviously, you’re narrowly focused, right? You’re working on trying to get it done. But I wonder if you ever thought about how your work sort of fit in with the broader field, what impact you thought your dissertation might make?
Pondrom:
To change the subject slightly—
Zierler:
[laugh]
Pondrom:
—while I was working on this, the parity violation was discovered. So that was going on at the cyclotron, and at the cyclotron at Columbia. At these two places people were studying weak interactions. And I was not participating in that, but I certainly followed it very closely.
Zierler:
Now, why were you following it? Was it relevant specifically to your research?
Pondrom:
Well, it was really interesting.
Zierler:
Uh-huh.
Pondrom:
I mean, it was really interesting.
Zierler:
And what was interesting about parity violation?
Pondrom:
Well, it’s just a fascinating phenomenon, and it still is. And I think the most interesting thing, and something that I capitalized on later in my career, is that the precession of the magnetic moments of elementary particles can be observed by the parity violating distribution of particles in the final state, the daughters from the decay of these particles. And the original muon experiment that was done by Garwin and Lederman was the precession of muons in a solenoidal magnet with coils wrapped around a coffee can [laugh]—
Zierler:
[laugh]
Pondrom:
—in a beam at the Columbia cyclotron at Nevis. And that changed the world.
Zierler:
Right.
Pondrom:
So this was really interesting stuff. At Chicago, the professor who was doing this was Valentine Telegdi.
Zierler:
Yeah.
Pondrom:
And I was certainly—I was not in Val’s group, but I knew people who were, and I was very friendly with Val, and stayed that way for the rest of my life.
Zierler:
Now, when you say that parity violation changed the world, is your sense that—did it upend previously held theories or concepts in physics, or was it more about filling in gaps in knowledge?
Pondrom:
No. It upended concepts in physics.
Zierler:
Such as what?
Pondrom:
Such as parity conservation. [laugh]
Zierler:
[laugh] Well put.
Pondrom:
I remember a quantum mechanics class with Gregor Wentzel in which this possibility of parity violation was brought up by somebody in the class, maybe even me.
Zierler:
Yeah.
Pondrom:
And Wentzel said, “That’s just inconceivable.” You know, forget it. It won’t happen.
Zierler:
Right, right. Famous last words.
Pondrom:
Famous last words. [laugh]
Zierler:
Now, was this research—did this directly impact your own dissertation, or you felt like this was a separate field of study?
Pondrom:
No. No, it didn’t.
Zierler:
Uh-huh. And who else was on your thesis committee?
Pondrom:
Oh, Wentzel was, and Kruse and Crewe, and there must’ve been another couple of people, but I don’t remember their names.
Zierler:
Yeah, yeah. And so you defended—this would’ve been, what, the fall of 1958?
Pondrom:
Spring of ‘58.
Zierler:
Spring of ‘58.
Pondrom:
Right.
Zierler:
And then you entered the Air Force?
Pondrom:
That’s correct.
Zierler:
How did that come about? Were you drafted?
Pondrom:
I was a ROTC student at Southern Methodist.
Zierler:
Oh.
Pondrom:
I was commissioned a lieutenant in the Air Force, and they deferred me to go to graduate school.
Zierler:
Did you keep up any relations with the Air Force?
Pondrom:
I didn’t, no. I didn’t do any guard work or anything while I was in graduate school. It was when I graduated there was an Air Force major who visited me at the Research Institutes at the University of Chicago and welcomed me into the Air Force.
Zierler:
[laugh] Were you surprised to receive the call or you knew this was coming?
Pondrom:
I knew it was coming.
Zierler:
Uh-huh. And did you have any misgivings about the service, that this might interrupt your career trajectory?
Pondrom:
Yes, initially, but it wasn’t a big deal. The Air Force was fine. I got along.
Zierler:
Yeah. Were there any opportunities to put your expertise in physics to the service of the national defense?
Pondrom:
Yes. I was somewhat unusual, having a PhD in physics from the University of Chicago—
Zierler:
Right. [laugh]
Pondrom:
—and being a first lieutenant in the Air Force. So, I kind of stood out.
Zierler:
Where were you stationed?
Pondrom:
I started out in Washington in the Pentagon and in the Air Force Office of Scientific Research.
Zierler:
Oh.
Pondrom:
And I was on a bunch of committees in the Pentagon, way over my head, but—
Zierler:
[laugh]
Pondrom:
—so what. Then, after six months, I was transferred to Wright Field in Dayton, Ohio where they had a Van de Graaff for nuclear physics studies. They had installed this Van de Graaff when they were trying to make designs for a nuclear-powered airplane. But they decided that the lead shielding was a little bit too heavy to fly, so they gave up on that.
Zierler:
[laugh]
Pondrom:
But they still had the Van de Graaff, so they shipped me out there to do something with it, and I did.
Zierler:
What’d you do?
Pondrom:
Well, I did some experiments with deuterons, and it was nuclear physics, and I published the papers, and so it was a very successful interlude, you might say.
Zierler:
Now, was this, as far as you knew, the beginning and the end of the concept of nuclear-powered aircraft?
Pondrom:
Oh, it had already ended by the time I got there.
Zierler:
[laugh] OK.
Pondrom:
Yeah. [laugh]
Zierler:
Did you ever give any thought to being a career military man or you—
Pondrom:
I did.
Zierler:
Yeah?
Pondrom:
I did, I did. I thought, well, if I stayed in, I might make flag rank if I played my cards right.
Zierler:
Yeah.
Pondrom:
And that might not be so bad, because the Air Force was not an unpleasant experience.
Zierler:
Sure. And you were also there during peacetime?
Pondrom:
And I was also there during peacetime, although, when I was an air cadet from Southern Methodist, this was in—what?—must have been 1952 during the Korean War, I was at Luke Air Force Base in Phoenix, Arizona for a summer study. And that was real Air Force. They were training pilots for the Korean War.
Zierler:
Yeah, yeah. I wonder if you ever gave any thought that, had you stayed in, you would’ve found yourself over Vietnam in a matter of years?
Zierler:
OK. So let’s go back to—you cut out for a second there. The last I heard was, when I asked you if you ever gave thought about had you stayed in, you would’ve found yourself over Vietnam. The last thing I heard was you said, “It’s possible.” I didn’t hear anything after that.
Pondrom:
OK. Well, the Vietnam situation is in the ‘60s, and there were several international crises before Vietnam became a big deal.
Zierler:
Right.
Pondrom:
And one of them was the Cuban Missile Crisis.
Zierler:
Absolutely.
Pondrom:
Another one was the problems in Berlin. So this was when I—I was still in the Air Force reserve when I was at Columbia. And I got discharged in the early 1960s.
Zierler:
Now, how did the opportunity at Columbia come about? Was that a postdoc?
Pondrom:
That preceded the Air Force.
Zierler:
OK.
Pondrom:
I had a job at Columbia after I graduated from Chicago.
Zierler:
Now, that initial job—
Pondrom:
And they just held it.
Zierler:
—was that a postdoc or was that a tenure-line position?
Pondrom:
Well, I was an instructor.
Zierler:
OK.
Pondrom:
[laugh] Which just meant I taught, but it wasn’t really a tenure-line position. It was faculty.
Zierler:
Yeah.
Pondrom:
Assistant professor is higher ranking, though.
Zierler:
Right, right. Were you able to continue your research at Columbia or you were mostly just teaching?
Pondrom:
Yes, yes, Yes, yes.
Zierler:
And so what were your research projects during the Columbia years?
Pondrom:
Well, I worked at the cyclotron at Nevis, and I—
Zierler:
Where was Nevis?
Pondrom:
It’s up the Hudson River. It’s in Westchester County.
Zierler:
OK.
Pondrom:
It’s about a half an hour from Manhattan.
Zierler:
And what were some of the projects that were going on there during your time?
Pondrom:
Oh, wow! Well, Lederman and Schwartz and Steinberger were all three there. And they were building equipment for the neutrino experiment which was done at Brookhaven. And I was working on the cyclotron, which was similar to the Chicago cyclotron.
Zierler:
Uh-huh.
Pondrom:
And I also did some experiments back at Chicago with Jim Cronin and Gene Engels using the Chicago cyclotron. Jim wanted to do some polarization experiments, and when he was at Chicago he worked on a Van de Graaff, so he enlisted me as somebody who knew something about the cyclotron.
Zierler:
And then, how did the opportunity at Madison come about?
Pondrom:
There was a faculty member at Madison named Bill Walker who was a graduate of Highland Park High School [laugh] and who grew up in Dallas, Texas, and who knew my family. And so he was interested—at that time, this was a period when high-energy physics was growing. I mean, during my career there have been sort of feast and famine in the field. And the early ‘60s were a period of feast. And so the Wisconsin group was actually adding faculty and adding budget.
Zierler:
Yeah. So your sense was that, in those years, the Wisconsin Department of Physics was in growth mode?
Pondrom:
Yes, yes.
Zierler:
And where did you fit in on that in terms of the kinds of things they wanted to emphasize?
Pondrom:
Well, the high-energy group was one of the growth areas. The nuclear physics was very strong already at Wisconsin, and material science also very strong.
Zierler:
And who were some of the prominent professors when you first got there?
Pondrom:
Jack Fry, Ugo Camerini, Bill Walker, Bud Good. Then, in theory, there was Bob Sachs and others. So it was a fairly large group.
Zierler:
And did you start taking on graduate students right away?
Pondrom:
Right away.
Zierler:
And so what kinds of students came to you? What kinds of things were they interested in?
Pondrom:
Well, when I was just getting started, it was easy to attract graduate students because I wasn’t that much older than they were.
Zierler:
[laugh] So you’re saying that played to your advantage?
Pondrom:
Yeah, that’s right. It played to my advantage. I had two or three really good students, so one of them is Steve Olsen, who is pretty well known, and another was Peter Limon, who is also pretty well known.
Zierler:
Yeah.
Pondrom:
Those were two of my very early students.
Zierler:
And what kinds of projects were they working on?
Pondrom:
Well, we worked at the Chicago cyclotron. We did some more proton-proton triple scattering experiments.
Zierler:
Now, you’re talking about during summers or leaves of absence? How would you work that out?
Pondrom:
Oh, the commute is not that hard. I only taught one course, so if I taught on Tuesday and Thursday, why, I could drive down and come back. I did a lot of commuting, first to the Chicago cyclotron and then to Argonne. I worked at the Argonne ZGS for a few years, and then I changed over to Fermilab, so continued to commute.
Zierler:
So all of your lab work was essentially off campus? You didn’t have a lab in Madison?
Pondrom:
I did but it was to build equipment to use at the various accelerators. We did not have an accelerator on the campus.
Zierler:
Yeah. So give me a broader sense during these years, what were some of the big research questions you were after? What did you see your research was contributing to sort of in a broader context?
Pondrom:
Well, for the Chicago cyclotron, we did an experiment on time reversal invariance. That was of interest because of the discovery of CP violation, which was done by Jim Cronin and Val Fitch at Brookhaven in 1964. And so CP is T in the CPT theorem.
Zierler:
Mm-hmm.
Pondrom:
So there were a bunch of experiments on time reversal invariants. And we did one at the Chicago cyclotron that was actually a classic. It was on proton-proton triple scattering, so it was a time reversal test in strong interactions. Then I did experiments on hyperon decay at the Cosmotron at Brookhaven, and at the Penn-Princeton accelerator, which had a brief existence. It no longer exists.
Zierler:
Yeah. What happened? Why was it so short lived?
Pondrom:
Budgets.
Zierler:
Uh-huh. It’s not the relative significance of the work that was being done there?
Pondrom:
Well, it was limited in its energy. I think it was a 3 GeV machine, so it was sort of like the Cosmotron. But we did an experiment there—we did two experiments there, actually.
Zierler:
I wonder if you could talk a little bit about your reliance on computers over the course of your career; when did they become a factor, when were they most useful for your research?
Pondrom:
Well, funny you should ask. When I was a graduate student at Chicago, Nicholas Metropolis was there from Los Alamos and he, along with John von Neumann and other people, were busy designing digital computers. But there wasn’t one on the Chicago campus. The digital computer was at Argonne.
Zierler:
By “the,” you mean singular, “the computer”?
Pondrom:
The computer, yes.
Zierler:
[laugh]
Pondrom:
It was at Argonne. And, of course, we all had slide rules. But, for my thesis, I needed to invert an error matrix, so it was, I think, a 6 x 6 error matrix, something like that. So I went to Argonne to invert it on the computer out there. That was my first experience with the computer. I mean, other than that, we had Marchant and Friden calculators that sat on the desk. And some of them would take the square root. If you pushed the square root button the machine would jump up and down. [laugh]
Zierler:
[laugh]
Pondrom:
Yeah. So the Air Force was kind of a hiatus. I didn’t have any real exposure to computers. We got to Nevis, we had an IBM 650 at Nevis, and it read punched tape. And so I did learn how to do some FORTRAN programming on the Nevis computer.
Zierler:
When did it dawn on you that a computer was really a gamechanger, that it was really gonna fundamentally impact how research was conducted?
Pondrom:
It came on us slowly. I think some people have pointed out that we used to read scientific magazines back in those days, and one of them was Popular Mechanics and things like that, Popular Science. There are no computers in any of those magazines. It’s just not mentioned.
Zierler:
Right.
Pondrom:
Nobody saw it coming.
Zierler:
Right.
Pondrom:
Now, in the mid ‘60s at the Chicago cyclotron, we had an online computer, so we were actually acquiring data and processing it in real time from spark chambers, readout of spark chambers, reconstructing events on a digital computer which sat next to the experiment in the cyclotron. So that was in the mid ‘60s, so already computers were starting to be used for data acquisition, in addition to data analysis.
Zierler:
I wonder if you could talk about the Midwest Universities Research Association and your involvement with them?
Pondrom:
Yes. Well, OK. When I came to Wisconsin, it was sort of winding down.
Zierler:
What was its mission?
Pondrom:
I’m not an expert on its history. How come it got established at Stoughton, which is very close to the Madison campus, I actually don’t know.
Zierler:
And what was going on at Stoughton, what was there?
Pondrom:
They had an electron storage ring that they were using as a synchrotron light source. It was a small ring. They had built some other magnets for more sophisticated accelerator design. There was a thing called an FFAG, fixed-focus alternating gradient cyclotron design that they had. They never built that machine. Eventually, they built a larger synchrotron light source—a machine for material science called Aladdin, which was very productive, and it operated for at least 20 years. However, when I first came to Wisconsin, they were trying to build a big accelerator at Stoughton.
Zierler:
How big? You mean to compete on a national level?
Pondrom:
Yeah. To compete on a national level. I don’t recall what the energy was. It was approximately the same time that a 200 GeV proposal was made by Berkeley.
Zierler:
Now, would these have been in direct competition? Would they have been redundant?
Pondrom:
Yes, yes.
Zierler:
So it’s one or the other?
Pondrom:
It’s one or the other.
Zierler:
OK. Now, in retrospect, did Stoughton ever have a fighting chance given that Berkeley threw its hat in the ring?
Pondrom:
Well, it’s very interesting. Ned Goldwasser, who wound up being deputy director of Fermilab, was one of the proponents of MURA.
Zierler:
Why? He thought that the Midwest was just the better spot for this?
Pondrom:
Yeah. I mean, there was certainly a regional competition kind of a thing.
Zierler:
Right, right.
Pondrom:
And he met with Lyndon Johnson when Johnson was president to try to sell the MURA machine. And, why, Goldwasser says—I mean, you’ve probably interviewed Goldwasser, so you know this story.
Zierler:
I have not. Maybe I should get in touch with him.
Pondrom:
[laugh] He said it was a very interesting conversation with the president.
Zierler:
I was not aware that Johnson—I mean, that’s a very high-level conversation to have. I was not aware that Johnson was involved in national-laboratory-type discussions.
Pondrom:
Well, he was, he was. So, the upshot of all this was that MURA was turned down and the Berkeley proposal was thrown to a national competition.
Zierler:
So why was it thrown down? What happened?
Pondrom:
Budgets.
Zierler:
Just budgets?
Pondrom:
Just budgets.
Zierler:
Meaning—
Pondrom:
Johnson said he can’t afford it.
Zierler:
He couldn’t afford this one, but he could afford Berkeley? It was a one or the other, you’re saying?
Pondrom:
I think that’s correct, yes.
Zierler:
Yeah.
Pondrom:
But Berkeley lost, because Berkeley eventually became Fermilab.
Zierler:
Right, right.
Pondrom:
So the Midwest got the machine, it just got a different machine. And the MURA people—I mean, Fred Mills, for instance, was a major player at MURA who became a major staff member at Fermilab. So, the talent stayed in the Midwest.
Pondrom:
[laugh]
[Short Break]
Zierler:
OK. So we’re back. So just to pick up, we were talking about how, in the end, actually Berkeley lost out also and it went to Fermilab.
Pondrom:
That’s correct.
Zierler:
So what was your sense of how that played out? Was that a budgetary decision, too, or was Fermilab just too politically important for it not to go there?
Pondrom:
Well, the Atomic Energy Commission set up a site selection committee. That’s the way it does these things.
Zierler:
Right.
Pondrom:
And the site selection committee toured the country looking at various proposed sites and picked the one at Fermilab. I didn’t serve on that committee, so I didn’t know what it was doing. And I have to say that the existence of MURA was not a reason for me to return to the Midwest. I was interested in other things and didn’t really pay much attention to MURA.
Zierler:
So let’s switch topics a little bit now. I’m curious about what was going on on campus in Madison in the late 1960s. What was your experience like with all of the campus—the protests and things like that?
Pondrom:
Well, it was a very tense time. The Sterling Hall bombing took out my office.
Zierler:
Did it really?
Pondrom:
Yeah. It was in Sterling Hall.
Zierler:
I assume you weren’t there at the time?
Pondrom:
No. But one of my graduate student’s husband was killed.
Zierler:
Oh.
Pondrom:
So, the bomb went off in the early morning hours, and I was wakened by a phone call and went to the scene at something like 3:00 in the morning. So, I have very vivid memories of that period.
Zierler:
Now, before this happened, was your sense that things were so tense on campus that something like this could’ve happened, or this was an out-of-the-blue kind of tragedy?
Pondrom:
Oh, I think it was an out-of-the-blue kind of tragedy, although we certainly had lots of problems. Before that we had many protests, we had a lot of teargas. There was a lot of chaos on the campus, no question.
Zierler:
And was your sense that most of the chaos was coming from the students themselves or from people that were coming from outside to Madison?
Pondrom:
It has to be a little of both in that the bombers were not Madison students.
Zierler:
Mm-hmm.
Pondrom:
So, there are bound to have been some outside agitation, although there was a lot of student support, as well.
Zierler:
What was your sense of why Sterling Hall was targeted?
Pondrom:
It was because the Army Math Research Center was in Sterling Hall, in addition to the physics department, the astronomy department, the nuclear physics laboratory, and all kinds of other things. So it was the Army Math Research Center which they were targeting.
Zierler:
Yeah.
Pondrom:
They thought it was doing bad things on the campus for the army, like helping the Vietnam War.
Zierler:
Yeah, yeah. So how did this impact you in terms of your work? Did you set up a satellite office or did you just have to take a break for a while?
Pondrom:
It was in the summer, and we were in the process of moving to another building. That process was accelerated by the blast. It was in 1970. My own research wasn’t really affected, but nuclear physics was. The big Van de Graaff was completely shut down by the blast.
Zierler:
Yeah, yeah. Were you fearful after this happened?
Pondrom:
No, I wasn’t afraid, but I found it highly inconvenient.
Zierler:
[laugh] Indeed, indeed. And I wonder if you ever had interactions with undergraduates who were angry, and you tried to guide them in what you saw as a more productive way of expressing themselves?
Pondrom:
There was some of that. A physics department is a little bit isolated, insulated from the main protest movement. There was some, and there was some people who were afraid of getting drafted. I had come through the Air Force so that I was not that afraid of the military, but—
Zierler:
Right.
Pondrom:
—I wasn’t supportive of the Vietnam protests.
Zierler:
Yeah, yeah.
Pondrom:
I was not supportive.
Zierler:
Right, right. Because why? Were you in support of the war of you just thought that the protests themselves were counterproductive?
Pondrom:
Well, initially, I was supportive of the war. I think my support of the war diminished, but this last winter I was in Saigon and I got home just before the virus thing closed in on all of us. And the place would be much different if we hadn’t lost the war.
Zierler:
For sure.
Pondrom:
It would be much different. So, it’s one of those things.
Zierler:
Well, let’s move on to your work on the E8 experimental proposal. How did that start?
Pondrom:
Well, Bob March was a colleague at Wisconsin, and I and Tom Devlin from Rutgers, we decided that we would put together a proposal for the new accelerator. And we did, and it ran for 10 years.
Zierler:
What was the proposal? What were you looking to accomplish?
Pondrom:
Well, we had a large program working with the lambda hyperons, so we were going to look for polarization of the lambdas, which we found. We were going to measure a lambda cross section through strong interaction and experiments in hydrogen target. We were going to study lambda beta-decay, so we had a pretty good program fixed. And I have to say that the 200 GeV machine that Bob Wilson built never ran at 200 GeV. It started off at 300 and then it went up to 400, and the higher energy helped the hyperon beam a whole lot because the decay length is much longer, and so you just have much higher intensity beams.
So the main ring was sort of a lemon, but it did get the high energy, and that was certainly a plus for our program. Now, we discovered the polarization of the lambdas in the early running, and this gave rise to the measurement of the magnetic moment of the lambdas, which is like the Garwin-Lederman experiment.
Zierler:
How so? How was it like the Garwin-Lederman experiment?
Pondrom:
Well, the magnetic moment moves in the magnetic field, and the decay distribution of the daughters from lambda decay move with the spin. So, by looking at the decay, you know the direction of the spin, and that’s just what happens in muon decay, as well. Thus, it’s similar, the exact similarity. So, as the lambda moves through the magnet, if it’s produced polarized, the polarization is perpendicular to the plane of production, it moves through the magnet, it processes the distribution and changes direction. If it goes outside the magnet the spin doesn’t move anymore, it just cruises along.
And so, by reversing the magnet which is easy to do with a neutral bearing, and by reversing the production plane direction with the proton beam, you can take data in such a way that systematic effects are taken out and the polarization was discovered. It is not a very big effect. It’s about 10%, but it’s enough.
So we measured the lambda magnetic moment to unprecedented precision at that time, and also in the neutral beam were cascade zeros, and so we measured the cascade zero magnetic moment, and then we made a proposal for changing the configuration of the neutral channels so that we could get out a charged hyperon beam. And we did that, and the charged hyperons were also polarized, so we measured a bunch of magnetic moments there, including the omega minus. So it turned out to be a long and very productive program.
Zierler:
Over 10 years you were involved in that, right?
Pondrom:
Over 10 years, yeah, with all of these various things.
Zierler:
Now, at what point did you join in on the CDF collaboration?
Pondrom:
At the end. 1976 is the proposal by Peter McIntyre and Carlo Rubbia and Dave Cline to do a pbar-p experiment at Fermilab or CERN to get enough energy to make the weak intermediate bosons. Now, we have to go back a little bit.
Zierler:
Yeah.
Pondrom:
Steve Weinberg’s famous paper was in 1967.
Zierler:
Which paper is this?
Pondrom:
It has the very modest title, A Model of Leptons.
Zierler:
[laugh] Right. But it has much bigger things to say.
Pondrom:
It has much bigger things to say, yes. [laugh] It is the electroweak theory.
Zierler:
Yeah, right.
Pondrom:
And the electroweak LaGrangian is in that paper with all of the Higgs mechanism and all of the whole thing, and the prediction of the neutral currents and the prediction of the masses of the W and the Z based on the Weinberg angle. Now, the neutral currents were then discovered—this was ‘67 that was Weinberg’s paper—and neutral currents were discovered something like ‘73 at Gargamelle. The neutral current is about a 20% effect in neutrinos. About 20% of the neutrino interactions don’t have a charged lepton in the final state. And you would think that this would be a signal that would just knock you over, but it was very hard to establish that it was really happening because of the problem with backgrounds. The neutron backgrounds are the worry, and the neutrons—
Zierler:
This is a signal-to-noise issue?
Pondrom:
Yeah.
Zierler:
Yeah.
Pondrom:
Yeah. And the neutron background actually comes from neutrino interactions, so that you can’t get away from it. [laugh] So the problem is to separate the neutron background from the neutrino neutral currents.
Zierler:
Yep.
Pondrom:
And they finally thought they did it. There are a number of tricks that they used, but at the basic level, because the neutrino beam is, in fact, the source of the neutrons, as well, as the source of the neutral current, it’s a tough problem. Anyhow, it’s now, of course, widely accepted. But once you got that cross section, you could feed that back into Mr. Weinberg’s paper and get an estimate of the masses of the W and the Z. And the result was between 50 and 100 GeV.
Now, within that mass range, no fixed target accelerator that existed would come close. The energy in the center of mass from Fermilab is about 25 lgel/ GeV. So the proposal of Cline and company was to build a pbar source and use the main ring as a collider with Ps and p-bars. Now, Dave Cline was a colleague of mine at Wisconsin, so I had obvious contact with him. And my name’s not on the proposal, but I did a fair amount of work on various aspects of it. The main ring was a lousy storage ring. It had a lot of problems. And I actually worked on some of the accelerator division experiments at Fermilab studying storage of beam in the main ring.
Zierler:
Now, was this ring the first of this kind? Were some of the problems related to the fact that this had never really been done before?
Pondrom:
Well, Wilson’s design of the magnets was marginal. He was trying to save money and it wound up that I think almost all the magnets had to be replaced. But the endpoint machine was not as good a machine as the SPS. That’s the bottom line.
Zierler:
Yeah.
Pondrom:
So the main ring, as I say, it got to 400 GeV at fixed target, which helped the fixed target program a lot. But it wasn’t well enough designed to be a storage ring. The beams just wouldn’t stay stably in the machine for hours on end.
Zierler:
Right, right.
Pondrom:
Then, CERN also had an advantage in that it had Simon van der Meer, who was a highly-skilled guy, and he invented this stochastic cooling process for the antiprotons. There were two ways to cool the antiprotons that were out there at the time. One was called electron cooling, which was invented by Sasha Skrinsky in Novosibirsk, and the other was stochastic cooling, which was invented by Simon van der Meer at CERN. Stochastic cooling is a thing where you take a pair of plates and you sense where the beam is off center, and you send the signal across the ring to another place to correct it.
Zierler:
Mm-hmm.
Pondrom:
And the cooling time is proportional to the square root of the number of particles, which is where the stochastic term comes from. So, the more beam you have, the longer it takes to cool it. Electron cooling is really just dE/dx. The antiprotons and the electrons are going parallel to each other with the same velocity. The electrons are cooler than antiprotons. The antiprotons bump into the electrons and lose energy. [laugh]
So the electrons warm up and the antiprotons cool down. OK. Now this process actually was successfully used in the recycler and later versions of the Fermilab pbar-p collider. But in the early days, it was not pursued. And the accumulators, both in CERN and eventually Fermilab used stochastic cooling.
Zierler:
Now, Lee, I just want to make sure I have this correct. Is this a separate project from your collaboration with Stan Ecklund or this is all the same?
Pondrom:
Well, with Stan Ecklund, we were studying the storage of protons in the main ring.
Zierler:
Right.
Pondrom:
So we would accelerate the beam to a couple of hundred GeV and then we would turn off the RF—well, you don’t really turn the RF off. What you do is you change the phase so that the mean acceleration voltage on the beam is zero, but the RF is still on and the beam is still bunched.
Zierler:
OK.
Pondrom:
And you watch how the bunches behave as it goes around the machine, and you hope that the bunches don’t grow and the beam isn’t lost, and it stays there for hours, because that’s what a storage ring is supposed to do.
Zierler:
Right.
Pondrom:
And that was not the case. And there were high losses, and the bunches were unstable. So, we never were satisfied that we could use the main ring as a storage ring.
Zierler:
Now, what’s the transition in terms of how the Tevatron came about?
Pondrom:
Wilson wanted to build a superconducting machine from the beginning.
Zierler:
You mean, from scratch or that’s what he—
Pondrom:
From scratch.
Zierler:
—always wanted to do? From scratch.
Pondrom:
From scratch. $250 million dollars was the amount of money that he was given to build Fermilab. OK?
Zierler:
Right.
Pondrom:
And he wanted to scrape off a little bit and lay it to one side to build superconducting magnets. He wanted to do that from the beginning.
Zierler:
And what do you think he was after? What was Wilson interested in with regard to superconducting?
Pondrom:
Well, he just wanted a doubler. He wanted to double the energy. He is a machine builder, Wilson is.
Zierler:
Yeah.
Pondrom:
So was Lawrence. I mean, these guys—you know the famous story of Lawrence never discovered artificial radioactivity because the switch that turned the cyclotron on and off also turned off the high voltage on the counters.
Zierler:
[laugh]
Pondrom:
It’s true! [laugh]
Zierler:
So it was there, they just never detected it?
Pondrom:
It was there, but, you know, the counters kept on counting after the machine was down, but they never found that.
Zierler:
That’s great! [laugh]
Pondrom:
Well, anyhow, it was discovered by Joliot-Curie, right? Anyhow, where was I? Oh, Wilson and the doubler. So, he just wanted to build a machine, and his early superconducting magnets were lacking, I think it’s fair to say.
Zierler:
Yeah.
Pondrom:
So, when Leon became lab director, he was the second director of the lab. When I was working with Stan Ecklund and Russ Huson was head of the accelerator division, it was Wilson’s last year as lab director, so the lab was in transition.
Zierler:
Uh-huh.
Pondrom:
So, the laboratory was kind of undergoing a transition of leadership and goals and so forth. Leon came in and he decided that the main ring would be an injector into the Tevatron, but that the Tevatron would be the machine—the unbuilt Tevatron would be the machine for the pbar-p collider.
Zierler:
Sure.
Pondrom:
And, of course, building the Tevatron magnets was quite a task, but it was eventually successfully carried out. And the Tevatron itself was an excellent machine.
Zierler:
Yeah. What were some of the big questions that the Tevatron was going to answer? What was the idea?
Pondrom:
For the fixed target program, there wasn’t much. The Tevatron actually didn’t perform as a fixed target machine for very long. The collider was always the main thing, and, of course, the collider has this huge increase in center of mass energy. So, although the W and the Z were discovered at CERN, they were copiously produced at Fermilab.
Zierler:
Mm-hmm.
Pondrom:
And Fermilab discovered the top quark, which is probably its main contribution to particle physics. But the 2 TeV and the center of mass, that was a big deal.
Zierler:
Now, was Lederman also the driving force between the antiproton source?
Pondrom:
John Peoples was the guy who built it.
Zierler:
Uh-huh.
Pondrom:
And he succeeded Lederman as lab director. And I actually asked John Peoples about some of this in preparation for this talk, and he sent me about a six-page document from his top of his head on how all of this stuff took place. So, I did some homework. [laugh]
Zierler:
Yeah. And what about the CDF detector, who was behind that?
Pondrom:
You know, that’s a funny thing. I think there really never was a formal proposal for the CDF detector. It was part of the fallout of the Cline, McIntyre, Rubbia proposal, the ‘76 proposal for the pbar-p collider. This spawned a number of workshops and things, and somehow Alvin Tollestrup was asked to lead a group to build a collider detector for the Fermilab program. And I was one of the early members of that collaboration.
Zierler:
Now, I wonder if you could talk about, from your vantagepoint, the rise and fall of the SSC, right? You’re looking at this from your work at Fermilab. What’s your perspective in terms of when it was initially proposed and when it seemed like this was really gonna happen, in what way did you see that this was going to affect what was going on at Fermilab, if, in fact, that the SSC had gone through?
Pondrom:
OK. Well, so this is all tied up with the Wojcicki panel, which I served on. This was in 1983. You see, Carlo went to CERN in the late ‘70s and organized the UA1 detector collaboration and organized the construction with other support, of course, of the antiproton source. And the project at CERN was successful in making both the W+/- and the Z. Oh, it was tough going.
Zierler:
Yeah.
Pondrom:
They were at 540 GeV. And CF ran for calibration purposes down at that energy. It was miserable. [laugh] It was much harder than running at 2 TeV, believe me. If you reread the proposal of McIntyre, Cline, and Rubbia, the luminosity that they projected for the pbar-p collider is pretty much on target. They said that they could probably get a few 1029 cm-2 sec-1 per centimeter squared per second. And that is actually what the CERN machine ran at, at least initially, the first two or three years. The cross-sections, however, for W and Z production were 100 times too big in their proposal.
Zierler:
Mm-hmm.
Pondrom:
So the signals were a lot harder to find.
Zierler:
Yeah.
Pondrom:
And I think they wound up with 3 Zs; 3, OK? [laugh] At the Fermilab at CDF, the Z was such a strong signal. It’s just a wonderful resonance. It’s just a beautiful thing. But they just barely found it. But, anyhow, this is kind of a background for the US program. OK?
Zierler:
Right.
Pondrom:
We are sort of mired in the mud. We don’t really have a working storage ring. We didn’t get a Nobel Prize. What should we do?
Zierler:
And the guiding idea here was that the big questions were not going to be answered at Fermilab, that we needed a new site, is that the basic gist?
Pondrom:
Yeah. That’s the basic idea is that we needed a leapfrog in energy to be competitive.
Zierler:
And so why not just build where Fermilab already was? Why do we need a new site?
Pondrom:
Yeah, yeah, yeah. That’s fine. [It was] Charlie Baltay [at] the first Snowmass Summer Study in 1982 that the American Physical Society sponsored—not the AEC.
Zierler:
Yeah.
Pondrom:
He organized this to study what high-energy physics in the United States should be doing, OK? The future.
Zierler:
Right.
Pondrom:
OK. And then, after that—well, one of the things that that—one of the proposals that came out of that summer study was called a VBA, the very big accelerator—
Zierler:
[laugh]
Pondrom:
—which was also called the Desertron because it had to be built in Arizona it was so big. Then the Wojcicki panel was formed the next year.
Zierler:
And what is Wojcicki? Is that a place name?
Pondrom:
Oh, that’s the name of Stan Wojcicki. He’s a person.
Zierler:
Oh, I see. OK.
Pondrom:
OK. And he has two famous daughters, Susan Wojcicki is a high-ranking member of Google, and Anne Wojcicki is president of 23andMe.
Zierler:
Oh, OK. All right. Good to know.
Pondrom:
And was the former wife of Sergey Brin.
Zierler:
Uh-huh. [laugh] OK.
Pondrom:
OK? [laugh] So Stan Wojcicki and his wife are famous parents.
Zierler:
Yeah.
Pondrom:
They are presumably feeling no pain.
Zierler:
Right.
Pondrom:
However, back to the Wojcicki panel. He is a professor at Stanford.
Zierler:
Right. OK.
Pondrom:
And Google was probably invented in his garage, as far as I know.
Zierler:
[laugh]
Pondrom:
Susan’s been in the news recently because of this controversy over—it’s YouTube, I think. Is Google the parent company of YouTube?
Zierler:
It is, yeah.
Pondrom:
Yes. And Susan runs YouTube, and there was some controversy recently about YouTube not allowing some program to go on. I don’t remember what it was.
Zierler:
Oh, OK. I didn’t know about that.
Pondrom:
Susan was in the national news. OK. So the Wojcicki subpanel, we met—I was on it, and we met for six months. And its role was to be an official advisor through HEPAP, the High Energy Physics Advisory Panel, to the AEC, or to the DOE at that time.
Zierler:
Right.
Pondrom:
So it was an official advisory instead of the study group which was organized by Charlie Baltay. And this panel authorized the further study of a 20 TeV machine. It authorized the completion of the linear collider at SLAC. It authorized an upgrade for the Cornell storage rings. It recommended the decommissioning of ISABELLE. OK. So, now, out of those recommendations, we have the SLAC linear collider, which, now, this is a time—this is 1983.
Zierler:
Yeah.
Pondrom:
LEP was—they were still just digging the LEP tunnel.
Zierler:
Right.
Pondrom:
There was hope that the linear collider at SLAC would steal a march on LEP and start making the Z resonance before LEP did. OK. Now, it turns out that didn’t occur because of lots of troubles with getting the SLAC linear collider to work.
Zierler:
So they wanted to, they just weren’t able to pull it off?
Pondrom:
They weren’t able to pull it off. Now, what saved the SLAC linear collider is the polarized source, which was built by my colleague, Dick Prepost here at Wisconsin. He had 80% polarized electrons coming out of this source, and those electrons collided with the positrons 50 GeV on 50 GeV. And that polarization was a big deal in studying characteristics of the electroweak theory. And LEP didn’t have that, so that compensated for the difference in luminosity, which was considerable.
Zierler:
Right.
Pondrom:
OK. But that’s another story. But, anyhow, the central design group for the SSC came out of the recommendations of the Wojcicki panel.
Zierler:
And what was the basic recommendation to create the SSC?
Pondrom:
Well, I don’t remember the language, but it was that the study group should be established to pursue the design and construction of a 20 TeV machine.
Zierler:
Right, right. And baked into that recommendation was the idea that a new site would be required because of the scope and size of this thing?
Pondrom:
Eventually, yes.
Zierler:
Yeah.
Pondrom:
Yes. You know, Fermilab was in the running for the site.
Zierler:
Right.
Pondrom:
And there’s much debate as to whether, if it had gone there, it would’ve saved the project.
Zierler:
And who’s the audience for this proposal? What minds need to be changed to make this happen?
Pondrom:
What—I’m sorry?
Zierler:
Who’s the audience of the proposal? You make this proposal, who is it directed at?
Pondrom:
Oh, you make it to the Department of Energy.
Zierler:
OK. It’s strictly the Department of Energy that’s going to be considering this?
Pondrom:
That’s right.
Zierler:
OK. As a scientific matter, right, you’re asking for a whole lot of money, DOE needs to be convinced that this is worth it, right?
Pondrom:
That’s right, yeah.
Zierler:
So, what’s the case? What’s the case you’re making that the budgetary investment is worth it for the SSC?
Pondrom:
Well, I’d have to think back on what it was we said. Obviously, our arguments wound up not being successful.
Zierler:
Well, in the end, though…the trajectory was is that it was going to work, right?
Pondrom:
Yes. Right.
Zierler:
I mean, I talked to Roy Schwitters about this in great detail, and it was—
Pondrom:
Yes.
Zierler:
—he went down, he was all set to do this, it was on that trajectory and then, it wasn’t about the science, it was about the money.
Pondrom:
Well, Roy certainly knows better than I do.
Zierler:
But was he on the advisory panel?
Pondrom:
I don’t think Roy was a member of the Wojcicki panel. No.
Zierler:
Yeah. I don’t think he was, either. I think he came on afterwards.
Pondrom:
I don’t think he was. John Adams was from CERN.
Zierler:
Yeah.
Pondrom:
And Carlo might’ve been on. Yes he was.
Zierler:
Well, so, in terms of the—if the specific reasoning doesn’t come to you right now, I guess a more focused question, in terms of the proposal was, was the emphasis more on what the existing national laboratory structure could not do? Was it about, we just can’t do this under current circumstances, or was it more about, you know, each of the other national labs has their mission and this is separate from that, and that’s why we need a new center?
Pondrom:
Well, I would have to refresh my memory on exactly what it was we—
Zierler:
OK.
Pondrom:
No, it was a necessity for a new center. It was a necessity for a new energy regime.
Zierler:
Right, right. That theoretically could have been tacked onto an existing laboratory?
Pondrom:
Theoretically, exactly.
Zierler:
Right.
Pondrom:
It wasn’t the desire for a new laboratory.
Zierler:
OK.
Pondrom:
It was the desire for a new energy regime.
Zierler:
Good. Right.
Pondrom:
And the arguments for the new energy regime were probably things like supersymmetry, which was—it’s always a popular argument that gets dragged out and has never been found.
Zierler:
[laugh] Not yet.
Pondrom:
String theory played no role, I believe.
Zierler:
Well, let’s go back to the vantagepoint of Fermilab, right? What’s the sentiment in 1989 in Fermilab when the SSC looks like it’s the real deal and it’s going to happen? Is it more excitement? Is there apprehension about what this means for Fermilab’s budget? What was your sense of how SSC was regarded from Fermilab?
Pondrom:
Well, Fermilab was not in a strong position. URA, the governing body of Fermilab, was also the governing body of the SSC, so the management was the same operation. Now, they tried to have two different boards of overseers, one for Fermilab and one for the SSC, but the parent organization was the same. Several accelerator experts from Fermilab went to the SSC, Helen Edwards, for example, went to the SSC.
Zierler:
Right.
Pondrom:
So John Peoples, who was the director of Fermilab at that time, lost a fair amount of staff. Peter Limon, my old graduate student, went to the SSC. Fermilab was sort of on the ropes. The collider program was just getting started. The Tevatron actually started working around 1985.
Zierler:
Yeah. And so, then, by 1993, when the SSC was sort of kaput, right, how did that affect Fermilab? Did that have a—
Pondrom:
It did, it did.
Zierler:
In a positive way? Did it have a galvanizing effect on Fermilab?
Pondrom:
The main injector got built.
Zierler:
Right, right.
Pondrom:
Which wouldn’t have happened—I don’t think that would’ve happened if the SSC had kept going.
Zierler:
But the main injector was not a replacement for the SSC. It wasn’t proposed that this would do what the SSC was built to do?
Pondrom:
No, no, no, no. The main injector is a replacement for the main ring.
Zierler:
Yeah.
Pondrom:
And it got the main ring out of the main ring tunnel.
Zierler:
Uh-huh. And was that more successful than the first go round?
Pondrom:
That was a big deal for the success of the Tevatron collider.
Zierler:
Right.
Pondrom:
It was a big deal.
Zierler:
How so?
Pondrom:
Well, the main ring was just not an effective, high-intensity machine. It had to deliver protons to the pbar source to make pbars, they had to be stored and cooled in the accumulator, in the de-buncher. Then they had to be reinjected into the main ring and then accelerated up into the Tevatron. And the main ring went through the detectors. CDF had a bypass. The main ring went above the detector and down again.
And for DZero, the other experiment, the main ring went right through the calorimeter. It just went right through the detector itself. So this was not the best of circumstances, so the main injector is higher intensity, it’s got better emittance, it’s got a faster cycle time, it’s able to make antiprotons and then capture antiprotons from the source. The choreography is that the antiprotons, which are produced at a target, get captured into a machine that’s called a de-buncher, which spreads the beam out in a circle.
Zierler:
Uh-huh.
Pondrom:
Then they go into the accumulator where the stochastic cooling takes place. Then they go into the recycler, which is this permanent magnet machine that sits above the main injector. And the recycler has the electron cooling in it. It also has stochastic cooling in it. It increases the intensity of the p-bars by a factor of, like, three or four, so it’s a big deal.
Zierler:
Right, right.
Pondrom:
And all of this stuff is out of the main ring tunnel. So, after the recycler, the pbars go into the main injector, and from the main injector they go into the Tevatron.
Zierler:
Now, I want to ask at this time, just to get back to your duties in Madison, what was your—I mean, you’re spending a lot of time at Fermilab, of course, during these years. Are you commuting the whole time? Are you still keeping up with teaching courses in Madison and it’s just a back and forth situation this whole time?
Pondrom:
Yeah, yeah.
Zierler:
And are your graduate students mostly with you at Fermilab or are they mostly in Madison?
Pondrom:
Well, it’s a mix. If they’re still in classes they are mostly in Madison, but if they’re out of classes—I had a house in Warrenville. I rented a house for 20 years.
Zierler:
Kind of halfway between?
Pondrom:
No. It was right next to the lab.
Zierler:
[laugh] Oh, OK.
Pondrom:
It was right next to the lab.
Zierler:
Yeah. And I’m just curious, in terms of service to the department, I mean, it’s a little unique, right, to be spending so much time away from campus, so obviously the physics department saw it in their interest for you to be this deeply engaged with what was going on at Fermilab. And then, the follow-on question to that, obviously, is: Did you ever think simply of becoming a fulltime employee at Fermilab?
Pondrom:
No, I didn’t. [laugh] I would take sabbatical leaves and things like that. And I was on the Fermilab payroll off and on throughout the period, but I never considered joining the laboratory.
Zierler:
Because you liked keeping a hand in the academic environment?
Pondrom:
I like keeping a hand in the academic world. I served 3 years as Chairman of the Physics Department.
Zierler:
And we really haven’t talked much about teaching. Did you teach undergraduate courses?
Pondrom:
Sure. But smaller advanced courses for majors, not the big introductory courses.
Zierler:
What were your favorite courses to teach undergraduates?
Pondrom:
Well, modern physics, introductory quantum mechanics, classical mechanics, electricity and magnetism. I taught all of those, of course at sort of junior/senior level.
Zierler:
And these were for physics majors mostly?
Pondrom:
These were for physics majors, yeah.
Zierler:
So let’s now talk about the tail end of Tevatron. What was your sense of why it ended and when it ended when it did?
Pondrom:
Well, it ended because of the LAC, for one thing. It ended in 2011. We were looking for the Higgs. Once we knew what the mass was, we could probably have had a chance of seeing it at Fermilab. Without any knowledge of the mass, the cross sections were so small that we could set a limit on certain decay modes, but we didn’t really have the luminosity to do a broad search.
Zierler:
And so how does this connect to the decision to end Tevatron?
Pondrom:
Well, again, it’s budgets.
Zierler:
Yeah.
Pondrom:
The two big detectors at the LAC that had US support, CMS and ATLAS, had needs for the operating expenses of the Tevatron. It cost $25 million a year to run the Tevatron.
Zierler:
Right, right. So, I think, now that we’re getting to more recent times, I want to ask a little bit about your service in high-energy physics. What do you think were some of the most impactful advisory roles and committees that you’ve served on over the course of your career?
Pondrom:
Well, certainly the Wojcicki Committee is one of the big ones.
Zierler:
Yeah.
Pondrom:
When I was on ICFA, the International Committee for Future Accelerators, it was kind of during a lull period. The ICFA didn’t have a whole lot to do. I tried to get ICFA to support the SSC. There was a famous meeting in Japan with which I proposed that ICFA formally support the SSC, which Carlisle and other people from CERN were in the audience and, in fact, on the committee. And so this was one of my experiences in politics.
When I was promoting the project, I would go to Washington. And my local congressman was Bob Kastenmeier. Bob was a Democrat, and I would go to the Rayburn Building and try to knock on doors and get support for the SSC. And so Kastenmeier said, “Well, if you need an office you can use mine. And you can put your coat here and use my telephone, and my secretaries might help you set up appointments and things like that, and feel at home.” So I said, “Well, thank you very much, Bob.” And I did some of that. And then, when time came to vote for the SSC, he voted against it. [laugh]
Zierler:
[laugh] That’s why he was so nice to you.
Pondrom:
But that’s my lesson in politics. I said, well, maybe I better find another line of work.
Zierler:
[laugh] That’s great, that’s great. So, Lee, a broader question, so what do you think was lost as a result of the SSC never having been completed?
Pondrom:
We lost our role as the leader in the field. There’s no question.
Zierler:
No, but beyond that, I mean, were things in physics—were there things that could’ve been discovered that have not yet as a result of SSC not being built? Or do you feel like that work was sufficiently—I don’t know what the right word is—thrown off into other labs and other accelerators, and nothing was lost as far as discovery is concerned?
Pondrom:
Well, the LAC is doing what the SSC would’ve done, but the SSC was well ahead of it. And if it had stayed on schedule, the SSC would’ve started running in the ‘90s.
Zierler:
Right, right. So you see the—
Pondrom:
And the LAC didn’t run until 10 or 15 years later.
Zierler:
So that’s a matter of timing. In terms of what the SSC and the LAC were both designed to do, they would’ve essentially been redundant, is that your sense?
Pondrom:
Yes, yes.
Zierler:
OK. So then, I guess, to reframe my question about what was lost, what’s significant about those lost 10 or 15 years? What’s the significance in that, or is there not one really at the end of the day?
Pondrom:
Well, national pride. Personally, I don’t want to work at CERN.
Zierler:
[laugh] You’re an American, you want to be in the United States.
Pondrom:
That’s right.
Zierler:
Yep.
Pondrom:
In fact, I’ve never worked at CERN. And for years I never went to CERN, but eventually I found it necessary to go. But I think particle physics is now a mature field. The whole development took place in the 50 years that I was involved in it.
Zierler:
Yeah.
Pondrom:
And I don’t see that there’s a whole lot left to learn.
Zierler:
So is that to say that an SSC 2.0 is not really in the cards, as far as you can tell?
Pondrom:
I think it’s not really in the cards. That’s true.
Zierler:
And, obviously, there’s hardly the budgetary appetite for that. But in terms of the science, is it really not justified at this point?
Pondrom:
Well, I don’t know. Maybe not justified is a little bit too strong, but there’s no obvious reason why a higher-energy machine is needed at this point. I think, for instance, there’s a detailed machine that you can build that’ll study the Higgs. That’s probably an electron positron collider. Probably you can build a machine that will make the Z at a high enough energy that the Z can radiate a Higgs. So, you have a Z plus a Higgs in the final state, and this gives you a very pure sample for studying the characteristics of the Higgs. It’s being studied at the LAC, but the signal is not that clean, so that may be a future machine. And I think there’s an interest in building that in Japan.
Zierler:
So that does beg the question, then, without the need for—
Pondrom:
That’s a—
Zierler:
Go ahead.
Pondrom:
That has a specific goal, you see. That’s a machine that would be built specifically to study the characteristics of a particle that is known to exist.
Zierler:
Right, right. So, beyond that particular endeavor, then, it does beg the question, what do you see as the future in high-energy physics? You say it’s a mature field, right? Where is it headed now in maturity?
Pondrom:
Well, people are beginning to be interested in astrophysics and I think that talent is leaving the field, actually. I think this maturity, it no longer attracts the skills. Look, for 50 years it had very interesting questions. It had support from funding sources, sufficient support, and it had the talented people in it to solve the problems. And so it’s a happy story. The problems were solved, as I see it. So maybe now we should—the talented people should go into virology—
Zierler:
[laugh]
Pondrom:
—instead of into particle physics, because look at the mess we’re in.
Zierler:
That’s right. You said it. So, I guess that sort of preempts my next question, which is: If you see a really talented young graduate student come to you and say, “I want to study high-energy physics,” at the end of the day would you counsel against that?
Pondrom:
No. If that’s what they really want to do I wouldn’t counsel against it.
Zierler:
But that suggests that there’s careers that still can be made in high-energy physics and—
Pondrom:
I think there’s still a career to be made in high-energy physics, yes.
Zierler:
OK.
Pondrom:
But I think that its appeal is not as broad as it was.
Zierler:
Right, right.
Pondrom:
You know, I’d like to point out that there are some interesting things in this business. Quantum mechanics has very interesting projections, and particle physics has contributed to these things.
Zierler:
Right.
Pondrom:
The first one was the K-Kbar mixing, where the K and the Kbar decay into the K-long and the K-short. So, there are four different particles. And the conversation is like charge, it’s called hypercharge, which the K and the Kbar have opposite hypercharge. They’re neutrals. So, you can describe it as four different fields and they mix, and the mixing occurs as the particle goes along. And this leads to really very interesting phenomena. It’s all quantum mechanics.
Then special machines were built to study the B-Bbar system. The Upsilon(4S) decays into B-Bbar, two heavy quark mesons. The B and the Bbar can be charged, B+, B-, or they can be neutral, B and Bbar. The B and the Bbar neutral mix, like the K and the Kbar, OK? Now, you make the Upsilon(4S), its odd undercharged conjugation, so as the B and the Bbar separate, they can’t mix because it has to be odd under C, but when one of them decays, it says it’s a B or a Bbar from its decay, then the other one is unlocked and can mix. And this really happens! OK?
Zierler:
[laugh]
Pondrom:
And these two things are six feet apart, and it’s this quantum entanglement stuff, and I think it’s really interesting!
Zierler:
Yeah.
Pondrom:
And that’s part of particle physics. Now, such things—the relativistic theory can’t explain this, so there’s a gap between causality—this drove Einstein nuts—causality and nonrelativistic quantum mechanics and this quantum entanglement phenomena. The B-Bbar system is just a beautiful example of that.
Zierler:
Yeah.
Pondrom:
Well, OK, I mean, I think this is a valuable part of the culture is this kind of thing. It’s a natural phenomenon we still really don’t understand. Quantum mechanics can describe it, but it can’t explain it.
Zierler:
Yeah. And you think that’s going to be true indefinitely, or there’s some breakthrough that will allow it to explain it?
Pondrom:
Well, that’s over my pay grade, but hopefully somebody will figure out how to put causality into nonrelativistic quantum mechanics. Now, it’s interesting that a lot of the quantum entanglement experiments involve photons.
Zierler:
Yeah.
Pondrom:
Yeah. And there’s no such thing as a nonrelativistic photon. [laugh]
Zierler:
[laugh]
Pondrom:
In fact, there’s no such thing as a photon wave function really.
Zierler:
So, in order for that—I mean, I can’t help myself—but if that were to happen, right, if quantum mechanics could do that, would that be a “eureka moment,” a spark of genius? Is that a matter of quantum computing? Is that a matter of the technology improving?
Pondrom:
No, no. It’s a spark of genius.
Zierler:
Yeah.
Pondrom:
No, no.
Zierler:
Good. Maybe that’s reason enough.
Pondrom:
This kind of stuff is fun, and you have to have a certain level of sophistication in order to appreciate it.
Zierler:
Well, Lee, the last item I want to touch on is—I’m absolutely fascinated by your second career as a writer. I want to know about your book, The Soviet Atomic Project—
Pondrom:
Yeah.
Zierler:
—and how you got involved in that topic. And, first of all, where’d you learn to read and write in Russian?
Pondrom:
I learned in the Air Force. At Wright-Patterson there was a civilian technician who was a Russian émigré who decided he would give language lessons to a bunch of lieutenants who didn’t seem to be doing much. [laugh]
Zierler:
[laugh]
Pondrom:
So, I learned Russian and I kept it up. I never really got in the translation game. I did try it once when I was at Columbia. The APS—the AIP in those days, had a big machinery translating scientific papers from Soviet journals. It stopped that, but it did have a big operation for a while. But I never did participate in that.
At the early stages of Fermilab around 1970, there was a large collection of Soviet physicists at the lab, came over from mostly Dubna, and I knew some of them. In fact, Steve Olsen, who was just finishing as my graduate student, was working in that group with the Russians. So, I got interested in them, and my first visit to Dubna was in 1970. So, I’ve kept it up. I’ve had tutors. And my Russian technical reading is very good. I can read the stuff without any problem. My conversation is not so bad but not so great.
Zierler:
Now, was your sense that you were uncovering things that were not known to both American and Russian historians because of your technical knowledge and your language ability?
Pondrom:
Yeah. Well, I approached the project from a different point of view, I think, from historians.
Zierler:
What was your main goal? What did you want to accomplish with this project?
Pondrom:
Well, my main goal really was to show that, despite the working conditions, which were severe, that the Soviet physicists were able to be productive. And that’s true of the musicians, too. The Madison Symphony Orchestra put on a program about, I think, Dmitri Shostakovich and how he struggled during the period of Stalin. And this was very similar to the physicists. The people, if they’re determined to accomplish something, can do it despite conditions like the coronavirus.
Zierler:
Well, on that point, I want to ask you a specific question. I’m sure you’re aware of this particular line of reasoning among a certain group of historians, and that is – one of the primary motivations in Truman deciding to drop the bomb in Hiroshima and Nagasaki was not actually to end the war there, it was really to show Stalin what the United States was capable of. In other words, the United States was already thinking about the beginning of the Cold War even before the war against the Japanese had ended.
Pondrom:
Yeah.
Zierler:
And, in fact, what happened as a result was the lesson that Stalin drew was not to cower before the American nuclear arsenal but was to say, hey, this is really possible. If they can do it, we can do it also.
Pondrom:
That’s right.
Zierler:
And that was the galvanizing effect. Would you say, from your vantagepoint, that makes sense to you?
Pondrom:
Yes, yes, yes. That’s definitely true.
Zierler:
And what, in terms of the people that you talk to and the documents that you’ve read and written about, convinces you that that’s the correct historical interpretation?
Pondrom:
Well, there is a collection of documents which is available online which I used extensively, which was set up by Alex Wellerstein, this man that I’ve mentioned to you that was at the AIP for a while, and is now at the Stevens Institute in New Jersey. Alex obtained, I don’t know how, these documents that were put together by people at Sarov, which is the Russian equivalent of Los Alamos.
Zierler:
Mm-hmm.
Pondrom:
During the project Sarov was called Arzamas-16. And Arzamas-16 is still a closed city. I tried to get in there without any luck. [laugh]
Zierler:
[laugh]
Pondrom:
In any case, from Arzamas-16 they have—it must be 1000 pages. It’s a very long object. It’s online. It’s been put online by Alex. It’s all in Russian. And it’s all of the documents that these guys could get their hands on which pertain to the project from the Soviet archives. And they’re transcribed. If it’s a handwritten document, they transcribed it. And it’s all uniform. It’s relatively easy to read if you read the language. Handwritten Russian is pretty tough, but these guys handled it OK.
So, anyway, that’s a major source. It covers the period from the early ‘40s to the mid ‘50s, and it’s all of the notes between Stalin and Kurchatov and Beria and all of these characters. And it’s from that that I concluded just what you said. You said it very well, that Stalin became determined that he would have it, that it was—it was a political thing. He was not gonna get pushed around.
Zierler:
And to what extent did Stalin rely on captured German physicists to make this happen? Did you see it mostly as a domestic Soviet project, or was the reliance on German physics expertise really central to the Soviet effort?
Pondrom:
No. That’s sort of interesting. The Germans that went to the Soviet Union after the war were, for the most part, experimenters. The allied powers precluded Germany from doing any nuclear physics after the war, so people who wanted to continue work either had to go to the West, or they had to go to the Soviet Union. And some of them had been in the Soviet Union in the ‘30s, and so they kind of knew their way around. Some of them were sort of communist sympathizers. Mostly, though, they were indifferent. And they were, as I say, experimenters.
The main contributor to the Soviet project was a chemist. His name is Nikolaus Riehl, and he has written a book called Ten Years in a Golden Cage, about his life in Russia during the Stalin era. He’s responsible for refining the uranium. Not the isotope separation but the uranium, natural uranium, refining it after it comes out of the mine so that the quality of the uranium is sufficient for a reactor to work. And the first reactor, which went critical in 1946, was with uranium that was purified by Nikolaus Riehl.
So that tells you that, in a way, the German expertise for the project was in instrumentation, it was in metallurgy. The German chemical industry was superior to the Soviet. German engineering was superior. Germany had reparations to pay the Soviet Union for the destruction of the war. These reparations were taken out of East Germany to support the atomic project. So that’s the way Germany helped. Things like oscilloscopes and voltage meters and all that kind of—laboratory equipment. A lot of that came from Germany initially, until the Soviet Union was able to manufacture them on their own.
Zierler:
Well, Lee, I think, for my last question, I want to ask you sort of—it’s a question that’s both retrospective and forward looking, and that is: So much of your career was spent within the context of the Cold War, and are you surprised now that, even the Cold War is sort of ancient history, that we’re still armed to the teeth with nuclear weapons? And what do you think the future of nuclear weapons might be in the 21st Century?
Pondrom:
Well, I think, along with everybody else, it would be great to get rid of them. I think everybody feels that.
Zierler:
Except the people who make the decisions, of course. And that’s why we still have them, right?
Pondrom:
Well, you know, they’re getting old. They wear out like anything else. [laugh] You know, interesting that things like the initiator, the source, originally those sources were made out of polonium-beryllium mixtures, where the polonium that emit an alpha particle that would be absorbed by the beryllium and would subsequently emit a neutron. Now, polonium has a finite half-life, in fact, it’s pretty short, so the sources have to be replenished. Now, modern nuclear weapons don’t do it that way.
Zierler:
Yeah.
Pondrom:
Partly for that reason. But there are things that have to—the things require maintenance. They require maintenance.
Zierler:
Yeah.
Pondrom:
I’m not involved in any of that, so I can’t really speak to how it goes, but it would certainly be good for everybody if, after we get rid of the coronavirus—
Zierler:
Next up on the agenda—
Pondrom:
—next stop is nuclear weapons.
Zierler:
I like it, I like it. Well, Lee, it’s been a great pleasure talking with you today. I really appreciate our time together.
Pondrom:
My pleasure. Any time.