This is a transcript of the interview with George Trilling in Lawrence Berkeley National Lab, Berkeley, CA, as a part of the Oral Histories of Science Project of Foothill College. The interview was conducted in Dr. Trilling's office in Room 6032 of Building 50.
Interviewers: Hyo Jong Lee, Ruby Chung
June 27, 2006, 2:30 PM
Chung: Can you tell a little bit about yourself?
Trilling: Just a ... little bit about myself?
Chung: Yeah, like your major and um ...
Trilling: Well, first of all, one piece of personal history, I actually was born in Europe - I was born in Poland - I lived in France for the first nine and half years of my life; I went to France almost immediately after I was born; my parents, as I said, moved me to France. And then when I was 10 years old, I came to the United States; it was at that time, just before World War II had started in the United States. I came to the US in mid 1941; the war had already progressed considerably in Europe but it was, in any way, about to start in a few months later in United States. I lived in Los Angeles, as my parents moved to Los Angeles, and I went to junior high school, in Los Angeles. When I came to Los Angeles, essentially, I started in the seventh grade, yes, eighth grade and ninth grade to three years total, they call it a junior high school. And then tenth, eleventh, and twelfth grade I went to Hollywood High School. Then I graduated from Hollywood High School in 1947, of course, it was a long time ago,
Lee: (laughs) It's long time ago.
Trilling: Probably for you, a little bit more. In 1947, I graduated from Hollywood High School. My interest, at that time, were very much into scientific direction, I did quite well in my science courses; I've taken chemistry, both chemistry and physics, and math as high as it would be taught in the high school - I don't think that Advanced Placement courses existed at that time. And so in 1947, the fall of 1947, I started college at Caltech, California Institute of Technology in Pasadena.
Lee: That's a very good school.
Trilling: It's a very intensive school ...
Trilling: ...at that time, it was an all male ...
Lee: Oh really?
Trilling: ...school. Only men. When I got, well, this will come in a moment, I got my bachelor's degree after 4 years at Caltech in 1951, then I stayed for graduate school; I applied for graduate school in several places, got admitted at Caltech and decided to stay in Caltech for graduate school, and I got a PhD in physics in 1955. At that time, as I graduated, I got my PhD in physics in 1955, Caltech was no longer a school only for men; in my graduating class, PhD class, there was one woman, the first one, and the reason that she had gotten into Caltech, what started it all, now there're many woman at Caltech - there're distinguished faculty members at Caltech - but the reason that she had gotten in was that Caltech was extremely eager to appoint a new faculty member who was at MIT at that time, whose name was John Roberts and his graduate student was a woman. And he wouldn't move unless his graduate student could move with him and so, she moved to Caltech with him and Caltech became coeducational.
Trilling: Very few women, to start with, just one, but it built up considerably and now there are many women at Caltech. I don't know the ratio, but there are many, both on the faculty and the student body. And just to finish the facts about my history: I got my PhD, as I said, in 1955 at Caltech; I stayed one more year as a postdoctoral scientist, from 1955 to 1956; in 1956, I was appointed as a assistant professor at the University of Michigan.
Lee: Oh, University of Michigan? I'm transferring to University of Michigan.
Trilling: You're doing what?
Lee: I'm transferring to University of Michigan.
Trilling: Oh, you're transferring to University of Michigan. Yes, I was appointed in '56, actually, I didn't go there in '56; I went there in '57, because I got what was called a Fulbright Fellowship to France and I spent a year there as a post doc, my first post doctoral year, I spent in Paris, France. That was the year 1956-57. In '57 I went to Ann Arbor and joined the physics department at University of Michigan. And I stayed there from 1957 to 1960. In 1960, I got a job offer here in Berkeley so I came to Berkeley and I've been in Berkeley since 1960.
Lee: Oh, since 1960 ...
Trilling: and I ...
Lee: over 40 years ...
Trilling: Well, I've been there in 1960 so it's 46 years, not active the whole time - I'm retired, I retired in 1994 - I was there, non retired, from 1960 to 1994, for 34 years. And since 1994, I still have done some teaching and a little bit of research and so on but I'm officially retired. I still get to have a pleasant office for a while, I share it sometimes with somebody else, who sits here. Anyway, that does the rough outlines of my history.
Lee: That's quite a story.
Trilling: Now what questions would you like me to answer?
Chung: Ok, why did you choose the Berkeley Lab as your research ...
Trilling: Why did I choose ...
Chung: ...Berkeley Lab.
Trilling: ...Berkeley Lab and University of California at Berkeley. I came incidentally, I didn't say it, but I came as a faculty member at Berkeley so I was associated with both the department of physics and Berkeley Lab. I did research at Berkeley Lab, but I did teaching in the department of physics on campus. And why did I choose Berkeley Lab? Well, at that time I was, my field of interest, I didn't say that before, but my field of interests was elementary particle physics, experimental elementary particles study; it was basic constituents of matter, even sub-constituents of matter. It's a field, which it's been my privilege to see it develop from a very meager beginnings, not well understood beginnings, to an enormously developed stage, now. In 1960, when I came to Berkeley, there were the first big particle accelerators, atom smashers sometimes called, that had high enough energies, beams that you could create interesting new particles. Those big enough to do that, those machines, had just been built. And the most powerful one was in Berkeley.
Chung: So Stanford Linear Accelerator was built after?
Trilling: Stanford Linear Accelerator was built afterwards; it was built in the 1960s. Now, Stanford didn't really offer me a job anyway ...
Trilling: So it's a little bit of an academic question. But Stanford's linear accelerator was turned on in the mid 1960's - from, I think, 1965 or something like that. It was a very long linear accelerator, 2 miles long linear accelerator at SLAC, the Stanford Linear Accelerator Center. But at that time I came, the Bevatron at Berkeley was already built and it already been running for several years. So there was a very large accelerator-based particle physics activity. When I was a graduate student, we did particle physics with cosmic rays, that is, we waited for these particles to come down ...
Chung: To Earth.
Trilling: to Earth, from space. And the reason for that is that the needed energies were so high, when I was a student, the accelerators were not big enough, and by big enough, I mean high enough energy, to make these particles, so we used cosmic rays as our source, but they were relatively rare in the cosmic rays. Once you had accelerators, you could make the particles in large numbers -very large numbers. So Berkeley was really, very much at the lead in this particular field, it is the field I was interested in and they offered me a job. And there was another connection, here; when I worked at the University of Michigan, I worked with a very very distinguished, relatively young still, physicist by the name of Don Glaser; I don't know if you heard the name or not,
Trilling: Ok, Don Glaser, was a faculty member, he had also come from Caltech, got his PhD at Caltech a few years before me. He then went to University of Michigan and he invented something called the bubble chamber, a major instrument to study elementary particles. And that was in the early 1950's that he did this development, and in 1960 he got the Nobel Prize for his work, in fact.
But he decided to move to Berkeley in 1959. He came to Berkeley and he helped organize a possibility of my getting a job offer here at Berkeley. And so he helped me to secure a job here in Berkeley in 1960. So that's why I came to Berkeley.
Chung: I see. It's really interesting because, right now, we're taking physics class and it's a modern physics, so we're studying elementary particles and ...
Chung: ....things like that so ...
Trilling: I believe the beginning of elementary particle physics was really around the 1950's so it was a very very exciting field and the particles that were particularly interesting to us were something called the strange particles because their behavior was unexpected in certain ways, and it was just when I was starting graduate school that the first strange particles had ever been seen. And there were two that had been seen; I mean that's how many - two of them- in a cloud chamber. The two British physicists who discovered them, unfortunately, have now passed away; they should have gotten - it was such an outstanding discovery that they should have gotten the Nobel prize, but they never did. But anyway, these strange particles are fairly high mass particles so you need a high-energy machine to create them; it took the Bevatron - they had other machines called Cyclotrons, which were just not energetic enough to make the strange particles - and because you had to create a certain amount of mass, and transform the beam energy into that mass, only the Bevatron, and a slightly earlier machine called the Cosmotron that was built at Brookhaven few years before the one here in Berkeley made beams of sufficient energy. The one here in Berkeley was more powerful and it was called the Bevatron. And the term Bevatron comes from BeV, and BeV stands for billion electron volts. Billion electron volts were a measure of energy and it was a billion electron volts. And the Bevatron a machine that produced beams of 6 billion electron volts of energy.
Trilling: And the reason, I mean, let me just make a remark about it, the reason the machine was interesting and the six billion electron volts were interesting was that that was just enough energy to create what are called anti protons. Maybe in your class ...
Trilling: about particles you've heard about them, negative protons. Our world is full of positive protons in the nuclei of all atoms. But in nature there are no anti protons, the exact negative charged counterparts, but you can make them, if you have enough energy. So these were created out of energy, and the Bevatron was the first machine to create them. They celebrated the fiftieth anniversary of this a few months ago. It was done in 1955 so 50 years, 2005, the fall of 2005, there was a big celebration here, the fiftieth anniversary of the discovery of the anti proton in the Bevatron at Berkeley. Okay.
Trilling: Maybe I'm doing too much talking.
Chung: No, that's fine.
Lee: It's very interesting.
Chung: Yeah. Can you tell us of your biggest discovery?
Trilling: Biggest discovery. Well, the biggest discovery in which I was involved, you know, the work that I've done, almost all of it, has been done in teams. Initially, in the early years, the teams were a dozen people, between half a dozen and a dozen people, including both students and post-doctoral physicists, I was associated for a good part of the early stages of my career in Berkeley with another physicist by the name of Gerson Goldhaber, who is still here, just celebrated his 80 years birthday a year or so ago, anyway, so we had teams, so the greatest discovery in which I was involved was a team effort, was the discovery of what's called the charm particles. We were actually collaborating, we were a team and we were collaborating with another team, a pair of teams, at Stanford, at SLAC. And the experiment was done at the SLAC electron-positron collider. It's a machine which is called SPEAR. It stands for Stanford Positron Electron Asymmetric Ring. And the word, asymmetric, is just a letter there, it's a piece of history. The rings are symmetric, they have nothing to do with asymmetry, but it just sounds nice, SPEAR. So it was called SPEAR. And the discovery was made using that facility, knocking electrons and positrons with sufficient energy to be able to create a whole new family of particles that had been anticipated theoretically, or at least proposed theoretically, but they were discovered in 1974, November 1974, we'll all remember that famous day, November 1974, around I think November 10th or 11th of 1974. And the discovery was, the original discovery was, a simultaneous, between a group, an MIT group that was working at Brookhaven, led by a man by the name of Ting, Sam Ting, and our group, which was really led by a man from Stanford, by the name of Richter. Both Ting and Richter got, subsequently, the Nobel Prize for this work, leading this work and we were part of the team. So that was the most important work, discovery that I was involved with and participated with.
Chung: And you were part of Berkeley Lab or Stanford?
Trilling: Berkeley, yes, it was called the SLAC-LBL collaboration so it was just two institution. SLAC was the Stanford Linear Accelerator Center and LBL was us. Nowadays, it's LBNL, Lawrence Berkeley National Lab but in those days, it was just Lawrence Berkeley Lab; the "National" was added more recently. And this was done in 1974, as I said, so it's 32 years ago. And that was certainly the most exciting discovery.
Chung: So the Berkeley Lab, this is mainly a physics oriented lab ...
Trilling: Well, at that time, when all of this work was done, it was certainly a largely physics oriented lab. This is now no longer quite true; the lab has expanded in a number of different directions; there is a great deal of biology and biophysics and related areas and chemistry that is also being done. I'm part of what's called the physics division, and the physics division is only about, I don't remember the percentage exactly, it's less than ten percent of the lab. There is a nuclear science division which also really does physics. The physics division does high energy physics and nuclear science does somewhat lower energy work, but also a lot of it connected with elementary particles as well. Then there are programs in atomic physics; there is the so-called ALS, the Advanced Light Source here, which is also an accelerator of electrons, which is used to create x rays, high energy beams of what would be light if they were low energy but they are x rays, and they are used to study the properties of materials. That's also a branch of physics but a different branch of physics. So it's true that the emphasis is on probably, fairly I'd say, on physics and the tools of physics that is being used in variety of different directions: material science, biology; the lab is involved in the genome project and so on and so there are quite a number of different divisions; it also has an environmental program, and in fact the man who founded that program got the Fermi award of the Department of Energy a few weeks ago. So a very broad spectrum of opportunity.
Chung: I see.
Trilling: All scientific, of course.
Chung: The man who led the MIT team for the discovery of charm particles, how do you spell his name?
Trilling: T, I, N, G.
Chung: T, I, N, G.
Trilling: That's his last name. His first name is Sam.
Chung: And from Stanford, it was Rector?
Trilling: No, no, he's from MIT.
Chung: Oh, OK. And..
Trilling: The one at Stanford is Richter. Burton Richter. R, I, C, H, T, E, R.
Chung: Ok, and do you have anything to say to those who want to come to this field?
Trilling: "Come to this field", it depends on little bit on what you mean by "this field".
Chung: Nuclear and particle physics.
Trilling: Let's talk about particle physics. Particle physics, it requires a few words to answer that question, because particle physics has evolved very considerably. The kind of particle physics I'm talking about here involves accelerators, and it has evolved in the direction of particle accelerators of higher and higher energy. You need higher and higher energy because you're looking for particles which have higher and higher mass. And in order to create that mass out of energy, you need lots of energy. So you need to generate beams which are accelerated by electric forces, electric fields, to very very high energies. Now the problem, as you get to higher and higher energies, depends on little bit on what kind of particles you want to accelerate, but let's talk for a moment about accelerating protons. If you accelerate protons, the Bevatron accelerated protons, for example, and the biggest and highest energy machine is now being built in Geneva at a laboratory called CERN, and it also accelerates protons. The way you accelerate them is they go around in a kind of in a circle and each time they go through a certain areas where there are electric fields that accelerate them, they keep getting kicked and getting accelerated. But why do they go in a circle? The reason they all go in a circle is that there are magnets that bend them around. But as the proton energies get higher, you have to increase the strength of the magnets and the magnets only go so high. Nowadays people are using super conducting magnets so they go to higher field, quite high fields but still, there is a limit. And so, you have to build these machines bigger and bigger and bigger, and the biggest one that is now being built has a circumference of 16 miles.
Lee: 16 miles ...
Trilling: 16 miles.
Chung: miles ...
Trilling: It's near Geneva,
Trilling: ...at a laboratory called CERN.
Trilling: It's a European laboratory for particle physics and it's called CERN. The accelerator has a 16-mile circumference, approximately. So what happens is that it's, as you can well imagine, an enormously expensive, enormously complex, international project that U.S. is contributing to; it's being built in Europe because most of money that's paying for it comes from European countries, but the U.S. is contributing to it; Japan is contributing to it as well. What it does is it accelerates two beams of protons, which collide with each other to give you the maximum energy. Then of course you need a device to tell you, or set of devices, to tell you what happens when the two protons collide. An instrument that detects all the particles that are produced to see there are new particles or to see what's going on. So you need to build a detector, and these detectors are typically extremely complex. I mean, the scale of cost of an accelerator is in the several billion dollar range and the detectors is in the half a billion dollar to one billion dollar range so these are very complex devices and you need a very large collaborations to do the experiments; typical collaborations at this accelerator at CERN are about two thousand people.
Lee: Two thousand people ...
Trilling: Typically, two thousand people, international. And people have to go in time, to Geneva to the experiments and so it's very far from a table-top, experimental. Particle physics involves large collaborations, very large pieces of apparatus, and you know, very demanding analyses using all the computer capabilities that you can muster. You know ... some people like to work on their own, some people like to work in small groups, some people don't want to go and spend a large part of their time in Geneva or have some other distant place, they want to work in their own laboratories. So you know, whether people feel comfortable, different people will feel comfortable, or not so comfortable, working on such a large project. Now, why do people do this? Well, it's very exciting. The prospects of these new particles and how they fit in, and this brings me to another aspect of this which is that in the study of these particles, there is the beginnings of a connection between what's going on with these accelerator based experiments and the origin of our universe. Many of these particles that we created existed as particles in the early day when there were huge amounts of energy localized in the small space in the early parts of our universe. One of the things that you may have heard of, have you ever heard of the term, "dark matter"?
Chung: ...yes. It's anti matter, isn't it?
Trilling: No, this is not an anti matter. This is a dark matter. It's different. It's been discovered, and this is extraordinary, that most of the mass in our universe, dark matter, is not the stuff we're made of. It doesn't consist of protons and neutrons, and electrons, and so on; it's some other stuff. It doesn't shine; it doesn't have any of the properties essentially, except gravity. So it attracts each other but its mass is not anything like the mass that we're familiar with. One of the things that is hoped in this new accelerator in Geneva is to create new particles which might be the constituents of this mass.
Chung: Would it be like a black hole?
Trilling: Well, no, black hole is, of course, a very concentrated amount of material, maybe black holes are made up of this, in part, but this is mass which is just sort of spread out, at the edges of galaxies. How do we know this mass is there? We know it from its gravitational effects. We know it from the fact that by studying the motions of stars in distant galaxies, we can find that their motion is not accounted for by just the mass that we see. The mass we see is the mass of the stars or the mass that is consistent with protons and neutrons. There is some other mass in there, beyond that, which is, in fact, much larger amount than the protons, and neutrons, and electrons, maybe six or seven times as much that is there and its gravitational effects can be observed. I'm mentioning all of this because now there is an increasing connection between the particle physics that you do with accelerators and cosmology. And so, you can talk about particle cosmology or you can talk about particle physics. These are more closely related than they used to be. And in fact, the Department of Energy, which supports a large fraction of work in particle physics in the United States also now, because of this reason, supports work in cosmology. And there is a program here, I'm not involved with it, but there is a program here to send up a space vehicle to do observations, cosmological observations, supported by the high energy physics program of the Department of Energy.
Chung: You mentioned charm particles.
Chung: Is that same thing as charm quarks?
Trilling: Okay, charm particles are particles, which have, when we think of them as being made of quarks, at least one charm quark. And in 1974, what was discovered was actually a particle that consisted, from the quark point of view, of a charm quark and a charm anti quark. Just like the anti-proton, you have the anti-quark, which has the negative of the charge of the charm quark. The charm quark has a positive charge of two-thirds of an electron charge and the anti-quark is minus two-thirds. The charm quark is positive and the charm anti quark is negative. So charm particles are made up of, or have, charm quarks in them. Just like strange particles, although this was not known when they were discovered, strange particles are particles that have one of the quark constituents at least that is a strange quark.
Chung: I see.
Trilling: And the thing that is special about these particles, charm or strange, and what causes them to look strange at first is that they're kind of massive, and you wonder why they don't decay into a lighter quark. They actually do decay into lighter quarks but only very slowly and the reason that they decay very slowly is because they lose that strangeness or charm property. If you lose the charm or strange property and you decay into something else, something that doesn't have it, then it takes a long time, that's called a weak decay and it takes a long time for it to happen. This was a peculiar thing about strange particles that people didn't really understand; that's why they were called strange, and in fact they traveled centimeters before they decayed, so they took a long time. Many orders of magnitude longer than people expect. Essentially discovering the strange particles was the discovery of a new quark. People didn't know about quarks in those days but it was the discovery of the strange quark. Charm is the discovery of charm quark. Since then, we have discovered two more quarks: there is the B quark and there are B particles, which people are studying now, which have a B quark in them,
Chung: And there's T.
Trilling: And then the final one that has been discovered is what's called a top quark. And they come in families of two. The ordinary quarks we're all made of, that make us, are called up and down quarks, you might have heard of those, very light quarks. Protons and neutrons are made up only of up and down quarks. Then you have the charm and the strange quark, the next combination, that's what's called the second family; the first family is the up and down quark, second family is the charm and strange quarks. And the third family is the top and bottom quark, T and B quark. The B stands for bottom. Sometimes they use the word, "beauty" but ...
Chung: Truth and beauty.
Trilling: Truth and beauty, they use it, but the proper terms are top and bottom quarks, and people are studying extensively about top and bottom quarks. Top quark is very very massive; it's about a hundred and fifty times the, no it's almost two hundred times the mass of a proton. It's very very very heavy. The B quark is about five times the mass of a proton. The charm quark is maybe one, one and a half times the mass of a proton and so on, the strange quark a little lighter. So you have three families of quarks and with those three families of quarks you got three families of what are called the leptons. There's the electron, which we all know and love, that's part of us, does all of our chemistry; there is a heavy electron, which is called a muon, and there is a yet heavier electron or muon, which is called a tau. So you have three families of these particles going with three families of quarks. And nobody knows why we have three families. Because we're all just made up of one. Nobody knows why the world is made up of three and probably no more than three. There are reasons to believe that it's only three. As far as we know, it's only three. I'd be surprised if there were more than three.
Chung: (to Hyo Jong Lee) Do you have more questions?
Lee: No ...
Lee: Thank you very much
Trilling: Okay, if you have questions you can call, you know my phone number
Lee: It was very interesting
Trilling: So you can call me and you know, for me it was very exciting because when I started, none of this was really known, quarks weren't known
Trilling: You know, when I started, really, the first thing I ever heard about any of this was the discovery of the strange particles. And the experiment, you know, there was a cloud chamber experiment that had been done - I don't know if you're familiar with it - a cloud chamber is a box essentially with some alcohol vapor, the gas includes alcohol vapor, and at the right moment, since one of the wall is movable you very rapidly expand that wall, just pull it back very very rapidly; you have a mechanism that pull it back. And that expands the gas and cools it a little bit, and the alcohol that's in the form of a gas, alcohol vapor, condenses because it's getting cold so it forms droplets. And it turns out that if you have a charged particle that had just gone through, the droplets tend to form along the path of the charged particle. That's a cloud chamber and we were using this cloud chamber with the cosmic rays. And so, we were looking in my thesis experiment, for some of these strange particles in greater number to understand their properties, to understand how massive they were, to understand what they decayed into and so on, and so we had these cloud chambers running, and taking photographs of these tracks and occasionally, these tracks look like a particle that we were searching for. (Dr. Trilling gets up and looks around the shelves for a book) I don't know, everything got rearranged here so I don't know where ...
These are probably ...I don't have cloud chamber ... Have you ever seen bubble chamber pictures before? (takes out a book from a shelf)
Chung: The ones that look like ...
Trilling: (opens a page in the book) These are bubble chamber pictures. This is similar to cloud chambers but instead of forming a set of droplets, you form a set of bubbles in a overheated liquid and the interesting thing is what these strange particles look like. You have a strange particle which is neutral so you don't see it - you only see charged particles - so it's neutral so you don't see it and then it decays into a positive and a negative charged particles so you see these two particles. The parent strange particle travels centimeters, a few centimeters, before it decays. There's another one that has traveled a little bit further, you see, it's a neutral particle that came from this interactions and decayed here. So that's usually, you know, the thing that people were looking for and have been studying (points to another picture) and these are strange particles that you see here. And the thing that was peculiar was that they travel so far because they seem to be made so readily in the interaction, and if they're made readily, they should have decayed very readily, which means that they should have decayed right there and instead they were traveling centimeters and that's why they were called strange; we didn't understand it. Well, now we understand it; it's because they consist of different pieces; it consisted of a strange quark, which, normal things like protons and neutrons do not have. Anyway,
Chung: One more thing, can I have your address and phone number, and e-mail address?
Trilling: This I presume I can give you my office number here.
Chung: Uh huh
Dr. Trilling fills out paperwork
Lee: Thank you.
Chung: Thank you.
Trilling: And you're from Foothill College ...is that?
Lee: Yeah, we're from Foothill College.
Chung: And he's going to Michigan College next year ...
Trilling: University of Michigan
Lee: Yeah, University of Michigan
Chung: ...and I'm going to UCLA next year, I mean, this fall.
Trilling: UCLA, I know, University of Michigan, I know well, in fact, I was there a year ago, on a review committee. Are you planning to major in physics?
Lee: I'm planning to major in mechanical engineering.
Trilling: Oh, mechanical engineering. Well, University of Michigan is a very very nice university. You've been to Ann Arbor?
Lee: Oh, never. I've never been to it.
Trilling: Oh, you've never been to it? How did you choose the University of Michigan?
Lee: I just heard about it and then I just wanted to get out of here, California, because the weather is always same.
Trilling: The weather is not always the same in Michigan; I can tell you that.
Lee: Yeah, like Korea.
Trilling: I spent three years there and Ann Arbor is a very nice town. It's built up quite a lot in recent years; the University seems to be building and adding and it's a very very large university and it seems to be doing very very well. It's a very good place, I mean, in Ann Arbor is a very very nice town. Detroit, well, it's not so great, but most of the time you'll be spending in Ann Arbor rather than in Detroit. And it's a very good university. You'll enjoy it.
Lee: I'm very excited.
Trilling: UCLA is a good school too.
Trilling: I have many friends at UCLA and my daughter graduated from UCLA; she was an undergraduate at UCLA so lots of good things about UCLA I hear and it's a very nice place. Okay.
Chung: Thank you for the interview.
Lee: Thank you so much.