Steve Williams

Zierler:

This is David Zierler, oral historian for the American Institute of Physics. It is April 19th, 2021. I'm delighted to be here with Dr. Stephen H. Williams. Steve, it's good to see you. Thank you for joining me this morning.

Williams:

Well, I'm happy to be here. I enjoyed looking at Claudio's [Pellegrini] interview and learned a lot from that.

Zierler:

There you go.

Williams:

I'm ready for anything.

Zierler:

Steve, to start, would you tell me your current or most recent title and institutional affiliation?

Williams:

Oh, well, I was the Assistant Research Director for many years (1988-2010), but then they had to swap around, and I told them I was going to retire in a year (on 6/30/2011). So they put me in charge of the quality assurance, which I didn't enjoy because nobody likes the quality assurance guy.

Zierler:

[laugh]

Williams:

But they were aligning themselves with the DOE's ways of looking at things, so I was their quality assurance manager.

Zierler:

Steve, when did you retire from SLAC?

Williams:

I retired formally June 30th in 2011, and I came back to work the next day part time for another 15 months as a one-person group, actually, that managed some additional monies that were provided to do new research and small projects, called Laboratory Directed Research and Development (LDRD). I had to organize a once a year a proposal review committee and track the progress of everybody during the year. And then I left formally in September of 2012.

Zierler:

And have you been connected with SLAC at all on an informal basis since then?

Williams:

I have a lot of friends at SLAC, and I tried to get back in again. My wife was pretty sick for the last 15 years of her life, and so that's why I retired when I did, which was sooner than I wanted to. I would have liked worked until I was 75, I think. She died about five years ago. Actually, when she died, I had stayed in contact with David Leith. You've probably heard that name, I'm sure.

Zierler:

Of course.

Williams:

And he had hired me three times in the past, so I went to him again. He was retired, actually, at that point, but he put me in contact with the lawyer at SLAC who wanted to have a scientist work part time to evaluate patentable projects and whether or not the physicist/inventor/developed is following all the patent rules and not giving away secrets for free when the university had arranged for a royalty. The scientists liked talking about their work and sometimes they just start talking. I'm very familiar with that. And I had worked for the lawyer before. Hiring was approved but they wouldn't give him any money for me. I would have worked for free, to tell you the truth, because I was alone then. But, in the end, the lawyer retired within the year, so I gave up.

Zierler:

Steve, let's take it all the way back to the beginning. Let's go back to Michigan and I'd like to hear about your parents first. Tell me a little bit about them and where they're from.

Williams:

Well, I had a wonderful family. I was the only boy with three sisters, third born. And my father learned electronics in the Army. He became an electronics/radio expert in the service. When his time was up, he didn't leave the Army, he became a civilian employee in the Army as a radio instructor back in the '30s. So, electronics had always been in his future. He got into electronics early in the Army and spent the rest of his career in it. In particular—after he left the Army—he worked with seismic sensors in the oil fields of Louisiana and Texas. They use a lot of electronics for detecting where the oil is in the ground with explosions that reflect off the layers underneath the ground to tell the scientists where the oil was. He did that and traveled around, but he eventually got married to my mother, who was a nurse, a wonderful person, but I could go on and on about her.

When I was a kid, he worked either at Lear Siegler Avionics at the airport in Grand Rapids, Michigan, or Grinnell’s, an electronics and music store, where he dealt with all the musical electronics, radio and TV and with the Hammond (electric) organ that was a particular kind. Hammond organs generated sound by creating an electric current from rotating a metal tone-wheel near an electromagnetic pickup, and then strengthening the signal with an amplifier to drive a speaker cabinet. The organ was quite popular with churches because with a high power amplifier it could drive large speakers in a large church. It was much cheaper than the popular pipe organs which took up a lot of room and cost a lot. He was quite an expert in that and spent many, many years servicing churches all over Western Michigan.

During the summertime, I traveled with him all over western Michigan to churches to maintain them, which was always fun. I got interested in electronics and science, too. In grade school and high school, I was interested in science in general, electronics in particular, because Dad was a ham radio operator and had his set-up down in the basement. I saw all the vacuum tubes and components. He helped me, first of all, build a cigar box radio, which was a favorite project. Two-tubes and A and B battery which I built to fulfill the Boy Scouts radio merit badge. But later on, in junior high and high school, I wanted to build a Van de Graaff generator which appeared in Scientific American, my favorite magazine after Boy’s Life.

I think in ninth or tenth grade there was a special summer science program for students 14-18. After Sputnik, the government came out with many programs to get kids interested in science. And they had a wonderful summertime program at one school in East Grand Rapids, and I could sign up for math, physics, or chemistry. I hadn't had any chemistry or physics, but I did have math. So, I signed up for math as my first choice, because I knew math. This was in ninth grade. But my second choice was physics. Math was already filled so they put me in physics. I'd been watching a program on TV which you've probably heard about called Continental Classroom. where we learned about physics at 6AM!

Zierler:

No, I've never heard of that. What is Continental Classroom?

Williams:

It was a multiple science program that was held for credit, actually, if you wanted it. I was just fascinated with science. So I would get up at 6:00am in the morning with a notebook—the teacher for the physics section was Harvey White. He was a UC Berkeley professor. I met him later on in life when I went to school at Berkeley. He was a very dry lecturer, but he was talking about science and I loved science. He did many cool experiments (which introduced me to experimental physics). I got up at 6:00am in the morning to take notes. I wasn't even taking physics in school, but that's where my love of physics really started, I think. I watched that for a few years.

Then, I think it was between ninth and tenth grade, the Federal Government announced (nation-wide) summertime classes for physics, math and chemistry. Once again, I asked for math first but physics second, and they said, “Oh, math is already taken up, so we'll put you in physics.” I said, “Ok.” And I spent a wonderful time there. They brought in teachers from the East Coast. Really top-notch teachers, and in particular they helped us build projects. They would set us up an individual personalized project. There was an article in Scientific American on how to build Millikan's oil drop experiment, which measures the charge on a single electron. So I said, “I want to do that.” They said, “Ok.”

They went out to a machine shop and got the custom parts; included was a Plexiglas box which had two plates with a small hole in the center of the top plate. I had a voltage supply (low current) to turn on and off an electric field. I sprayed a lightweight oil above the upper plate. The spray drop would fall through the hole in the plate, sometimes picking up a charge from the spray process. A bright spotlight that comes in from the side, shining through the Plexiglas would illuminate the drops, a little microscope/telescope (that's kind of a medium-distance microscope) was focused on the drop—the microscope had a reticle with lines on it to measure distance at the focal plane—I calibrated the reticle so I could measure the speed. The upper plate was positive so the drops would fall through with the electric field off and when the voltage was turned on they would turn around if they had become ionized while traveling under the influence of the electric field.

I turned the voltage on and off, and for an hour you could have a little drop which became ionized because of the spraying of the oil. It would travel up and down, and you could measure the speed of it as it drifted through the air with a stopwatch. The drop was slowed down by molecular motion, and the article in Scientific American gave me the formulas for calculating exactly what the charge might be based on the observed speed. That was a project that I enjoyed there, and then I kept going with it for several years. When I was a senior in high school, I entered it into the local science fair and won first place. So, I think my dad helped me with all these things because he had all this stuff in the garage to fix these things.

Later in high school— in Scientific American there was an article about building an electron accelerator using a refrigerator pump for a vacuum, instructions on building an oil diffusion high vacuum pump, and a Van de Graaff generator (about 100-200 kilovolts). Another student at the summer program had built the Van de Graff generator so was able to get that. I was able to get a 12-inch spark from the generator. Fortunately, I never got to the point of generating X-rays. A year after the article in Sci Am a second article came out that said they should have discussed shielding because it was a fairly strong source of radiation. I am glad I failed.

Then I started thinking about college. I had pretty good grades in school. I started seriously studying physics in college. I think it was curious that seven years later I was a student working at the most powerful linear accelerator ever built!

Zierler:

Did you want to stay close to home specifically?

Williams:

No. I wanted the best college I could get into, and the University of Michigan was my favorite. Two of my sisters had already gone there, and so that was the one I was targeting. They had a good physics program anyway. Still do. But after I graduated from high school, I didn't have enough money to go. My parents didn't have the money to go either. But we had a really good college in town, Grand Rapids Junior College, and it had a great physics course there. That physics teacher was great for me. I asked him at one point during the year: “I don't know whether I should become an engineer because you make money at engineering, or I should become a physicist but I don't know if you make any money doing that?”

Zierler:

[laugh]

Williams:

And he said to me, “Do physics. You can get an engineering job with a physics degree.” So I said, “Ok. Physics it is!” I was working in a chemistry lab for a family friend who did electroplating for the auto parts business. I helped the chemist to analyze the tanks of plating chemicals. I worked full time during the summertime for several years there. So, I managed to save some money and I applied for a $500 grant from a local foundation place which I got (first place in the science fair helped). So, I began to finagle my way financially through college quite effectively. Let me stop here and say this was only the beginning of my success in finding money to take me into the next phase of my career. The next was the NDEA loans of the ‘60s: terms were 3% interest that didn’t start until one year after you left college. I stayed in college all the way to my PhD. With an NDEA loan I was able to go to the U of Michigan for my final three years.

Even there I had a meal job here and there, working at a restaurant from 5:00 to 7:00 for just the meal. I got to eat at 7:00 after that. It was a small restaurant. It was one of these just grab a bite to eat and go. It was like a counter that went front to back. No tables, just a long U shaped seating arrangement. All the stools went around the counter. I was running up and down the middle taking orders and taking them back to the kitchen and bringing food out. Two regular customers were nuclear engineering students up at what was called north campus at Michigan, where the nuclear engineering department was located. One day they asked me what I was studying. I told them physics. “Oh, really? You ought to come up to north campus and maybe we can find some work for you to help us out with our experiments.” So I did that. I dumped the meal job and didn’t need any more NDEA loans (and no interest or payments for 8 more years!!) and I started going to North Campus on the bus every afternoon and working for real money. And that went on for a couple of years, including the summertime.

So, I was having no trouble funding my undergraduate education. I worked on more cool stuff: lasers and power supplies to drive lasers, things like that. It was a lot of fun. I loved physics and I had all these opportunities to get into it, and it just inspired me. And then, of course, when it came to graduate school, I got my B.S. in '64, I applied to five graduate schools and got accepted to every one; but Berkeley was the last one and the most desired. Because, to me, it was the era of the Bevatron at Berkeley, which was a famous accelerator. Particle physics: my goal!!

Zierler:

Right.

Williams:

That was what I wanted to study. I had been watching the Continental Classroom on atomic physics and that's what I want to study!

Zierler:

Steve, did you ever give thought to staying at Michigan for graduate school?

Williams:

No. Actually, it would've been a great physics department, too, but I don't know, one of my sisters had already moved to California to the Bay Area. Her husband was a PhD student in engineering mechanics, and ultimately worked for Lockheed. He went to Stanford in graduate school. So they were already out there. I had a connection to California. California, to me, was like the dream place to live. Also, Berkeley was my number one preferred graduate school.

Zierler:

Yeah. Steve, what was your sense in the Michigan Department of Physics, what was the most exciting research going on at that point?

Williams:

I wasn't all that aware of the research that was happening there, so I didn't even look into it since I was already hell bent to go to Berkeley. So, I just finished my courses and applied to those schools, and Berkeley finally was the last to accept me, but that was it. I'm gone.

Zierler:

Was there any professor at Michigan who you considered a mentor?

Williams:

Not really. I did work for Martin Perl's class at one point. I had various jobs during that time before I got the nuclear engineering job. But I was setting up classroom labs for Martin Perl, who was professor of physics at the time. I met him again later at SLAC. I was interested in atomic physics and nuclear physics, and basically the fundamental building blocks of nature. Particle physics is what I really was focusing on. Berkeley had an accelerator after all, the Bevatron. They actually had several machines. I actually worked on the Cyclotron. I never worked on the Bevatron. It was a good choice for me, as I will explain as we go on. So, I went off to Berkeley and arrived at the beginning of the free-speech movement. Oh, what an awakening for me! I came from the Midwest. But it was quite a year—several years, actually—because I started Berkeley during the free-speech movement, and I left right after People's Park. Did you know about People's Park?

Zierler:

I've heard of it, yeah.

Williams:

That was a famous one. Then I moved down to Menlo Park (Stanford). But I had a fabulous five years living in Berkeley. It was an exciting campus and great physics was there. I started out, of course, taking courses and passed my preliminary exam, which you have to do before you can even start your research. But I met, even before I started the first year—I needed a job, because I had enough money saved up for most of the year, but I needed a little bit more. So, I applied for a readership for a Physics 10 course, which is physics for non-physicists—you know, young ladies and young men who had to take a science course. There was a head teaching assistant who was in charge of hiring the readers (who graded the students' homework), and he looked through the names of all the people on his list. There were 10 of us that he needed to hire, because there were a thousand students in the two classes, and they had assignments that had to be graded every week or two. The head TA looked at the names, and mine was the only WASP-ish normal American name. He knew he had to have somebody who spoke English quite well as the head reader. So, for that reason alone, he selected me and called me up and said, “Do you want to be the head reader?” I did. I held office hours for the young ladies (and men) to come in and complain about the reader marking their answer wrong. That was my first opportunity at management. Never considered myself a manager until later in life, which I'll tell you more about later.

Zierler:

[laugh]

Williams:

But that relationship with—Leon Kaufman was his name—led me to an advisor up at the lab (LBL) where Leon was working on his PhD using the Cyclotron. Later the relationship with Leon led me to other jobs and which I will tell you about a little bit later. But he and I got along quite well until we didn't get along well (years later). I ultimately worked for him for a while, and I found him to be quite rude when he was unhappy, and just thought it was sort of unfair to my earnest effort. I had the head reader position for the first year at Berkeley, which gave me plenty of money. I was working 35 hours a week and the office was right on campus, so I had plenty of money to get through that first year. He then made arrangements for me to be a teaching assistant during the summertime, so I didn't have to go back to Michigan if I ran out of money. Then he recommended me to be the head TA for the second year, so my life was golden. The salary for a TA was really quite substantial compared to all my previous budgeted numbers. In my third year I became a student of Victor Perez-Mendez, who was my advisor for my PhD thesis. Again, my salary went up.

Zierler:

Steve, what was Perez-Mendez working on at the time you connected with him?

Williams:

He had developed magneto-strictive readout wire spark chambers, which I fell in love with. They're really a lot of fun to work with. It involved computers, one of my favorite things to deal with. These spark chambers were intrinsically electronic when compared to bubble chambers which require humans to scan big photos, one by one. But the magneto-strictive wire spark chambers had a totally electron readout. They were read it into a computer, put it on tape, and then you'll have all this data, so it was very attractive—because computers and electronics and physics were what I wanted to do.

Zierler:

And data for what? What kind of relevance did this have for explorations in particle physics at this point?

Williams:

The chambers measured the tracks of low-energy pions that were produced in the helium target of Leon’s thesis experiment. We used them for pion-helium collisions at 0.35 GeV. There was a lot of interest in the physics of pion interactions with helium. That wasn't my thesis experiment, but that was Leon Kaufman's thesis experiment, so I was working with him, learning about the chambers and eventually using my expertise at the SLAC experiment. After he graduated, he went to a science group, Bell Labs, that had research offices in Washington, DC, where he would be a science advisor to people in Congress and in government in general. But he hated it. He wanted to get back to the laboratory. He eventually returned to work with Victor again as an adjunct professor of Physics in the Nuclear Medicine department at the UCSF medical center. More on that later.

Zierler:

Sure.

Williams:

Perez-Mendez had developed the magneto-strictive wire chambers and he was looking for anybody who wanted to use them. In particular, he had met David Leith at SLAC at Stanford. I didn't even know that Stanford had a high energy physics program when I went to Berkeley. Little did I know that I would eventually spend most of my career there.

Zierler:

[laugh]

Williams:

Because Berkeley was the mecca for particle physics—I never thought about applying to Stanford. It was a private school, after all. But Victor had these spark chambers. He was building them quite large. David Leith was doing an experiment with photo production using the linear accelerator at SLAC to produce secondary high energy photons (Multi Gev gamma rays). The gamma ray photons could be directed at various targets to see what happened inside the nuclear matter. The gamma rays created the rho meson within a various size nucleus from hydrogen all the way up at lead. We had targets of various nuclei whereas the rho passes through the nuclear material before leaving the nucleus where it may be absorbed. It didn't travel too many nucleus diameters, so you could determine the cross section between a rho meson after it was produced in the nuclear matter. By looking at it for various nuclei, you could determine the cross section for rho mesons in nuclear matter. That was my thesis experiment at SLAC.

But Perez-Mendez gave me a great introduction at LBL, and I was the next in line of graduate students of his to go down to SLAC. And he introduced me to David Leith and Rudy Larsen, and many really nice people. So I spent several years commuting down there. I was single, after all, and I would stay in motels and the university would pick up the bill. So, I commuted to SLAC for several years.

Zierler:

Steve, just to clarify, was your research, was it not possible to conduct this at Berkeley lab? Why go all the way to Palo Alto for this?

Williams:

It was because we needed high energy photons (gamma rays) at 5, 7, and 9 GeV. Nothing like that was available in Berkeley. The Bevatron and Cyclotron were proton accelerators but could produce secondary beams of pions and protons in the sub-gev to several Gev energies but not photons. SLAC, on the other hand, was capable of accelerating electrons up to 20 Gev/c. It could also create and then accelerate positrons which upon entering a liquid hydrogen target would annihilate with stationary electrons to produce a secondary monochromatic photon beam needed for my experiment: photoproduction of rho mesons. I went to SLAC for my first meeting in 1967 with the group as a collaborator and spent the next three years working on data collection and analysis. Ultimately I became a postdoc at SLAC after David Leith asked me to join the group.

Zierler:

When did you have enough material in your research to defend the thesis?

Williams:

That's a story. We collected and analyzed the data by early 1969. I passed my qualifying exam (thesis defense) in May of 1969, and David had already offered me the job which I started July 1st, but I hadn't written my thesis at that point. I had an outline, but I hadn't written it. David and I had some issues with the measurements that we'd made that we were uncomfortable with needed further analysis. So, I kept studying for three more years after I became a postdoc at SLAC, finished my thesis, had it signed and turned in in 1972. (Attended my graduation, my parents came from Michigan… the whole nine yards.) Then my degree was granted, and I was legit. SLAC never did that again because they said you have to make sure you have the thesis turned in and the degree is official before you're hired as a postdoc. But I lasted the three years, and I finally submitted my thesis and had it signed off by the committee.

Zierler:

Who besides Perez-Mendez was on your committee?

Williams:

I can't remember their names at this point. That was a Berkeley committee, of course. There was a nuclear engineering professor and Dr. Selig Kaplan. I don't remember that. I'd have to go back and look at my thesis, which should be lying around here someplace. But I could read off the names, but I don't remember that.

Zierler:

Steve, to zoom out a little bit, this, of course, is such an exciting time generally in experimental particle physics.

Williams:

Yes

Zierler:

How did this research relate to some of the broader questions that were being raised at this point?

Williams:

Well, there were a lot of questions being raised, but the rho meson was just a particle which people wanted to understand better. After all, it was fairly newly discovered, but you could produce them with SLAC’s clever photon beams. The accelerator physicists came up with this unique idea of having them produced and scattered inside a nucleus and then increasing the size of the nucleus. So that was a way of determining the cross sections. SLAC, of course, was involved with many other things. It seemed kind of crazy to take an electron-photon machine and turn it into a pion machine, but that's what happened at various times.

Of course, while we were looking at gamma ray collisions with nuclear matter, a large part of the lab was developing SPEAR, where electrons were being collided with positrons. You’ve heard of the November Revolution where these collisions rates went up by 100-fold at a narrow region around 3.1 Gev/c in the center of mass. The J-Psi particle was born. Sam Ting had also quietly observed the psi resonance at the Brookhaven machine in a more subtle way. But he didn’t announce it six months earlier, being a careful experimentalist. When he came out to SLAC to review our research it was a week or two after the SPEAR people had seen this incredible and dramatic increase in rate in e⁺e^- collisions. When they announced their results at the meeting, Ting said he had seen the Psi six months earlier but did not announce it. In the end the Nobel was shared. Exciting stuff at SLAC and BNL.

Our group did other things at the lab. Later on we collided—I think it was high-energy pions with hydrogen and maybe even deuterium at times. But I lost track of a lot of those things in those intervening years. SLAC started building the SLC/SLD collider, an electron-positron beam collider and Z physics particle detector. Somewhere in there (1977-78) I left SLAC because my friend, Leon Kaufman, was out of the government work and into UC Med Center in San Francisco doing medical research. He interested me in becoming an assistant professor there to apply my knowledge of detectors to imaging for cancer patients.

Zierler:

Steve, at the time, what imaging was available before this research got really started?

Williams:

X-rays and radioactively labeled organic chemicals were being used to identify tumors. Leon got interested in MRI which started out years earlier by localizing the hydrogen atom from water and fat in the human body by flipping the nucleus of hydrogen and measuring the intensity of the radio signals (15 MHz +-). The signal was an indication of how tightly bound the hydrogen was in the muscle tissue, fat and bone. Hydrogen in bone gave off very little because it was tightly bound. Hydrogen in fat was loosely bound so the signal was large and bright. It took a long time to relax. Hydrogen was also loosely bound in blood so it should give a large signal, but it was moving rapidly and exited the vessel before the echo was detected. Instead of a large signal you would see nothing. So, three dimensional maps of hydrogen flips measured morphology similar to X-rays and cat scans but the contrast was intrinsically brighter and revealed subtle problems like tumors and other damage. It was 3-dimensional morphology which did not require surgery to see problems. Abnormal morphology could be easily seen.

I started working on head coils and software at UCSF/Nuclear Medicine. I was working on that plus some other interesting things with positron decay, injecting people with positrons which would then annihilate inside the brain or the body somewhere and it would produce back-to-back gamma rays. So they were seen exiting in opposite directions on either side. By locating all the back-to-back pairs (straight lines) all the directions and displacement of all these things, and then figure out where the densest chemical deposits are located and try to map out a tumor which was labeled with some organic chemical that had positron annihilation as part of its decay.

I worked on that a little bit, although it wasn't my primary job. I was primarily working with the detection of gamma rays in germanium. Leon had worked with germanium crystal companies to produce a grid—a small, pixelated camera about the size of your palm. It could be located over the thyroid gland in the neck, for instance. The thyroid was injected with the gamma ray emitters, and the organic chemical would attract itself to the tumor location and then identify the size and shape of the tumor. This image was the image of the tumor structure. That was Leon’s claim to fame at the time. I don't know that it's ever been used again. Wire chambers were used for imaging X-rays. I worked for him for a year. It was interesting work. I also taught. That's when I learned I didn't like teaching.

Zierler:

[laugh]

Williams:

I was teaching med techs who didn't really want to take physics but had to, and teaching was a time-consuming thing for me because I found the first year you teach—I would teach a three-hour class twice a week -- it took me, I think, three hours for every one hour I spent in class preparing for it because I'd have to bone up on the subject material. I'm sure that if I stayed with it for five years, I would just grab a folder out of my file cabinet and go off to class and so, “Ok, here's what we're talking about today.” But I didn't last that long there. I just didn't enjoy it as much as I enjoyed SLAC.

Zierler:

Was there something satisfying about applying your physics expertise to advance human health?

Williams:

Yes. At a cocktail party everybody knows somebody who has had an MRI, and how wonderful it is. But they go silent when you talk about particle physics. To me, it ended up being a curiosity, but I didn't really like working for Leon, to tell you the truth. As a colleague—as graduate students we were good together—but he could be quite a mean son of a gun at times, and I thought he was somewhat irrational at times. He was a South American hot-headed guy. But he was an inspiring person also. Very smart. But I decided I didn't like working for him, and I called up David Leith and said, “Can I come back?” He said, “Well, I'll see what I can do.” And he brought me back into the same group, and I was doing the same stuff that I did before. Happy.

Zierler:

Steve, I wonder if you could explain the overall structure of where group B fits in with the overall research happening at SLAC at that point?

Williams:

SLAC was originally built with two large End Stations where “A” had large electron scattering spectrometers for 20 GeV/c electrons and two lower energies. End Station “B” which housed ad hoc experiments, like my thesis experiment and a small hydrogen bubble chamber. The early experiments in the straight-ahead C line were used with large optical spark chambers with cameras and a larger bubble chamber, also used cameras. The beam came straight out of the Linac when they wanted to get higher energy electrons without having to bend them very much, because they radiate when you bend them in a magnetic field. Eventually with the success of synchrotron radiation experiments at SSRL the C line was converted to a wiggler beam for electrons which would produce intense low energy photon beams for chemical experiments. Today, the lab, on site, is primarily a low-energy physics lab where they use X-rays to study chemistry. But SLAC supports high energy physics efforts with staff and experimental equipment in facilities at other labs around the world and in space.

That's where they built various dedicated spectrometers that would run at 20 GeV. And would scatter electrons off various targets of hydrogen, helium, and heavier nucleons to study the behavior of electrons in the vicinity of a nucleus at high energies. But when I started at SLAC, they already had been developing—they would convert the electrons to positrons by slamming them into a target about a third of the way down the machine, and then reverse the phase of the machine for the rest of the time and accelerate positrons through the end of the machine. SLAC became a source of high energy photons (multi MEV gammas).

That was important for my thesis experiment which used the accelerated positrons into liquid hydrogen where the positrons would annihilate with stationary electrons which would produce gamma-rays at fairly high energies if you selected the direction carefully. So that's why I could have secondary photon beams at 5,7, and 9 Gev into various targets with the different nuclei sizes from aluminum, copper, lead. That's how I studied with photons-nucleus interactions. The electron beam became a positron beam and became a monochromatic Gamma-ray beam, but with very high-energy photons. It was really a unique opportunity in the world at that time, so SLAC was the place to be for doing that kind of physics. Other experiments used the primary electron to create secondary pion beams for another experiment, doing pion interaction scatterings.

Later on they started building the SPEAR electron-positron collider by using electrons and positrons from the linac to fill an e⁺e^- storage ring (circulating in opposite directions) that discovered the Psi particle.There was this giant resonance at 3.1 GeV in the electron-positron collisions that created a huge increase in data rate. It was a total surprise. Once the storage ring was filled with e⁺e^- colliding beams the energy could be increased step by step with an RF system in the ring that boosted the e⁺ and e^- energies in steps. The physicists had colliding beams in the storage rings and they were just scanning the energy of the storage ring step by step, increasing the energy and looking for the reactions around the interaction regions, which were 90 degrees to the ring direction. But when they narrowed down the step, it was such a narrow resonance it went up many orders of magnitude right at 3.1 GeV. It was a Nobel Prize, ultimately, Burt Richter and Sam Ting—but I wasn't involved with that. It was just fun to watch.

Zierler:

Was Pief Panofsky around? Did you have an opportunity to interact with him?

Williams:

A little bit. He was, of course, the director most of the early years that I spent there before Burt Richter took over. I didn't have a lot of interaction. I interacted with David Leith primarily. Do you know David Leith? Do you know the name?

Zierler:

Of course.

Williams:

The personality?

Zierler:

I'd like to hear more about that. I haven't heard that much about him.

Williams:

He died in early 2020. It was hard for me to believe. He was a huge influence on my life. He went too soon.

I got along terrifically with him. He's a big guy, 6 foot 4, at least, 5 maybe. And I'm already 6 feet, so I was always impressed by just his stature. Scottish, and just a great communicator, but he had a lot of biases, and he always thought he was right—many times he was! As well as I was getting along with him, he was almost like a father to me. But the other professors I think had differing opinions—these are all big ego people, as you know. I think they didn't like his style at times. With me he was always very gentlemanly. After all, I was working for him. I wanted to do what he wanted me to do. We had an argument once when I didn’t agree with him, and he knew I was unhappy with something that he had done or said. But he turned to me and said, "Steve, are you ok?" in the gentlest way. I wasn't going to argue with him because he was a big guy, and he was the group leader. Nevertheless, he treated me with kid gloves where he didn't treat other people like that in competing groups. David and I weren’t competing. It seemed wise of me to just let it go.

Zierler:

Competing within SLAC or beyond SLAC, do you mean?

Williams:

Within SLAC.

Zierler:

Uh-huh.

Williams:

Well, the group leaders—there were eight or so groups within SLAC with professors on a par with David that had their own projects and were pursuing various physics goals which did or didn't compete with him in terms of money.

Zierler:

What was the overall research mission, would you say, of group B during your postdoc years?

Williams:

Well, it started out with my thesis experiment and my introduction to it when I was a Berkeley student, and that was photoproduction of rho mesons. But then later on we actually did some pion physics, fairly high-energy pion physics in then station B. And, of course, we eventually joined the detector group building components of the 90 GeV/c electron-positron SLAC collider. In particular, there was a Cherenkov technique that came to David Leith, [with] SLD as being just right for those kinds of energies in order to discern the mass of the particle whose momentum was determined by the inner tracking detector. The Cherenkov detector then established the velocity and therefore identified the mass of the particle.

Zierler:

What does that mean, Cherenkov technique?

Williams:

In the interaction of the intense, high-energy electron and positron beams (at 90 gev) at a focus point in the center of the vacuum pipe inside the detector, a Z particle is created and immediately decays into many lower energy particles—electrons, pions, muons, protons—laterally. The charged particles traveling outwardly transverse to the solenoid’s magnetic field bend in an arc/circle determined by their momentum (mass times velocity). So, the inner tracking chamber they first encounter measures their momentum and direction. A pion and an electron traveling in a magnetic field cannot be distinguished in a tracker if they have the same momentum.

Another method to distinguish two charged particles of different mass with the same momentum is needed. This can be accomplished because a charged particle traveling through an optical medium faster than the speed of light in that medium emits light photons in a cone with an angle related to the particle's velocity. This is much like the cone of sound emitted by a jet plane traveling through air faster than the speed of sound. The SLD Cherenkov technique utilizes a second detector outside the tracking chamber with a photosensitive gas that releases an electron when a Cherenkov photon kicks it out in a drift chamber that drifts the photoelectron to a detector where its position can be measured and related spatially to the charged particle arc/circle seen in the tracking chamber. By relating the location of the Cherenkov photoelectrons (there will typically several from one track) to the particle track you can tell whether the particle emitted a large cone or a small cone of photons and hence probability of its mass being large or small. Pions, electrons, muons and protons can be separated by looking at the cone of photons.

I worked on that before and after my one-year stint at UCSF. David brought me back and I was right back in the middle of things. However, this is where my life changed a little bit. Because I was a little more mature at that time, and during my first stint at SLAC—there are three stints—at my first stint I was primarily working down in the end station with these magneto-strictive readouts and all the detectors that we were using for tracking particles into and out of the magnets so we could determine the momentum. But then, when I came back the second time, the Cherenkov detector that was being developed before I left, was still being developed a year later, for the purposes of the SLD, which was the large detector in the interaction region of the collider. I came back the first time in 1979, and David hired a few people to work on the techniques involved with Cherenkov counters for SLD. These were experimental at this point, being developed towards the detector which was years away. David scared me at one point when we were going to the meetings and discussing with the engineers and technicians and other physicists what projects we were going to do this week. He said, “Steve, I have to go to a meeting. Would you take over the meeting today?” And I said to myself, “What? Me manage? Oh, I don't like this.” But to him I said “OK”.

Zierler:

[laugh]

Williams:

But I knew what I was talking about. He just asked me to do what he was doing, and I knew how he was doing it, so I started managing the meetings. Before you knew it, I was managing. I didn't like it at first because, first of all, I was managing, which meant I gave other people the fun projects to do down in the research yard: the electronics and the gas systems and the spark chambers, computers and other equipment. But I got used to it and it made a big difference for the rest of my career, to tell you the truth.

David gave me a lot of respect in it, and I was, frankly, rather good at it. That's when I learned something about what management is. Management is simple. It's getting things done through others. And at first, I was champing at the bit, I wanted to do the experiment myself; I didn't want to give it to someone else. But then I said, these guys are pretty good. They've done a good job on it, and I let them do things. It's nice to see productivity when all you've done is given an instruction and they come back with answers. I said, I like this management thing!

Zierler:

It also requires a level of trust, that the people working for you can do what you want them to do.

Williams:

Yes. I had only trusted myself before, but David kind of forced me into a position where I was able to delegate and get feedback.

Zierler:

Was your sense that David was specifically trying to teach you this lesson when he abruptly put this responsibility on you?

Williams:

Never occurred to me. He just asked me a simple thing, “Can you run the meeting now?” I've been in these meetings for years so of course I could run it, but, whoa, do I want to be in charge? No, I want to give myself projects. I don't want to give anybody else projects.

Zierler:

And this was not a one-time responsibility? You sensed that he wanted you to do this from now on?

Williams:

Well, he was managing me. And I liked it. I left SLAC the second time to become a director of engineering at a medical imaging company, interfacing with Leon Kaufman at the UCSF lab across the street from Diasonics. Basically, I was doing technology transfer out of the university lab into the company, which was right across the street from the lab I was working in during my previous venture to UCSF. So I became a director of engineering. Who knew? And I'm dealing with this corporate structure, which was very interesting and paid well. But, while it was interesting, after three years experience, my curiosity was satisfied. I didn't really like it as much as I liked SLAC. So back I went, happily.

Zierler:

Now, during your second stint at SLAC, how far developed was SLD by the mid-1980s? What had it achieved and what was remaining to be done on the SLD?

Williams:

It was going together but it wasn't yet operating. The SLC arc/tunnels were being dug and beamlines being designed, and magnets ordered, etc. Group B and outside labs were designing and building many of the detector components for the full-size device, which must have been 9 feet in diameter, fitting around the 4-foot diameter wire chambers in the middle of the SLD detector where the e⁺e^- beams collided. But several other universities were brought in to help contribute various parts. That proceeded without me because I chose to go off and work in industry for real money. I did get quite a significant increase when I worked in industry. Diasonics was the company that was marketing the MRI business.

Zierler:

Was that a startup at that point, Diasonics, or it had already existed?

Williams:

No. Al Waxman started Diasonics with ultrasonic medical equipment which he had designed and funded his new divisions. He met Kaufman and started putting together the MRI division and later added a kidney stone division. Diasonics had three divisions. The one in South San Francisco was the MRI division. The others were in the east bay and Colorado as I recall. Working in industry was a lot of fun. Trade shows—well, you've never been to a trade show 'til you've been to McCormick Place in Chicago. This huge display hall which was filled with 20 or 30 semis filled with portable medical equipment. That was a small part of the show. You couldn't even see the semis, there were so many other things in there. There were booths covered with carpet because it looked so nice. The salesmen were running around after hours bringing their fellow salesmen in other companies into their booths, because they couldn't do it during the daytime. It was quite a show for me to participate in that.

But after three years of it—and I wasn't working for Leon directly. I was really hired because I was a friend of Leon's and had worked in his lab, which was developing new technology. Now they needed to transfer it into the manufacturing, sales, shipping and operating phase. So, it was a neat experience for me to learn about corporate finance and manufacturing, quality control, and the like, production-line, marketing, sales type of situation. I wasn't developing new things, but we were taking the science developed in the lab and turning it into a product. I helped explain the physics of MRI to engineers that previously worked with CAT scanners.

Zierler:

Were you operating more as a physicist, would you say, or as a business manager?

Williams:

No. I was an engineering manager but frequently explained how the equipment worked to engineers and even finance people.

Zierler:

Yeah.

Williams:

It was a highly technical job because I had to communicate with the UCSF people—scientists and engineers. They didn’t know about manufacturing in quantity. I was learning about all that and interpreting their scientific successes to the manufacturing people in Diasonics. They had only to keep two machines working in Leon’s lab. They did everything that Leon needed for his machine, which was a few feet away from his office. His MRI wasn’t in a hospital or clinic so they would tweak it up anytime. The engineers there didn’t always think about how to manage the service for 30 machines, 60 machines, or hundreds of machines that Diasonics ultimately sold. The Diasonics service engineers didn't work for me, but they came to me when they had problems and they wanted me to get answers out of the university.

The engineer they had at UCSF who had done all these things at the knee of Leon Kaufman wasn't a good communicator, and he didn't document things very well in the lab in the way that manufacturing and service needed it, so the company engineers had to redo and document everything themselves. In the real world of manufacturing, with hundreds of machines out there, the company provided service engineers to each machine to keep them running. It was interesting. I enjoyed working with all those people, and they seemed to enjoy me. But after three years, I said, you know, I got it. I see what this is. I was making good money. But I had the same wife, same car, same house. I didn't need the money. I missed SLAC. So, I called up David Leith again. He said, “Oh, gee. The lab's really in turmoil right now but I'll see what I can do.” Charlie Prescott, a professor at SLAC I had known for many years, had replaced Richard Taylor (I think) as the Research Director. Charlie Prescott is a really soft-spoken, cool guy. He is a smart guy and very considerate of people.

Zierler:

Had you worked with him previously at SLAC?

Williams:

Not directly. Just talked to him and about things in the lab. He had a different group—Group A, I had started in Group B. I don't think we ever collaborated with him. Panofsky had retired and Burt Richter—Nobel Prize winner—stepped in as the director at that point. He and Charlie were quite close. Richter hired Charlie Prescott to become Research Director. This was when I was still in Diasonics. He had been Research Director for a year or so when I called up David and said, “Can I come back, because I'm bored here?” I really liked SLAC better. It was a much better environment for me. He said, “Well, I'll have to see.” He talked to Richter and they talked to Charlie Prescott. Charlie Prescott was concerned and unhappy about the interruptions that a research director faces daily. He thought: “Well, if I get an assistant then I can have him handle the interruptions and I can get back to the physics”, which made sense to him and made sense to me, to tell you the truth, because I'm a service-oriented, people-oriented manager.

After all these years, I've really learned to delegate and excite people about doing things and wait for them to produce the goods and get them to me. He hired me as the lab’s first assistant research director at SLAC. But he made two mistakes. The directorate was on the third floor of the Central Lab. He put me down one floor and over one building. That was the closest he could find an office. It was over by the library. It was a nice enough office, but keep in mind, he also gave me 50 percent of my time that I could do on research. So, I was back at the collider working on their Cherenkov imaging detectors. I took full advantage of the 50 percent to work on research. He would call me to his office, occasionally to give me an assignment. But he didn't use me very much. So, after another year or so he said, “I'm still tired of this. I'm quitting. I don't want to do this anymore,” at which point Burton Richter asked David Leith to be Research Director. David actually came to me and said, “Burt asked me to be the research director. Is that ok with you?” And I said, “Fantastic.” [laugh]

Zierler:

[laugh]

Williams:

I mean, it was just a piece of cake. Leith and I worked another nine years there before he stepped down. About that time Burton Richter decided to step down and named Jonathan Dorfan as the SLAC Director. David decided then to step down after his fairly long stint as Research Director. Jonathan asked me to serve as Acting Research Director for 6 months. While he sought to recruit another person as the Research Director at which time I would resume my assistant role. I said yes. That six months was the best year and a half at SLAC. It took him a while to recruit Persis Drell from Cornell as the new Research Director. I enjoyed “acting” thoroughly.

Zierler:

Steve, what were some of your responsibilities in this role?

Williams:

My primary job was to interface between Jonathan, the group leaders and Charlotte Chang, (David’s financial planner and then mine). She had been working with David and me for years, so she knew how to talk with the Group Leaders about their budgets and projects. I worked closely with Jonathan especially when it came to giving progress reports in management meetings with group leaders. Jonathan and I got along great. He once bragged about me to a visitor about me being a “Win, Win” manager in dealing with people. I was surprised and delighted.

I was well known in the lab. The group leaders had known me for a long time and treated me well. I, of course, consulted with Jonathan often also. That's why all these admins recommended you talk to me, because I was always talking to them about anything that David didn't want to bother with. I can't remember.

Zierler:

But it was mostly administrative responsibilities? Were you operating at all as a physicist in this role?

Williams:

No. I was just managing the business of the Research Division. The rest of the story is that Charlie Prescott didn't really know how to use me. He would call me up once in a while, or send me an email, and then I'd go see him a time or two for the week. Then I'd go back to my research, on which I probably spent more than 50 percent of my time, which was all right with me. But David Leith immediately put an office on the third floor two doors away from his, so I moved off the second floor and that was where my life changed.

I wasn’t able to do much research after that because David—I was two doors away would just come over to me any time of the day or night and dump something on my desk, and I would take care of it for him. He was quite good at that. Unlike Charlie Prescott I liked the challenges of interruptions. David wasn't that popular as a research director with the group leaders, though, because he had a huge ego. Never worked negatively for me because he and I had a kind of relationship where I really enjoyed working with him and he was never harsh with me, and I had a lot of respect for him. But other people didn't like him because they were competing for money as group leaders. And now he was the research director. So if he didn't like their research, I think he probably wasn't as good to them as they thought he should be.

One fun thing was when David asked me to give him a personnel review, as he would do reviews once a year with me. He took those seriously, and he, of course, always reviewed me quite favorably. But then he said, “Steve, I want you to review me.” So he had me come into his office. I kind of squirmed in my seat for a while, but I finally got brave and I said, “David, you're a micromanager. You need to learn to let loose and make decisions and just give the money to someone and trust that they'll do good things with it based on your agreed goal,” or something like that. He said, “I know that.” He knew he was a micromanager. It was in his blood. I don't know. I don't think he could ever change.

Anyway, so when Jonathan Dorfan was going to come upstairs, he knew there wasn't any room for him at that level, so he went back to managing his group. He was five years older than me, but he was well along in his career. Jonathan came to me one day seven months after David had retired and Dorfan had taken over, and said, “Steve, can you take over the research division tomorrow?” I said, “Ok.” I mean, I had been experienced with 11 of years of being under a research director, so I knew how it worked.

Zierler:

Yeah.

Williams:

I worked very well with the financial person.

Zierler:

This was not quite the existential leap as the first time David Leith asked you to run the meeting?

Williams:

Right, right, right. Yeah. No, I was heavily into management at that point, and enjoyed it, enjoyed the heck out of it. And I got along with everybody, unlike David who—everybody had their grudges against David for some reason or other. So, I was a researcher. Jonathan told me, “This will be for six months until they can hire someone else.” A year and a half later... [laugh]

Zierler:

Right. Famous last words.

Williams:

It was the most fun year and a half I spent at SLAC. And I got a lot of credit from people, because I was an easy to get along with. The finance manager was superb. She would go out and talk to the group leaders about what they needed. I, of course, talked to Jonathan about how money was disbursed. But that was the greatest year and half of my life at SLAC.

Zierler:

Steve, beyond SLAC, were you dealing with anybody in the DOE at this point? Would that rise to your level?

Williams:

Oh, certainly one of my interactions—I should have said this earlier—is with the DOE, the local office, typically. I attended only one meeting in Washington, D.C. But there were issues with the DOE all the time where I had to communicate to the DOE on site staff about things that were required, and DOE had things that they needed to get done. Unfortunately, I don't remember a lot of those things. I remember all the fun times, which I'll tell you more about. So, Jonathan found Persis Drell. You know Persis Drell?

Zierler:

Of course.

Williams:

She was hired out of Cornell. I think she was an assistant to the director there. But she was hired as the Research Director. I didn't know her at all. I knew her father, of course, Sid Drell, and I'd heard about her and all that. She was a kid growing up at SLAC—around SLAC, anyway. So, at that time, I acknowledged that she was going to come in a couple of months and she would be my new boss, and that was fine with me. And she was looking forward to it; I was looking forward to it. But during those two months, a headhunter for Jefferson Lab in Newport News, VA, was looking for a research director and they got my name from somebody. So, they were going to set me up for an interview at Jefferson Lab. I forgot the director’s name. I said I was interested. It would've been a big move for me to the East Coast and all that, but houses were cheaper than California. But I already had a house.

So when Persis came, I told her, “Look, I will be interviewing for the research director job at Jefferson Lab.” And she said, “Oh, that's OK.” So, we started working together along with the finance manager, Charlotte Chang. The three of us were like the new triumvirate or something. We all got along so well that when JLAB finally called me after two months and set an appointment to interview. But the headhunter called me up and said, “Oh, they gotta call it off because there's some problem at Jefferson Lab and the director doesn't want you to come in at this point, but we'll call you up later.”

So I canceled my airplane tickets and all that and said, ok, I'm having fun here with Persis and Charlotte, and everybody was just so compatible at that point. I got a nice raise at that point, maybe partly because I was threatening to leave. Persis and I and Charlotte were just so synergistic in all of our management practices that we were a fine threesome. A couple of months later they called me up from Jefferson Lab and said, “Ok. He's ready to have you come.” I said, “No, not coming. I'm not interested anymore.” Some things are worth more than money and that is just a fantastic working relationship that I had with Persis and with Charlotte. And I was very happy to remain at SLAC.

Zierler:

Steve, what were some of the outcomes of this successful triumvirate, this relationship with the three of you?

Williams:

Well, first of all, we had to deal with all the group leaders, including David Leith. Charlotte had worked under David as the finance manager. Of course, Jonathan was no longer a group leader. He was director of the lab at that point. We had to deal with Jonathan. But he's an easy-going guy, actually. Very smart, fair minded and intelligent. He'll get his way if he wants to, but he wasn't like David. Richter, after all, knew him quite well. Jonathan worked for Richter in group C a long time ago and took over Group C when Richter replaced. Anyway, I kept up with all the group leaders setting up budgets and projects with Charlotte’s help. I can't remember them all at this point. And I wasn't spending any time at all in research, but I was having a ball, to tell you the truth, working with the DOE. Whenever they had something that Research Director didn't want to deal with, it was, “Go talk to them,” and I'd bring it back.

Zierler:

And what would be an example of that, something where you were dealing with the DOE and it was actually pleasant, it was productive?

Williams:

Oh, I can't remember all the things that came up. My memory is fading. That's my problem. All I remember is being happy with the working relationship at that point. Seems a busy blur today. Ultimately Persis became Lab Director when Jonathan went to become the Director of a new Japanese Lab. She was like David Leith, a pretty strong-minded research director. After all, she'd been a SLAC kid and her dad had been the deputy director so she probably felt like she owned the place. Persis had a really dynamic, open, strong, personality.

She didn't always agree with everybody on the physics that was being done, though. She had her own notion. She was actually doing atomic physics at Cornell. But she was very interested in the synchrotron radiation becoming a success because she saw it as the future of the laboratory. And the high-energy physics group leaders didn't always like that. They actually reorganized, and there was a LBL manager that I didn't know before. I can't remember his name at this point, but he was called the director of operations. I was moved out of being assistant research director to being manager of quality control under the director of operations. This was a big thing for DOE since the arc-flash accident. The DOE wanted us to really improve our quality control formality.

Zierler:

And Steve, was the idea there, was it a safety issue? Was it a scientific issue? What was the concern over the quality control?

Williams:

Yes, a safety issue. There were accidents at SLAC. There was a famous accident in 2004-5[?]. An electrical contractor working in the accelerator housing was electrocuted—didn't kill himself but he got severely injured in an electrical accident—coming in contact with 480 volts because he was using an uninsulated screwdriver to work inside a breaker box. I saw a picture of his shirt lying on the ground, not on him. He got burned. It was just carbon all along the edges of the back of the denim shirt and nothing in the front. There was a flash flame that vaporized the front of the shirt. He had suffered severe injuries, but he survived, and had quite a pension from Stanford University worth millions of dollars, I think. And he was a contractor brought in from the East Coast. He went back to the East Coast and retired with lots of money, but he didn't look that good. He was severely burned.

That was a question of SLAC’s lack of rigor supervision and dealing with contractors and how the rules were or weren’t laid out in front of them. So that tightened up a lot of the contractor management things at SLAC, including research users that were literally working like contractors because they come to the lab to do physics, but they have to know the rules, too, so you've got to train them. So, there's a lot of training issues for persons doing work with sufficient safety training. I was just an advocate for that, making sure things got done and reporting back to the director of operations. He and I didn't have such a close relationship. My wife had had quite a few illnesses up to that point, and eventually got lung cancer. But she'd had falling problems and she was in a wheelchair at that point. I said, “Ok, Steve, it's time to retire.” I was 68. Wanted to work until 75, but I said, “I can't do that to her. I have to retire now.” And she lived for another five or six years, so we had some good times, including going to the Rose Bowl and the Rose Parade six months before she finally passed away.

Zierler:

Oh, that's nice. Steve, did you feel that, despite the inevitable tensions that must've arisen with DOE, that SLAC needed that oversight to prevent these issues from happening, and was it successful, the oversight, in that regard?

Williams:

We didn't have another accident like that one, which happened under Jonathan Dorfan's watch, and ultimately hurt him because he was the director at the time. He lasted a few more years, but he stepped down and a synchrotron light physicist took over the lab as the lab was becoming largely a Synchrotron radiation lab. I learned a lot about quality assurance in that year in terms of the meticulousness of a quality assurance manager. I always thought of physicists as being pretty careful and very knowledgeable for physics and the possible dangers. But quality assurance is rule based. Physicists are science knowledge based. If you're not a physicist working with these things, you've got to be taught how to work with high voltage. You can't just assume that the guy's going to respect it because of anecdotal stories he hears about it like this one.

But quality assurance was a management rigor, and it wasn't taught from the science perspective, it was taught from how to be absolutely safe based on established, documented procedures. People, physicists especially, found this overbearing. I tried to adopt the notion that it wasn't overbearing, that it was just a matter of “proceduralizing” risky things. I thought that was a good idea, but I don't know, a lot of physicists thought they could “proceduralize” it by themselves because they understood the physics behind it. That wasn't true for someone who wasn't a physicist, like a mechanic, electrician or electronics person. They may not have that kind of training. So it was a hard go for me and it was just becoming boring. My wife needed me, and it was time for me to leave and go and spend some time with her, which I did for a long time until she died.

Zierler:

Steve, I'd like to end our discussion asking a broadly retrospective question, and I think you're uniquely suited to answer it because you had a repetition in your career. You joined SLAC and you left, and you joined SLAC and you left.

Williams:

Yes. That's one unique thing about me.

Zierler:

That means that you have a very unique insider/outsider perspective to SLAC that either category would not necessarily have. In other words, I've talked to many of your colleagues who all they ever knew was SLAC, so they never had an outside perspective. And then, I've talked to a lot of people who appreciate and respect what SLAC has done over the decades, but never got to see it from the inside. I've learned over the course of this larger oral history project with SLAC, as you well know, that the research direction, even the ideology or the mission of SLAC, has changed enormously from—

Williams:

Yeah. Sure.

Zierler:

—Panofsky's original vision in the early 1960s to the many ways that SLAC has reinvented itself where today particle physics is really not front and center, let's say.

Williams:

Yeah. No, that's true.

Zierler:

From your perspective, how has SLAC changed and how might your career trajectory of being both an insider and an outsider offer unique perspective on that particular question?

Williams:

It is true that I felt very confident being a graduate student and then a postdoc and then a staff member working with David Leith, whom I got along with so perfectly, when my friend, Leon Kaufman called me and asked me to interview as an assistant professor in physics in the nuclear medicine department and told me about these wonderful detectors. And it always appealed to me to work on medical detectors. I don't think I'd really transitioned at that point into management yet. I was still doing a lot of electronics on various detectors and beginning to work on the Cherenkov imaging stuff but on my own, buying all my materials and making my tests. I have loved tinkering since I was a kid. So here I was working with these exotic chemicals for photons with a particle detector in order to measure their position. So it was a lot of fun.

But Leon called me up and said, “How'd you like to become an assistant professor in physics at UCSF Medical Center?” I said, “Um, could be.” I would become a faculty member, a new feather in my cap. So off I went, intrigued by it. The pay wasn't that much different, but it was a change of venue. At that point in my life I didn't know whether I would stay at SLAC for my career. I decided to take this opportunity to try a medical technology career. Medicine seemed a career much more justifiable to society than particle physics. Particle physics research seemed remote to the average citizen. I cared, but most people didn't even know what it was. But medicine, everybody's been in a hospital, everybody knows about all these wonderful machines that people develop.

So it was an opportunity to do that with a new technology for imaging and photons using germanium detectors. Germanium was unique because it can fully absorb and measure the low-energy X-ray and be able to distinguish a high energy gamma ray from a low energy X-ray, for instance, because it produced a much bigger pulse in the geranium. Of course, you had to attach a radioactive atom to an organic chemical that would move through the body and attach itself to a tumor that you wanted “to see”. It was just a new world that would make my knowledge more relevant to society. So off I went to UC Med Center in SF. I had a fun year but ended up not being comfortable with working for Leon, as he was the professor and leader of the group. He had quite a reputation at that point. He'd moved his entire lab out from near the Golden Gate Park site of the medical center. The new lab needed more space that wasn’t available on Parnassus Street hospital site.

For one thing, the lab needed room for one or two large magnets for experimental MRI machines with a magnetic field that needed either space or iron shielding to contain the fields. You just couldn't put that next to somebody else's lab in the UC Medical Center in SF without a lot of magnetic field extending into nearby rooms. There were a lot of buildings north of the airport that were convenient for the lab. Since I lived down the Peninsula, it was more convenient for me to drive there. So, I spent a few months there. But it just got to the point where Leon had one too many blow-ups. I'm a nice guy. And David Leith and I got along superbly. I didn’t tolerate anger from Leon when he didn’t like a result which I was honest about. So... I called up David Leith again and went back to SLAC and had another glorious time for seven more years at SLAC where I resumed working on the SLD Cerenkov detector and other interesting physics projects.

But... I was attracted back to Leon’s world, not by Leon so much as the MRI industry that developed out of great progress at his laboratory. It was an opportunity to work in a medical industry that I thought would be interesting. The money, in the private sector, was a lot higher than I was making at SLAC at the time. So, I went to Diasonics, Inc., in 1985 as the Director of Engineering and was paid much higher than I was at SLAC. Working in industry gave me a new perspective. I had a unique position to be hired as the Diasonics interface to Leon, Inc., which was across the street.

The SLAC Business Manager had a DOE lab business manager's meeting in Arizona. He asked me to go to give a talk on my experience of working as a scientist in industry. So I prepared a talk entitled, "Working in Industry." I gave the talk to DOE business managers from other DOE facilities at the Arizona meeting. I also gave it at SLAC to the staff there. I think it was pretty unique and well received. I described the career paths for people in industry versus the career paths in physics. A lot of people enjoyed what I learned there, and perhaps it even solved their desire to leave because they said, “Oh, ok. I can see you have problems in industry too.”

But there's nothing like going to a trade show at McCormick Place in Chicago. It's just impressive—the lengths the industry goes to to sell stuff. Particle physicists don't sell things. Well, they do in the sense of convincing someone of an idea. But selling things in an industrial trade show was really an anomaly to me, especially when, after hours at the show, the salesman from this company would be introduced by the sales guys from the other companies with whom they used to work, and they would invite them into their booth, which they weren't allowed to do during the day. But they'd be talking to them all about their products and, after all, who knows, maybe he'd be in one of the other salesman’s companies in a few weeks. So, it was more of a dog-eat-dog world of competition compared to SLAC where it's more collegial cooperation throughout the other physics labs. Finally, I went over the pluses and minuses of working in industry versus SLAC. That’s why I came back to SLAC finally and spent the rest of my career there. Happily ever after.

I once had an opportunity to give a talk in Russia at a Novosibirsk physics laboratory. It was a particle physics instrumentation conference with technology scientists from the United States, Europe and Russia. It was rotated between three countries every two years. I thought that was unique to be able to go and give a talk about my work with Cherenkov (a Russian, after all) ring-imaging radiation detectors. So, David allowed me to go there and give the talk. That was a fascinating tour. I spent eight days in Novosibirsk, which is in the middle of Russia (Siberia) in the wintertime in March. That was a totally unique opportunity. The university also gives you great opportunities to travel if you can take them.

Zierler:

Steve, I'd like to thank you for spending this time with me. It's really special to hear your perspective and your memory going back, not quite to the beginning, but at this point pretty close to the beginning of SLAC and having all of this perspective.

Williams:

Yeah. It started in, what, '60-...

Zierler:

It depends how you count, but maybe '63.

Williams:

I'm talking about turning the machine on, I think it was in, like, '66. I think in '67 when I was running my experiment at SLAC for my PhD thesis with a monoenergetic photon beam. And it was a joy.

Zierler:

Indeed. Steve, it was great spending this time with you. Thank you so much.