Pioneers in Science and Technology Series: William Brobeck

              
PIONEERS IN SCIENCE AND TECHNOLOGY SERIES


ORAL HISTORY OF WILLIAM BROBECK
Interviewed by Clarence Larson
Filmed by Jane Larson
January 3, 1985
Transcribed by Jordan Reed

 
MR. BROBECK: …I guess you’d like to hear a little bit of my early life.
MR. LARSON: Very good.
MR. BROBECK: I was born in Berkley, where we are right now and of course where the University of California originated and where the cyclotron laboratories have been. My father was an attorney in San Francisco who was, lived through the earthquake and moved to Berkeley right after the earthquake and that is where I was born a couple of years later. I went through the grade schools here and then to Stanford. I have always wanted to be an engineer. I have always like mechanical things and there wasn’t any question in my mind about what I should do.
MR. LARSON: So you were determined on the field of engineering at a very early age.
MR. BROBECK: Oh yes. I think probably six or seven years old, something like that. I use to play with Meccano outfits. I was fascinated by them and I use to wire up light bulbs and that sort of thing. 
MR. LARSON: As a matter of fact, I’ll mention a lot of engineers got their start with the Meccano sets, chemistry sets, and so on.
MR. BROBECK: Physicists and chemists too, I’d say. Yes. I went to Stanford for my undergraduate work in the engineering school. It was a pretty broad education at Stanford, for which I am very thankful that they didn’t concentrate as many schools do on the technical things. Then after graduating in 1930, I went to work for a manufacturer, what had been steam automobiles in the area, which was a fascinating subject and after about a year of that I went back to MIT for a master’s degree which took me two years and gave me a good view of the differences between MIT and Stanford. I can’t help thinking that Stanford had the edge. Then I came back to the west and worked for some more time with that company. At that time they were developing a type of steam power car which was to be run on the railroad in competition with the diesel engines which were just then coming on in use. There was some hope that steam might still be competitive with the diesel. Well as time went on that hope grew weaker and weaker. So I finally left them with somewhat of a loose end and I was looking around, I was getting ideas. I went to the university library and happened to run on an article on the cyclotron by Franz Kurie who I’d known of.
MR. LARSON: What year was that?
MR. BROBECK: That was ’37.
MR. LARSON: ’37.
MR. BROBECK: Yes, and I was, the cyclotron sounded very intriguing, but what impressed me most was that I could understand the equations, the resonance. Realizing and reading that it was right there in the next building practically. I went over to see what was going on and met Don Cooksey. That was the building that was the old, had been the mechanical engineering laboratory for the university, but it had been turned over to Professor [Ernest] Lawrence at that time for the cyclotron laboratory.
MR. LARSON: Yes, what size was the cyclotron?
MR. BROBECK: It was 27-inches.
MR. LARSON: Oh, it was 27-inches.
MR. BROBECK: Yes, and it was built out of the big magnet that had been used for a radio transmitter and which had been donated to the university and the cyclotron had been around then you see for, I guess, since 1930 or ’31. It was six or seven years old. So it was in some ways a fairly mature business, although you wouldn’t know it from the way people were acting. So, Don seemed to feel that I could be useful. Fortunately I was in the position where I could have a job. So I was able to contribute my time to the operation. So Ernest was away at the time. He said that when Ernest came back he could tell me whether I could actually work there or not. So a few days later Ernest did come back and I talked to him and seemed pleased to have somebody at least who was called an engineer on the job. At that time I’m not sure whether Wren Salisbury was there or not, but the 60-inch cyclotron was being designed at the time and the 27-inch cyclotron was just about to be replaced with a 37-inch tank.
MR. LARSON: Oh yes.
MR. BROBECK: That was a big step forward because up until that time all the tanks had been sealed with wax.
MR. LARSON: Oh yes. Well, that was pretty crude, although a tremendous amount of work was done on the 27-inch.
MR. BROBECK: That’s right. The idea of “science”, which I had never paid a great deal of attention to science. I had taken science courses and so on, but I had never had any idea of being a scientist, and still don’t. I’m an engineer, but you know the whole activity there was just discovering things hand over fist, you might say. One of the things that I noticed, that everybody noticed was the big isotope chart, a big board on the wall and it had hooks in it for the labels for the isotopes that are being discovered.
MR. LARSON: Well, I guess at that particular time, the new radioactive isotopes would come by at least one a week.
MR. BROBECK: At least, I guess and I know when the Physical Review came out, I think it came out weekly at that time, at least some edition of it, I’m not sure, but one of the physicists would read what the isotopes that had been discovered so since the last issue and make labels to hang on this chart. A good many of these labels were discoveries made right there in that laboratory.
MR. LARSON: That’s a fascinating story.
MR. BROBECK: It was obvious that science was advancing right before my eyes there and the people waited very anxiously, of course they kept the machine running on the bombardments. I was interested in the machine. I didn’t take any, I didn’t have much to do with the isotopes, but I didn’t do that part of it, but I liked the machine as being a complicated electro-mechanical device. So I was given more and more to do in keeping the machine running, so that the physicists were more relieved of that and could work on their experiments. 
MR. LARSON: Yes. I imagine that good engineering would help to keep that machine running a greater percentage of the time. Some of the early machines must have had a tremendous amount of down time.
MR. BROBECK: That’s true. It didn’t have to be especially good engineering, just engineering. The physicists looked at the apparatus, any kind of apparatus, it’s made just for the experiment, and they don’t consider that it has to keep running particularly. Usually when the experiment is over, even though the machine is about to collapse, nobody cares because the work has been done, but in the case of the cyclotron, there was so much further use for it. The reliability did have some significance and of course made things go more slowly when you had to do a better job. Of course, I didn’t object to that at all. Although the physicists would want to get on with their experiments, they didn’t care if the machine fell apart, after they finished or not.
MR. LARSON: Characteristic of them.
MR. BROBECK: So, they were just great. I enjoyed that very much. 
MR. LARSON: So you have then, you participated then in the design and construction of the 50-inch machine.
MR. BROBECK: Well, yes. It was interesting you mentioned the 50-inch, because it was known as a 60-inch. It was 60-inches, but it started life as a 50-inch machine, and if you don’t mind a long winded story.
MR. LARSON: No, this is fascinating. 
MR. BROBECK: A few weeks after I got to the laboratory, the 37-inch vacuum chamber was pulled out and the 27-inch was pulled and the 37-inch was put in. That was the first one to use gaskets like ordinary engineering design. I had nothing to do with the design of it. It was designed before I got there, but it was quite a departure to use rubber gaskets because the rubber was under suspicion in vacuum systems anyway. So, when it was first pumped down, the pressure stayed high as most new machines do and it seemed the physicists were beginning to worry about whether they could get a vacuum with these rubber gaskets. They were talking about replacing, pulling the tank apart and waxing it. But after the second week, a week of pumping, and the second week, the pressure began to come down. It came down very well and every one was just euphorious. Ernest Lawrence was just so enthused that he thought we, everything is so great, let’s increase the 50-inch cyclotron to 60-inches, (Laughter) which he did. 
MR. LARSON: How did you, well, did you have to redesign the magnets?
MR. BROBECK: Well, that was the way he operated and he said, “You can do it alright.” (Laughter) And that was the way he always was. He had so much confidence in people’s ability that they just sort of rose to the occasion. Well I don’t remember that there was any great problem because I don’t think the iron, they had really started manufacturing it yet, but we did change the drawings. There was a draftsman who worked with the WPA [Works Progress Administration] which was active at that time and he got, started on a new piece of paper and started drawing for the 60-inch cyclotron and that’s what it turned out to be. 
MR. LARSON: Who made the magnet incidentally?
MR. BROBECK: For the 60-inch?
MR. LARSON: Yeah.
MR. BROBECK: As I recall, it was United States Steel and the, it was machined at the Moore shipyard.
MR. LARSON: Oh yes. Yes, well that was quite a landmark at that time to get a 60-inch cyclotron. 
MR. BROBECK: It was designed more carefully to keep running. Up to that time, the thing had been sort of like laboratory experiments, this was more like a piece of laboratory equipment you might say. 
MR. LARSON: So as far as the sources and everything else is concerned, once you’ve finished your run, you could get back into operation pretty quickly. 
MR. BROBECK: Yes. It had some very good features. A control was very simple. It was possible to shut down the cyclotron. If everybody had to go to class, they could shut it down and in an hour later they could come back and turn it on.
MR. LARSON: Oh yes. 
MR. BROBECK: In later years, it got to be such an operation to turn on the cyclotron, it took an hour to turn it on.
MR. LARSON: Oh yes.
MR. BROBECK: Ed McMillan worked out a control system for that, to turn it on and off that was very effective.
MR. LARSON: Well, let’s see. Then you had to design the radio frequency system…
MR. BROBECK: Yes.
MR. LARSON: …to go with the 60-inch cyclotron.
MR. BROBECK: Yes. Wren Salisbury had a lot to do with that. He built the oscillator for the cyclotron, a big aluminum box with a home-made tube in it, power tubes that were made there at the laboratory. They were the ones that Dave Sloan had developed for the x-ray tube over in the San Francisco Hospital which had been developed several years earlier. We had a couple of high power tubes that had been sent out I think from Western Electric that we might use. I guess they were donated or something, but they were unrepairable and nobody wanted to try. They thought if they damaged them, they would be gone, whereas the home-made tubes were repairable. They were taken apart and fixed and put back together again. Of course they weren’t awfully good tubes, but they were made right there in the shops and worked on so they were much more economical. In fact, money was very short in those days.
MR. LARSON: Yes. Approximately what power were those?
MR. BROBECK: I think they were like 100 kilowatt tubes. They were big tubes and took a lot of power for the cyclotron.
MR. LARSON: Yes, well a kilowatt vacuum tube used to be considered a tremendous vacuum tube.
MR. BROBECK: These were the, among the highest that could be built up at the time.
MR. LARSON: Oh yes.  Fine. Then apparently the 60-inch cyclotron operated very well. What was the, how soon after was the next step up?
MR. BROBECK: Well when the 60-inch got into steady operation, Ernest of course began thinking, or began talking, he’d probably been thinking before, for the next cyclotron. This was the one that became 184-inch. He raised money for it through the Rockefeller Foundation and I think a couple of other smaller foundations. I think the university contributed also. I can remember Warren Weaver coming out and visiting and talking about this great cyclotron, as Ernest tended to call it. It was obviously too big to put near where the 60-inch and 37-inch was down on the campus. There wasn’t that much room. I remember we went on a sight expedition and settled on a spot above the big “C” on the hill that the students made. “C” for California and there was a knoll just behind that letter and that is where the cyclotron was put.
MR. LARSON: That was the designated site for the 184-inch.
MR. BROBECK: Yeah. That was, of course the war was beginning to come closer about that time and I was working on drawings of the coils and the magnets. We had a magnet test set up and Emilio Segre was working on that and Charlton Cooksey, Don Cooksey’s brother was out, I guess on sabbatical or something, and he worked on the magnet design. Things were going very steadily as I remember. It was suppose to be 100 MEV [mega electron volt] of protons. About the time the magnet was on order, all the steel was on order, the copper, the paper by Beta came out in the Physical Review on the theory of the cyclotron, which I don’t think Berkeley people paid much attention to. This was analyzing the acceleration, the de-voltage required to keep the particles in resonance and of course as the relativistic increase in mass occurred at higher energies, the particles tended to get farther out of resonance and that could only be overcome by reducing the number of revolutions which meant more voltage. So there was a relation between energy and voltage and as I recall the voltage went up with the square of the energy, the de-voltage required. Beta in its concluding paragraph said that considering the problem with higher voltage and the rapid increase, it didn’t look like cyclotrons would be practical above about 25 MEV, and we were working on 100. (Laughter)
MR. LARSON: That’s interesting. Let’s see. Did you resort to anything like a shimming to help the relativistic problem.
MR. BROBECK: Well I guess the answer is no. There was shimming done, but this was a shock to the laboratory and at that time Bob Wilson was a graduate student and was writing a paper on the cyclotron which paralleled Beta’s paper and he said the same thing to the effect, although he didn’t conclude the same. There was no question about the theory. You couldn’t get around that. So Ernest had the cyclotron redesigned for deuterons instead of protons which of course would have less increased mass for the same total energy, and he wanted the de-voltage to be a million volts. 
MR. LARSON: Fantastic.
MR. BROBECK: The x-ray tube in the San Francisco Hospital was running at a million volts and so it wasn’t absurd, it was just difficult. I guess everyone felt pretty worried about it, but the gap of the cyclotron was increased to get more ground clearance and of course that would reduce the magnetic field that the redesign was for 100 MEV deuterons with a large gap and a very high de-voltage, but that’s about then that work was shut down because of the war.
MR. LARSON: Oh yes. So then the conversion from that to isotope separation was necessary. What, I guess that almost must have been coincident with the outbreak of war, was it?
MR. BROBECK: Well, I’m not quite sure really about the dates, but the war was getting closer all the time and I think about six months before Pearl Harbor, at least six months, we were working on a war basis at the laboratory because it was known that the bomb project was a possibility and they were getting money to support the work there at Berkeley. I started working on the uranium separation which was of course the thing that we were assigned and we worked on. The 184-inch magnet was under construction. In fact the first erection of steel had been before the war. I can remember that as being sort of relaxed. We watched what was going on on the hill. They had to drill 10,000 holes or burn 10,000 holes in the plates we had built the equipment for. So it was made out of plates and big disks of steel and the quality and flatness of the plates was important because the thing would be pretty irregular if they didn’t get flat plates and as the time went on the plates got worse and worse because the steel mills were being pushed so much to get war materials out. Finally, unfortunately, the most critical plates were the worst ones, and they were closest to the pole because that was what was assembled last. We were talking about rejecting them. They said you could reject them, but you’ll never get anymore.
MR. LARSON: Oh my.
MR. BROBECK: We took them and Ernest was as usual very relaxed about many of these tolerances, the typical engineer, do everything just as well as you can, but in many cases, it’s not practical, desirable to improve on things. Good enough is good enough. No sense in doing more. So we took the plates and by that time I guess the war, we must have been in it, it must have been after Pearl Harbor. The magnet was then completed and then used for the uranium separation process for experimenting. It ran all through the war with a gap six feet high. You could walk through it if you weren’t too tall. 
MR. LARSON: Fantastic. 
MR. BROBECK: And ran at 3,500 gauss and it had two test crews working on the uranium separators, one on each side of the magnet. There was a platform up there because the pole piece, the bottom of the pole was six feet off the floor. So there was a work bench, I mean a control bench, control desk at each side and a crew of people working on each side of the magnet. The magnet stayed on all the time. They used non-magnetic tools and just worked in the magnetic field. 
MR. LARSON: Yes. Now, let’s see. The other two cyclotrons were they also adapted for other experiments in isotope separation. 
MR. BROBECK: Yes. They were used, not all on isotope separation. I wasn’t very close to what was going on on them. Before the, well before, actually the work moved up to the hill, we ran the 37-inch cyclotron as a mass spectrograph separator. That was one in which we, well I can remember Ernest asking me to start in making an ion source for this thing. It was such a change because there was no radiation. You could get right up close to things. They moved all the shielding out and we had a shutdown date set when this equipment was suppose to go in. I think it took two weeks to design it. It was very simple. And I remember Frank Oppenheimer was working on a thesis, right up to the last hour, trying to get some data on a lot of equipment that was on that cyclotron and when the time came to shut it down he just kept right on working tearing it apart and building the new equipment. He worked all night and started putting the new equipment in for the mass separator for the run the next morning. It was of course under great time pressure. Everybody realized the great importance of that. So we got a beam of uranium atoms and it worked quite a bit better than a lot of people expected. They convinced, the theory was you wouldn’t be able to get [inaudible] because the space out spreading of the beam, but it turned out that there was enough dirt in the tank to reduce electrons and neutralize the beam. They were trapped by the magnetic field so that the beam didn’t blow up as it had been anticipated. 
MR. LARSON: As I understand, calculations were made, if you got more than one micro-amp of uranium it would blow up.
MR. BROBECK: Well it should if it hadn’t been for this gas focusing I guess you would call it, it would have. That did save it, but still the beam was small. It was from a production standpoint awfully small. It, Ernest…
MR. LARSON: You were getting into the milliamps.
MR. BROBECK: Yes, that’s right. I don’t remember what we got on the first runs, but I remember we had a meter that was called a super-sensitive amp meter written on the top of it. It was in a big box. That’s what we started out with. One of the first, in the first few weeks we made a run to collect a sample to make for measurements, that were being made by somebody to make neutrons more efficient or something. I can remember running all night. I was with a group of people and we took about 24 hours I think to get enough material on the target to, for the purpose of the beam current that we were able to get. When we finished the run, we took out the target and there was nothing on it at all. It had been spun off as fast as it landed. It was obvious when you saw it so that the, we had to immediately make a target that caught the uranium on the bounce which is what was used from then on. But that was the kind of thing that happened. Then after that, shortly after that we moved up to the hill above the big “C” where the cyclotron magnet was being finished and that’s where most of the work went on. The 37-inch was then used for studies on the ion source and the arc discharge by a group of Englishmen eventually who worked quite a long time on that. 
MR. LARSON: Yes. I believe that didn’t [Mark] Oliphant join Lawrence about this time also?
MR. BROBECK: Late during the war I think. I don’t know what happened in the first year or so, but when this group came over from England, Oliphant was there and Massey was the one that worked on the 37-inch with three or four Englishmen. The 60-inch worked also, but I think they were doing mostly measurements of, that weren’t directly related to uranium separation. I didn’t have much contact with the 60-inch. 
MR. LARSON: Yes. Well those, the existence of those machines made it possible to cut years off of the mass production, mass spectrograph material. 
MR. BROBECK: Well, the real key to it was the presence of Ernest Lawrence, I think. 
MR. LARSON: Yes, that’s right. The brains there. 
MR. BROBECK: I read what I could about other countries’ efforts and they didn’t have Ernest Lawrence. 
MR. LARSON: Well, fine. Incidentally of course now that you were able to design the 184, of course the next step was for production and who got the concepts of the vertical beams and the racetracks and so forth and so on. I was wondering if you could elaborate on the next step that was taken in making the production operation of U-235.
MR. BROBECK: Well, I can tell you what, something that went on. Of course it was realized it would take a lot of mass separators because we knew that the output would increase, it still was going to take hundreds of these things and multiple arcs. So we I guess I made some sketches, early sketches and Wally Reynolds, an electrical engineer who [inaudible] the laboratory products originally from the grounds and buildings department, and then he later joined the laboratory, and I tried to make up some cost estimates, which were way too low for what it was going to amount to. Then Stone and Webster Engineering Company, Westinghouse, and General Electric were brought into the project and they brought engineers to Berkeley and so between all these engineers, by then there was maybe 100 engineers working on the job, and all these ideas generated. Most of these were very good people, and had ideas, and just where the idea of the racetrack came I don’t remember. Wilson Powell was in charge of the magnetic measurements and all these schemes were made with little model magnets. I can remember we had the question of whether to use a long stack [inaudible] with coils and cores and mass, the vacuum tank in between. That probably generated and developed as the most obvious way to do it, but there was the question of whether to make it a complete racetrack or whether to just let the field, the field return through the air. Because it didn’t take a lot of iron on the end to bring the reluctance down to a point where you could just let the… You know, we didn’t have to have a return path, but of course the question was could you work in all this, the stray field, which could be 20 gauss, or 50 gauss with everything moving around. So it was decided to close the ends. So the racetracks, the material was very critical. So much was being used for the war efforts and somebody had the idea of using silver. I don’t know who it was, instead of the copper, which was a very good idea.  I know we had a steel case core. The field was only 3,500 gauss so the course only had to be about 20 percent iron and couldn’t carry the flux. So we had cores made of egg crates of steel and they ran into a problem with the shipyards because they were making steel castings for ships and this was coming, I think, from Utah and there was this real bottleneck, but we were able to get the priority to get these castings, but later designed the magnets, the Alpha-2 designs were made out of sheet metal, just solid, because there was plenty of sheet rolling capacity in the country that wasn’t being used for automobiles and refrigerators and things like that. So that’s how, even though it was very inefficient from the standpoint of the use of iron, it made better use of the facilities. 
MR. LARSON: Incidentally, do you remember when it became apparent that there would be two stages necessary to reach the proper concentration of U-235, or was that apparent right from the start?
MR. BROBECK: I think it must have been apparent from the start because I, of course there is a need to know limitations that even kept us from even asking about what plans were. But I can’t believe, we didn’t know what the required purity was, and I never did know, I guess, all these years. It seems to me it was taken for granted that there had to be more than one stage. 
MR. LARSON: So an alpha unit and a beta unit. 
MR. BROBECK: Yes, so it was fortunate that it could be done in two stages.
MR. LARSON: That’s right because if there had to be another stage for all of the inherent complications and losses, and so on.
MR. BROBECK: It gets smaller as you go along, but anyways of course the beta stage had the problem of conserving the material and that meant that there was a big chemical problem there. They had to dissolve an awful lot of the machinery.
MR. LARSON: I’m very familiar with that part of it.
MR. BROBECK: I had very little to do with the beta design, almost all the work I did was on the alpha and then we later on when the alpha equipment was designed and quickly done it seems to me in retrospect. I went with the group to Oak Ridge, well actually, we were there, you remember, when the magnets had all that trouble.
MR. LARSON: Those were very dark days there.
MR. BROBECK: Yes. Ken Mackenzie suggested to Ernest that he send a group from Berkeley. So I was one of that group to start up a group of tanks in the Alpha-1 plant. These tanks came on very well. You probably were there.
MR. LARSON: Yes. I remember how there was a pessimism there whether they would every really be able to solve that shortage problem. Fortunately it cleared up with heroic efforts. 
MR. BROBECK: They were heroic all right. The shortage of the magnets was not, that wasn’t fundamental. I think it was, there wasn’t too much question, at least in my mind, whether it could be fixed. Whether the calutron would actually work was another question and it hadn’t worked very well up until the time the magnet shorted out. Of course the magnet shorting didn’t occur suddenly. It was a gradual thing with dirt accumulated, but they, I can see that the operating people, the Tennessee Eastman people were very discouraged from what they found out prior to the time the magnet went bad. So I was, always thought that Ken Mackenzie made a real contribution in recommending we start with 16 tanks I think it was that we ran back there.
MR. LARSON: Oh yes.
MR. BROBECK: Well, I came down with jaundice just about the time we got it running. So I was out of commission for quite a while. So that was up until about the end of my participation in the project. 
MR. LARSON: Well, once they got going past that point, of course the operation was very successful, and came on right on schedule.
MR. BROBECK: It improved steadily. It was a near thing, but it actually got enough material for the bomb in time to make it useful because another year would have been probably too late.
MR. LARSON: Yes. Actually, I believe E.O. Lawrence said that we had got to have it by July 1945 and it came right on schedule. Although we almost had to sweep up every milligram in order to get enough. Then so, well, of course the rest is all well known in history and with the completion of this then, presumably you returned your attention to other things at the radiation laboratory.
MR. BROBECK: Yes. I was, my wife and I and daughter lived in Oak Ridge, it seems to me for about nine months. There wasn’t much, I couldn’t accomplish much. Everything was in the hands of the operators by that time and it was a different period in the development. I remember Ernest coming and visiting us one evening and he was discussing the future of the laboratory, post-war. People were beginning to talk about what was going to happen after the war. He thought that the lab should have about six engineers. (Laughter) It said in some notes that I wrote that it’s seldom below 60; it’s probably more like 600.
MR. LARSON: When all of the, when things get started with full scale engineering effort was needed in every stage. In fact some of them could not have been done without systematic engineering.
MR. BROBECK: No and of course that is what engineering is suppose to be. We were on the way back when the bomb actually fell on Hiroshima. When I got back to the laboratory, we were driving back, we had enough gas tickets given to us to drive across and when we came to the laboratory, everybody was reading the Smyth report. Every place you looked people were reading the Smyth report, which I hadn’t seen before we drove to Berkeley, but apparently it had been handed out the day before or something. It was interesting that everything stopped for that. Then I think that the lab was back on the peacetime basis and about one week, Ernest Lawrence was saying do this, that and the other thing and get it going. There wasn’t, there was hardly any transition period at all. Everybody was welcomed. Many of the laboratory people were only working there during the war. I remember the chief draftsman we had was a bridge teacher. He went back to teaching bridge.
MR. LARSON: That’s fantastic.
MR. BROBECK: But he was our chief draftsman too. Luis [Alvarez] and Ed [McMillan] came from Los Alamos and Bob Martin had been with Tennessee Eastman as you know.
MR. LARSON: Oh yes.
MR. BROBECK: And they all had ideas. Of course, Ernest wanted to get the cyclotron running again and Ed and Vexler discovered the space stability which existed in the frequency modulated cyclotron. So that was pretty obviously the thing to look into with the cyclotron because of its million volt proposition four years before, looked worse all the time. Luis wanted to build a proton linear accelerator. Linear accelerators were being talked about. I think [John C.] Slater at MIT was about to build one, talking about building one. So, then Ed McMillan wanted to build the synchrotron to use as phase stability as your accelerating electrons. So, Ernest of course was enthusiastic about all of it and there seemed to be plenty of money, you know, so three crews were laid out. I was concerned with the cyclotron. Two of the other engineers, Edwin Gordon and Marvin Martin worked on the linac and the synchrotron. So linac had, Pete Penofsky worked for Luis on the linac and of course he was very productive. About a month or so after they started, Luis announced that it was no longer a proton linac, but it was now an electron linac. Oh, I’m sorry, maybe it’s the other way around, yeah. That’s right. It was the other way around. 
MR. LARSON: They converted from electron to…
MR. BROBECK: It wasn’t built yet. They were just planning. And ended up with a proton linac.
MR. LARSON: What voltages were they planning to go with?
MR. BROBECK: Upwards of 32 million volts for the linac and the synchrotron was 300 million volt electrons and the cyclotron was, I think it was 200 million deuterons. It was designed for... Ernest was, I wouldn’t say he was skeptical of the phase stability, but he was very cautious. I don’t know whether people realize that although he was very enthusiastic, he was also very cautious and he wasn’t going to start on to something that where he could make a test for it, which he decided to do. The 37-inch, I mean, yes, the 37-inch cyclotron was rebuilt, whole pieces were rebuilt to simulate the relativistic effect of the 200 MEV deuterons and a rotary condenser was built for it. It was run to accelerate at a low energy, but going through a very magnetic field would simulate it enough, the command chain, and it worked and that convinced Ernest. Up until that time, that time when the 37-inch actually accelerated with the system, we were still working on the original constant frequency design, but as soon as the 37-inch worked, it started over again, it turned out to be the final written draft. 
MR. LARSON: Yes. Well, what year was the synchrotron finally put into operation?
MR. BROBECK: It must have been, the summer of 1945 that we started and I think it was probably ’47. The synchrotron had quite a bit of trouble getting started due to, it had, the start of each accelerating cycle was a betatron and that field was so low, I think it was eight gauss before the radio frequency came on. It’s very hard to get a uniform feel, especially a uniform with that low field because it’s so effected by the residual magnetism and so on and the machine didn’t run for some months. Ed had a meeting of everybody who knew anything about betatrons. He couldn’t get the betatron part of it to work. I remember Don Hurst was out. I wasn’t very close to their deliberations, but I know they decided the field was too rough. Wilson Powell set about trimming it with trimming, bold face windings, sort of like a, smoothing it up and it did accelerate once the betatron acceleration occurred and the radio frequency acceleration didn’t give any predicted trouble. The magnet gave some trouble, which turned out to be that the neutrons were too close to switch the magnet on and off. It wasn’t a steady magnetic pulse and it made, I think, a full one cycle and then stopped. So that was, they were big neutrons like these, the big power tubes and the cables, the conductors that carried the current were too close to the tube, the magnetic field was effecting the arc inside the tubes. That was one of things that you can have a lot of trouble with, but they didn’t realize it. When they fixed that, I think that cleared up the power supply.
MR. LARSON: So switching these tremendous currents hadn’t been done before.
MR. BROBECK: Well I guess not. The accelerator certainly pushed the art of high power electronics. The cyclotron, that, I can’t remember anything, well the traumatic thing about it was the fire that we had. The coils were reconnected for the, when the pull, the gap was reduced and the, I don’t know why, it would have been running at a very low field during the war, 3500 gauss and we went up to I guess around 15,000 for the cyclotron, so the coils were reconnected and one set of the lower coil terminals were down on the bottom of the coil and apparently they accumulated dirt over the war years and when the boys put on different connectors down there, there was an arc under the coil and the coil caught fire and I couldn’t get it out. It was really touch and go because there was so much smoke from this coil. It was coming out of the bottom of the tank and burning. It was down in the pit and the building was filling up with smoke which was gradually coming down. Two engineers, Ken Copenhagen and Cedric Larson, who might be a relative of yours.
MR. LARSON: Nope.
MR. BROBECK: They were, fire extinguishers were no help. They, the fire department came and they didn’t, they couldn’t do anything. These two guys got a hold of a hose, a regular fire hose and they just got down in the pit and turned the hose on and blew it out, just brute force did it and saved the cyclotron.
MR. LARSON: That was a close call.
MR. BROBECK: It was, yes. So I don’t, we worked on that. It probably took a year, year and a half to get the, finish the design and get it turned on and it ran very nicely as I remember. The first few hours of looking for the beam didn’t work because the rotary condenser was running too fast. There wasn’t enough fuel to keep up with it. It wasn’t developing the de-voltage that it should have had. So, just by, somebody thought that was the trouble and slowed the condenser down and there came the beam. 
MR. LARSON: That must have been quite a moment.
MR. BROBECK: Yes, yes it was. It was a great moment. That was when, I hope I’m on your schedule.
MR. LARSON: Oh yes. Fine. Everything is, we have plenty of time, just relax.
MR. BROBECK: All right.
MR. LARSON: Those are very exciting things. I have never had the picture of before.
MR. BROBECK: Yes. then when the cyclotron ran, Ernest gave a party down at Pebble Beach for people that were mostly involved in it and he among others invited Dr. Robbie out from the east and there were others, Rockefeller Foundation and things like that that put up money and about that time, I had been making pictures of the bevatron you see because it seemed like the engineering part of a job always gets done and then there is a gap before the thing is built and then you’re trying to make it work. Well during this gap I was thinking about Ed McMillan’s ideas and the varying magnetic field and the frequency which was being discussed and I did some calculations on how a big machine could be built that way and I had made some drawings. I guess at Ernest’s instigation we published an article in the Review of Scientific Instruments on a 10-BE machine, just make it a nice round number. When we went down to this cyclotron celebration, Ernest showed these things to Robbie who was then looking for something for Brookhaven to do. 
MR. LARSON: Oh yes.
MR. BROBECK: Well, Ernest thought they shouldn’t take on anything so far out, because Ernest talks about things being far out.
MR. LARSON: Yes, that’s right.
MR. BROBECK: He thought they ought to build a cyclotron. Well, Brookhaven did buy a cyclotron, but they wanted to do something more dramatic obviously. So some months later we were called by Jim Fisk who was then the director of research at the AEC [Atomic Energy Commission] who told us that Brookhaven was proposing a proton synchrotron to the AEC would Berkeley be interested in doing something like that too. Of course we were.
MR. LARSON: Very timely.
MR. BROBECK: So we got out the drawings and made the proposal which was very easy to make and that was the basis of the bevatron project. When we got closer to building 10 million volts looked kind of big. The idea of making an anti-proton, you know was suggested as something required. I remember Penofsky figured out over night that it takes, I don’t know, 5.6 BEV [billion electron volts] and about 6 BEV would get you to that threshold. So that was what was selected for the energy and then 50 feet radius and I guess 15 kilo-gauss was required. It wasn’t pushing things too much, but the thing that was being pushed was the aperture and that was the big worry, whether it was enough aperture and of course this is a weak focusing machine. The beam makes approximately one cycle of radio, or vertical oscillation in a revolution and the previous machines, the biggest machines that we could use for a model for which we had any numbers on the space required for the beams was the bevatron and the synchrotron which were maybe five feet in diameter. We’re talking about 100 or so, and if you scale those off it, it’s impossible because each time the aperture would have been so big. Well I remember lots of discussion of what the aperture ought to be and Alfred Lumis was there at the time. I don’t know if you have perhaps heard of him.
MR. LARSON: Oh yes.
MR. BROBECK: A big supporter of Ernest and he thought that we ought to make the machine expandable in radius. We ought to build a small machine and then expand it larger. It didn’t look good at all. What we finally decided to do was build a machine with, based on the largest aperture we thought, that the laboratory thought was really safe and then provide for reducing that aperture later. So the first, the aperture, the largest aperture was to be four feet by I think six feet or eight. Four feet high, see the [inaudible] the Fermi lab was about like that and a mile in diameter. Anyway, there was a story. So they went ahead, the plan was to start out at that large aperture and get about 1.5 billion volts which still was a big number but it would be very relaxed focusing and everybody agreed that that ought to work, then we could build, put in these pole pieces later to reduce it. Well we, of course one of the parts of the belvatron idea was where to put it. There was an area north of the laboratory called the Wilson Track, it belonged to the university. It was beyond the laboratory boundaries north where it is now and it’s interesting that that was, I understand, that that was proposed for the United Nations Headquarters.
MR. LARSON: Oh, is that right?
MR. BROBECK: Yes, but because the night life in San Francisco wasn’t equal to that in New York, we saved the Wilson Track for the bevatron and so they started. That seemed fine, but the area, the terrain was not very good. It was hilly. In fact there is a ravine, a creek, Blackberry Creek. You’ve probably heard of Strawberry Creek, well Blackberry Creek was north and anyway the grading job was quite large to get that flat enough to get an area there. While that grading went on, it looked like we had time we could do something else. It didn’t look like building the machine was pressing because it was going to take about a year to get that area graded. Ernest thought the thing to do was to build a model of the machine, which we did, the so called novatron model. It’s a quarter scale model and we built that machine with modeling this very large aperture and it wasn’t too big. Instead of being about 100 feet, it was about 25 feet in diameter and it went to only a low field because they thought that all the trouble at once would be the low field. Once you got the beam circulating you were pretty sure it could keep it there. The amplitude of oscillation would die down and the aperture problem was going to be worse at the objection period. So we built this model and it took only nine months from the time we decided to build it until it was ready to test. It did give some trouble. We had some trouble finding the beam and getting it, which was due to the power supply fluctuation it turned out, but it did accelerate. Ernest could breathe a little more easily. That was one of the steps in the process, but by the time we had run the model and Ernest got more confident, he decided to go to the intermediate aperture.
MR. LARSON: What size was the intermediate?
MR. BROBECK: I think it was two feet if I remember, whatever the radii width, probably four. So that was the design. At the time, the MTA [Material Testing Accelerator] project started.
MR. LARSON: Yes.
MR. BROBECK: Now, the MTA project was at Livermore and it was a crash secret project at the time and it took precedence over the bevatron. So I worked on the MTA project and left the bevatron to one particular engineer was left in charge of it, who was sort of a care taker and we were hiring people for the MTA project and they were waiting for security clearance working on the bevatron. The thing didn’t go very fast as you can imagine, but we did get the coils wound during that period. The designs of the coils were all completed so it was a pretty straightforward job to wind them and it was done on one shift which was the plan, not to take more than one shift. So it was done under better conditions and more leisurely. When the MTA project ended, those coils were ready.
MR. LARSON: About how long did you work on the MTA project?
MR. BROBECK: I imagine we worked on it actively for about two years.
MR. LARSON: Oh yes.
MR. BROBECK: You would have to look at the records.
MR. LARSON: My recollection is about that time before it became apparent that the needs could be accomplished with reactors better. 
MR. BROBECK: Yes. There were lots of problems with that including the schedule. The schedule was so short that it couldn’t be met. It was worse than if it had been a longer schedule because people sort of gave up. They got so confused. We had several setbacks. By the time we did leave the MTA project to get back to the bevatron, Ernest’s enthusiasm reached the point where he could go to the smallest aperture. I wasn’t in favor of that, but Ed Laughtin was and so we had a meeting with Ernest and Ernest agreed that we ought to go to the smaller aperture. My feet weren’t quite as warm as they might have been, especially as we had everything all going from the larger aperture, but it was very wise to make the change because there wasn’t any problem with the smaller aperture and so it turned on about 1954, something like that; it was suppose to turn on about 1951. In the meantime, Brookhaven’s cosmotron had been finished and turned on and ran well. It’s interesting about naming the cosmotron and the bevatron, when the project was being considered, or I guess after the proved and Fisk came out to Berkeley from Brookhaven to sort of consolidate the design and verify what they were going to do and so on, he suggested that it would be good to call these machines which we now call proton synchrotrons, call then bevatron. Ernest didn’t like the word bevatron very much. He suggested one time cyclodrom, and as I pointed out that was a motorcycle race track.
MR. LARSON: That didn’t fly very well.
MR. BROBECK: No, but we had a sort of a vote, took a vote on names. Anyway bevatron won out, although in the newspapers it was usually called betatron because they had never heard of it before. 
MR. LARSON: How many billion volts did that reach?
MR. BROBECK: Six. 6.4 was the normal design. I think it reached, it was a margin over the energy required, the negative proton which was observed later on and I think was Segre and Chamberlin group of people. I was going to go on about the name. Brookhaven people had, since we were Berkeley, agreed to call their machine a bevatron also. When I got home, people out there didn’t agree to it, so they named it the cosmotron.
MR. LARSON: Oh yes.
MR. BROBECK: Of course billion has two meanings. It’s either 10 to the ninth or 10 to the twelfth.
MR. LARSON: Yes. 
MR. BROBECK: So it’s not a good name anyway, but that’s the one that stuck with the bevatron.
MR. LARSON: Yes well. So you got that one completed and it has currently fulfilled its mission there.
MR. BROBECK: Yes. As a matter of fact, the bigger the machines are the easier they are to design. They are more expensive and take more people of course, but the design problems aren’t as difficult.
MR. LARSON: That gave the physicists a wonderful tool then for exploring the high energy physics. 
MR. BROBECK: Yes, they made tremendous progress. There are of course many machines now that the strong focusing was a great, alternating grade in focusing was the great next breakthrough which made them step up in size and in more recent years, the use of colliding beams made the available energy to make [inaudible] increase. It seems like every one of these stages was just about as far as you could possibly go and then it would happen to breakthrough to something else.
MR. LARSON: Well, that’s a far cry from those first machines, the 27-inch, which got to, what is it? Ten million volts or what was that?
MR. BROBECK: Oh, I can’t quote it. I would imagine it was more like six. The 60-inch got to about 16, and I guess that the 27-inch must have been around 10. 
MR. LARSON: Well, you had some fascinating engineering experiences living through that whole area of accelerator physics. You mentioned that it was not too long after that that you decided to broaden out into other fields.
MR. BROBECK: Well, I thought I might like to try to do something more on my own. I can’t say that it’s been very impressive, but I don’t regret leaving the laboratory. The laboratory has changed after Ernest’s death and after the conditions, the site, they couldn’t build any bigger machines at Berkeley. The Fermi Lab machine was proposed, that project at Berkeley, but it’s hardly, it wasn’t a very good proposition, the proposal that was made here. So I don’t really regret leaving the laboratory. It was a great place to have been. Of course the center of gravity here has moved to Stanford now because of Penofsky. I think that’s really the person that’s important and he left Berkeley because of the loyalty oath controversy.
MR. LARSON: Oh yes. 
MR. BROBECK: But he’s very capable and that machine there is as you know the center of research and going ahead now…
MR. LARSON: Yes, a high energy business.
MR. BROBECK: …as a collider.
MR. LARSON: Yes. So, they have gone ahead tremendously in the voltages available for the high energy physics people. Fine. Well what are some of the engineering projects that you have carried out since leaving the laboratory, summarize those briefly.
MR. BROBECK: We had done some work for the various accelerator laboratories. Mostly it has been things like cost estimating because that’s a field that hasn’t been very well developed.
MR. LARSON: Yes, that became of much more importance as more and more people have gotten into the accelerator field. So you participated in quite a number of different accelerator projects as a consultant, consulting services.
MR. BROBECK: Yes, that’s right. We’ve also done some other things. We built a steam engine for a city bus that the state authorized and ran here in the area. As I mentioned earlier I was with a steam power company as soon as I got out of school. We developed a point of sale device that’s used in McDonald’s hamburgers.
MR. LARSON: So you have had quite a variety of experiences then.
MR. BROBECK: Yes. We’re now trying to promote and get support for a coal burning railroad locomotive. That’s interesting. These things are all interesting.
MR. LARSON: That’s right because the problem of oil shortages is always going to be facing us and then if in theory you can convert to coal, coal and oil, it’s an awful lot easier if you burn it directly with new technology. 
MR. BROBECK: Well, it’s hard to tell what’s going to come out. We’ve seen so many of these developments and all I can conclude is that it’s unpredictable to happen. I don’t see how you get there without trying. We’re trying to get support for that type of locomotive in which you convert from coal to gas right on the locomotive and then burn the gas. It looks like a good way to do it.
MR. LARSON: It looks like, well, you’ve had certainly a tremendous career in a lot of different fields. However, I guess most of your career started with the beginnings of accelerators and went almost all the way through to the modern generation. 
MR. BROBECK: Yes. I was fortunate to be there on the ground floor you might say. I also was very fortunate to be working under Ernest Lawrence. You know I can’t say too much in praise of his…
MR. LARSON: I think all of us who have worked with him feel the same way. That was a real rewarding experience.
MR. BROBECK: It was.
MR. LARSON: Well that, I think this has given us a tremendous insight into how some of these problems were solved that don’t quite all appear in the literature so to speak. I certainly want to thank you, Bill, for this addition to the record of science and technology in this field and I will, will hope that this tape will be of great help to future historians who want to look into how certain things were developed during this period. I think it’s going to be a field that historians are going to look into more and more in the future. 
MR. BROBECK: I’m certainly glad to do it. I can certainly give people the benefit of my memories of how things actually occurred.
MR. LARSON: Well, yes. Again thank you…
[End of Interview]