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Oral History Transcript — Dr. William Fowler

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Interview with Dr. William Fowler
By Charles Weiner
At California Institute of Technology
June 9, 1972

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William Fowler; June 9, 1972

ABSTRACT: Early education and career; graduate training at Caltech, with C.C. Lauritsenís group; collaboration at the Kellogg Lab and structure of Caltech physics department after 1939, Relationships with Oppenheimer and Lauritsen. Fowlerís and Caltechís war work, Lauritsenís role in setting up Office of Naval Research for federally funded post-war research.

Transcript

Session I | Session II | Session III | Session IV | Session V

Weiner:

Today is the 9th of June, and weíre proceeding in Dr. Fowlerís office. Yesterday we covered in general outline some of the major developments, some in quite specific detail. We mentioned the war period. We mentioned your postwar involvement and the decision taken here as to what the focus of work should be and its relationship to the work going on in the Observatory. But now Iíd like to go back and fill in a number of things. Some are sociological questions and some are quite specifically physics. Perhaps there are things that youíve thought of and that are on your outline that you want to cover as well. Let me ask the question that I mentioned at the end yesterday. That is, it seems to me that the work had three components here, the work in the group in which you participated. One was a development of the instruments themselves. By the end of the thirties, there were several accelerators.

Fowler:

Yes. Actually there were three Van de Graaff accelerators built in this laboratory, one before the war and two afterwards. All three of those are still operating, still being used.

Weiner:

Iíd like to take a look.

Fowler:

Yes, Iíll show you.

Weiner:

Well, thatís one process, the development of instruments and particularly the expertise of this lab, the development of detectors as well, simple cloud chamber, the quartz fiber electrometer. This represents a certain part of the work. The other is the use of all this for physics which we discussed, and we want to get back to that. The third is the use for biological work, medical work. I wonder whether there was a conscious division of time between these three functions, whether for example you felt any pressure on doing something toward the biological or the medical side?

Fowler:

No. As a student, I operated the million volt X-ray tube for cancer therapy, for patients brought from the county hospital, and I helped maintain the tube, but I found little interest in what the doctors were doing. I was mainly interested in the fact that I was earning a living doing that, but could use the apparatus for physics when I was free from operating it. Actually, very soon in my graduate career, I used the accelerator that Crane and Lauritsen had modified to accelerate ions rather than electrons, and so the period that I spent on the million volt X-ray tube here was just a job really. So I did not have very great interest in the medical end. On the other hand, Lauritsen did, because he made probably one of the earliest studies and one of the most complete studies of the depth-dose problem. But I never got very much interested in that. I talked about it with Charlie, because it had some connections with a lot of the other things that we were doing. But Iím not sure Iím answering your question. That end of it was primarily Charlieís interest, and then all the MDís that were here, Dr. Mudd primarily and then Dr. Stewart Harrison, who now is the chief radiologist at the Huntington Memorial Hospital here in Pasadena, very good friend of all of us. Heís on the medical advisory staff here at the Institute. But Charlie did not attempt to get any of his students, as far as I know, to do theses in the medical end. He considered that was the way that he paid for the operation of the laboratory.

Weiner:

How about his own time? How much of his own time was given to that?

Fowler:

There was a time when Charlie was working on the depth-dose problem. This was in part theoretical, but he spent quite a bit of time on it. But then once he finished that, then as I remember he was in the laboratory practically all of the time. This period that Iím referring to, when he was working on the depth-dose, was only for about one year, about the first year I was here, and he had apparently been working on that previously. But I thought that one thing we ought to talk about was my student-teacher relationship with Lauritsen, what I learned from Charlie because yesterday I may have given you the impression that the main thing he taught me was how to use the lathe. I think itís fair to say that the main thing that I learned from Lauritsen was how to do experiments, starting from how to construct the equipment, how to set up the controls, how to make sure that the results were meaningful, and how to estimate the errors in the measurement. That, plus the fact that he taught me a great deal about something that was very relevant to nuclear physics, still is, namely, the interaction of radiation and particles with matter, in a very practical sense.

If you want to cut this particular gamma radiation intensity in half, he knew roughly the thickness of an aluminum absorber, or of a lead absorber needed. He just had a great wealth of empirical information of that kind, so that when we went to do an experiment, and we did a lot on trying to measure the gamma ray energies by their absorption coefficients, I had some guidance in what ballpark you started. He knew about the range of protons in air and the range of alpha particles in air, and directly from him I began to appreciate, in doing experiments under his direction, how important those things were, and then I could always find in the literature detailed graphs and tables. Then, in regard to what we tried to do in those early days, I would say that Charlie was not really terribly interested in the nuclear theory per se. What he wanted to know from Oppenheimer was, given this experiment, given this theoretical interpretation, what do you do next? Charlie was always on the lookout for good experiments to do next, and I would say thatís another thing that I learned from him, not to go off trying to improve some experiments that you might have come to love beyond the point where it seemed of any significance to Oppenheimer, but just to stop, go build some new equipment, take a lot of time out, do a lot of hard work if necessary in order to make some new observations that Oppenheimer or Tolman or the others thought were relevant. So now, itís true, that in the last decade, Iíve not been as active in the laboratory as I was for the previous 25 years.

But nonetheless, even now, though I have done some theory, a lot with Fred Hoyle and with the Burbidges and some independently, my primary interest has been to do enough theoretical work that I could see what were the important things for us to be doing in the laboratory and in particular in the field of nuclear astrophysics nowadays. Thatís a quite different approach to theoretical knowledge in the field, I feel, than one that is perhaps more common. My interest, and I got this from Charlie Iím sure, is, what is it thatís in the theory that will tell us what we can do next in the lab that is significant and relevant? Charlie always had just amazing courage, that, sure, we had things running in the lab and we could have continued to do experiments of the same type or maybe some new nucleus, but he was never interested in that; if there were some new experiment to do, he was perfectly willing to stop all productive research for six months or a year, and -- so weíd be able to do something new. For example, this was why the laboratory, before the war and after, became so well equipped with accelerators. Electrostatic analyzers for the accelerators, which we built ourselves, magnetic spectrometers for analyzing the reaction products of nuclear processes -- all of those things we took time out to build, because you couldnít buy them then.

And when Siegbohn discovered double focusing, we immediately built double focusing magnetic spectrometers here. In fact, the Lauritsen type has been copied all over the world, the ones that use the kidney-shaped coils, because theyíre much more efficient in producing magnetic field over the necessary region than the old spools that one used in early magnetic spectrometer design. Charlie was very much interested always in that, in building new equipment for the lab and keeping the instrumentation in the laboratory up to date, really ahead of its time. As a consequence, as I said a while ago, we built the three Van de Graaffs. Finally, when we decided we needed to go to higher energy than our three million volt home-made Van de Graaff would provide, we did go to the ONR for funds to purchase a tandem accelerator from the High Voltage Engineering Corporation. But Charlie never loved that accelerator in the sense that he did the others, and in fact, I have never used it directly, because of my interest in the astrophysical applications where youíre more interested in low energies, going as low energy as possible. Some of my students have done work down on the tandem, but I have never actually performed any experiments there, and in fact it was not long after the tandem was in operation here that I more or less stopped working actively in the laboratory.

Weiner:

When was that?

Fowler:

The last student that I actually worked with in the laboratory, helping him operate the machine or collect the data, was in 1964. Since then, my students have been pretty much on their own. I talk to them in the office and go in and watch what theyíre doing in the laboratory, but I just havenít had the time to work directly with them all day long as I did from the time I became a faculty member, well, in Ď36, essentially, until 1964. But that works out quite well, it turns out. Of course the students pick up a lot of help and instruction from the other faculty members even though they are considered to be my students. For example, Cary Davids, who is now at the University of Texas, was my student and did his work on the carbon-13 (α, n) reaction under my direction. Nonetheless, he got a lot of help from Professor Barnes, Professor Kavanagh, Professor Tombrello, on how the Van de Graaff operated, how all the auxiliary equipment that he needed could be built and designed. He mainly talked with me about what the experiment was to be. Then when he began to get results, I consulted with him quite frequently on what they meant, what to do next. So in the last eight years thereís been a considerable change just because of my other responsibilities, being on the Naval Research Advisory Committee (NRAC), the National Science Board, Space Science Board, being away -- Iím away from the lab about half the time nowadays.

Weiner:

Including summers in England.

Fowler:

Yes. There was one year when I was away, I had to record it for income tax purposes, I was away something over 180 days.

Weiner:

Well, this desire to respond to the next set of experiments that would be needed for theory in the field, was this partly motivated by a desire to be in a laboratory that was in the forefront of the developing field? Itís perfectly legitimate to want to make an impact as a field is developing. You know that youíve really got the good guys, and you have good advice and a good setup, so then you move into action, with the idea that this perhaps will be more important on the current scene than perhaps pursuing in great detail something that has already been discovered or explored.

Fowler:

Yes, I would say that that was partly the case. Charlie certainly wanted the Kellogg Laboratory to be doing what we now call -- heíd never used the word, but what we now call frontier research. He wanted Kellogg, in those days, the days before the war, to be the top nuclear physics laboratory in the world. But there was a second reason, Iím sure, and itís a very important reason. Charlie became restless if we spent too much time just doing experiments with already existing equipment and analyzing it and writing papers. Really his own personal interest was in designing or constructing new equipment. He really got his major pleasure if in the middle of an experiment something broke, or we needed some new little gadget. He would immediately start scrounging around the lab for a piece of brass or some wire or whatever he needed, and he would go to the lathe and within a very short time produce whatever it was that was needed, like a little vacuum lock or anything, a new target chamber, or a connection from the tube to the magnetic spectrometer. He just loved to do things like that.

I am fairly certain that a strong motivation was the fact that his own personal pleasure came in great measure, not entirely, from actually constructing the equipment that was necessary to do experiments. Now, it did develop that when we worked together, and after I had become a member of the faculty just before the war, even then, Charlie got pretty busy with other things, so that the graduate students we had were all kind of joint graduate students, people like Ev Tomlinson and Bob Becker and John Streib. There was no sharp distinction, this chap is Charlieís student, this chap is Fowlerís student. We worked together pretty much, and I would say that gradually as Charlie became more involved in war work -- you see, he actually left here six months before we picked up the whole lab and took it back to DTM in Washington -- had more close contact with the students than he did. On the other hand, whenever it came to the point where they had to develop some new apparatus, then Charlie was far superior to me in that regard. Theyíd all go talk to him, and he would make a little sketch for them; theyíd go make a finished drawing, Charlie would correct it and give them advice on how to solder this, whether it needed soft soldering or silver soldering, and all the things that he was really very expert at. Then you know, heíd had quite a career in radio --

Weiner:

Yes, a good Danish technical education.

Fowler:

It became clear that electronics was going to play a bigger and bigger role in detector schemes. The role that electronics plays in the physics laboratory is a revolution thatís taken place in my time. When I was a student, we were using cloud chambers and we were using electroscopes. It wasnít until much later, essentially until after the war that all of the new counting systems began to be used. Of course, there were Geiger counters in my time and we used them, but that was just the very start of it.

Weiner:

Another part of it, this concern with apparatus and working on new things, on a human scale, is somewhat different than working on one large instrument, such as a cyclotron for example, which one would refine and develop into various generations. Thatís one way the laboratory didnít go. There was never that large an investment in a single machine which in itself would dominate the laboratory, and where the physics efforts would be centered on it. Of course, a great deal of pleasure can be derived from taking apart a cyclotron and putting it back together again, and improving it in the process.

Fowler:

Well, that isnít entirely true. The X-ray machines that Charlie built were extremely large for their time. You see, at the time that Lawrence was building his cyclotrons, which were quite small, Lauritsen was building million volt X-ray tubes which were 20 feet, 25 feet long, transformers which were 10 to 12 feet high -- had to be housed in a very large room. You see, during the war the, or before the war, this laboratory was this suite of offices along here and on the other floors, but the main part of the laboratory was just one big open vault, and thatís where Charlie had his million volt tube and the transformers, you see. Then we built the three Van de Graaffs, which were quite large. So in terms of his time, the equipment was much larger than anything that youíd find in the Cavendish, for example. But in terms of what we think of now, the very large accelerators and so forth, thatís still another scale. So Charlie was not just interested in little things. He was interested in large equipment, but not on the scale that cyclotrons finally went to, you see.

Weiner:

Thatís part of it. What meant also was that the focus in Berkeley was on the instrument itself, the idea of developing that instrument which had such great potential and could be improved and improved. Your description of his joy in a particular experiment was to design something new, to enable you to get better or more diversified experimental results, with the existing apparatus. In other words, if youíre talking about a program for the laboratory, one of the major programs at Berkeley was to develop cyclotrons. I donít get the feeling that the program here --

Fowler:

-- no, we were not interested in developing Van de Graaffs per se, thatís perfectly true. But nonetheless, there was a progression over a period of time in which these three Van de Graaffs were built, and each one was a vast improvement over the other. Although the last one built was the smallest of the three, it was built to produce very high currents at low voltages, below a million volts, you see, I can show you that. No, I think itís fair to say Charlie was not interested in developing accelerators that would be used by other people. He was more interested in what do we need for our specific purposes here in the Kellogg Lab. Now, on the magnetic spectrometer, the Kellogg or the Lauritsen magnetic spectrometer, there were quite a few of those built, and there Charlie did improve them to the point where they became a very useful general instrument. In fact, youíll find that Hofstadter in building his big magnetic analyzers for electrons for use in conjunction with the Linac at Stanford, pretty much duplicated the Lauritsen design, showing that it could even be scaled to a much larger size than the largest size we built here. But the ones that were built here -- well, I can show you them. Youíd have to kind of find your way around them if they were in this room.

One has at least a 50 centimeter radius of curvature, and must weigh between five and ten tons. Itís a pretty big piece of equipment. But I think the key to the thing was that the equipment always was such that it could be maintained, operated and repaired by faculty or graduate students, you see. Charlie never wanted to get into the point of having a staff of engineers who would be primarily doing the work. He wanted us to do that ourselves. I think that would be the place where he drew the line. Now, itís true that nowadays we have one engineer who does a lot of design work, and we do have tandem operators. But the other machines, the three home-built ones, when a student is assigned a graduate thesis on that machine, when it breaks down heís expected to fix it. Now, he can get some help from the shop men, but he is supposed to actively be there and do the repair job himself, and if he needs some new equipment, a new instrument, heís expected to build it. In fact, one thing that strikes many people very odd, when a graduate student first comes in this lab and wants to do experimental work, his first assignment is in the shops. Heís put through a shop course where he is essentially apprenticed to one of the shop men, and he cannot use the lathe and the drill presses independently until heís satisfied the shop men that he can do so without hurting himself or without hurting the equipment. In many cases boys who came to CalTech wanting to do theory and couldnít quite cut the mustard, finally said, ďAll right, Iíll do experiment.Ē Theyíve never worked at a lathe, theyíve never done anything like that. It may take them three months to go through this shop course. Now, itís a couple of hours a week, maybe three hours a week, but until they really learn shop practice, they just canít be an experimentalist in this lab.

Now, on the other hand, we get some boys who come in and in two weeks they satisfy the shop requirements -- because theyíve had a lot of experience, you see. Then if they havenít had any electronics experience, they get apprenticed to our electronics men. Seems strange in a way perhaps for graduate students to be doing it, but you just canít do experimental physics nowadays without knowing how to use your hands and knowing a lot about experimentation. When I was a graduate student, I was just dumped in the shops and I made mistakes. The shop men get upset with you, so Charlieíd have to go over and say, ďNow, heís just learning, let him try again --Ē We found it was far far better to start them out working with the shop men. Then the shop men feel, ďWell, thatís my boy.Ē He has a lot of sympathy and knows that if the boy makes a mistake, itís partly his fault, you see. So thatís worked out beautifully, and I think many other laboratories do this too, but we started that immediately after the war. Itís been a very successful part of training our graduate students, and many graduate students come back and say, ďIíve forgotten all the nuclear physics you taught me, but I can run the lathe, I remember all that electronics.Ē

Weiner:

On the prewar thing -- was the cyclotron ever considered as a possible instrument for this laboratory in the thirties?

Fowler:

No, because we became very clearly aware that one of our primary interests was in doing excitation curves with as high resolution as possible, and the cyclotron just would not do that in those days. In fact, you can still get a higher resolution with a given energy with the Van de Graaff than you can with a cyclotron, although there have been great improvements made. But also we wanted to be able to vary the energy continuously, and that was quite difficult on the early cyclotrons. There are variable energy cyclotrons now. But it was quite clear around 1938 that what we needed was a Herb type pressure Van de Graaff, and there was never any discussion that I can recall seriously of building a cyclotron here. Now, after the war Charlie pushed for the construction of a synchrotron at CalTech, in order to get CalTech in with the high energy business. But we did not do that. We did not do that. The first man to come here was Robert Langmuir, and then very shortly Robert Bacher came, and Bacher took the leadership in the high energy field.

Weiner:

I want to talk about the prewar stuff. There was a letter exchange between Millikan and Lawrence regarding a rumor that funds would be forthcoming for a cyclotron here, and that the Kellogg people might be interested in that. It never came to pass and Millikan finally said no, thereís no basis for it. That raises a question whether there was any pressure on the part of Millikan for such an instrument or for certain kinds of development which he felt it would be appropriate for the Institute to do. After all --

Fowler:

What period are you talking about?

Weiner:

The thirties, up until the beginning of the war. His overall responsibility after all was to see that the Institute fulfilled its major educational and research purposes, and he would want to see it develop on lots of fronts. I wondered, in carrying out the responsibility, if there was ever any discussion with Lauritsen that you know of regarding the line of research?

Fowler:

I suspect there were discussions. All the discussions were between Lauritsen and Millikan, and I was not in on them. I suspect there were discussions around 1938, because Lauritsen had to go to Millikan for the money to buy the tank for the first Van de Graaff that we built. As I remember, that was something like $3000 which was a lot of money in those days.

Weiner:

$1500.

Fowler:

All right, maybe $1500. Anyhow it was a considerable amount of money, and so I am sure that Lauritsen had to convince Millikan that the direction to go was in the Van de Graaff direction rather than the cyclotron direction.

Weiner:

For precision--

Fowler:

Yes.

Weiner:

That would be interesting, and it could very well be that in the Millikan papers here I can find something on that. I looked in the Millikan-Lauritsen file in the past. I didnít find anything on that.

Fowler:

Yes, I never discussed with Millikan matters of that kind. My discussions with Millikan were numerous, but they were primarily about the results we were getting. When it came down to discussions of the funding and what direction the instrumentation should take, that was primarily between Charlie and Millikan, and frankly I donít think there could have been much argument because by that time, Millikan had great faith in Charlieís ability, and Iím sure Charlie just had to say, ďThis is what Iíd like to do.Ē I canít believe that Millikan would have pressed on him the construction of a cyclotron. But I canít say for sure. I canít, because I was not in on discussions of that kind.

Weiner:

Did Charlie Lauritsen ever put forward a spelled out research plan, a program of research for this laboratory? Itís obvious what the program was and youíve explained it and interpreted it very well, but did he ever explicitly state it in that way -- this is the kind of laboratory we are, these are the kinds of problems weíll take up?

Fowler:

Charlie wrote very little down. In fact, he never wrote anything of that type down that I know of. He did write some things about what the laboratory was to do during the war, but that was primarily directed toward Vann Bush and Tolman in Washington, to justify the rapidly increasing expenditures that were being made once the war got started. But I donít recall seeing any written statement by Charlie of what the general purposes of this lab were.

Weiner:

You donít recall discussions of that?

Fowler:

Well, there were plenty of discussions plenty of discussions, but he never wrote that sort of thing down. And the discussions were never on a very general basis, except just after the war, as I think Iíve said before and has been written down. We did hold discussions, and that was primarily Charlie and myself, about what were we going to do. But neither of us really seriously considered going into the high energy business. We felt we had to talk about it a little bit, but the fact that we had been in low energy with light element nuclear physics before the war dominated our interest, and then this thing that we had learned just before the war started about the astrophysical applications -- it was pretty much an open and shut case. But we did have to make a conscious decision and agree. That I remember was one thing that Charlie always insisted on, that I -- he wanted to know for sure that thatís the way I was committed, and that I still didnít harbor lingering doubts that maybe we should go into high energy physics. That was one characteristic of Charlie. He always wanted a very clearcut understanding of general matters of that kind. But it was never written down. It was always discussions over a gin and tonic and so forth.

Weiner:

It was a small enough group, and resources at least before the war were limited enough. It seems to me that the recognition that Berkeley was developing large scale enterprise must have had something to do with the role carved out here.

Fowler:

Well, I suppose quite frankly we appreciated the fact that at a small school like CalTech, we just couldnít possibly compete. We couldnít compete at that level. There just werenít going to be funds or people. Charlie and I have always felt that CalTech should remain small, that we should not develop something like the Lawrence Radiation Laboratory. Charlie never took the title Director of the Kellogg Radiation Laboratory. We never wanted to form a laboratory of nuclear physics or an institute of nuclear physics. We remained professors of physics at CalTech, and that I think after the war was a very important development. When Bacher came to be head of the physics division, Charlie Lauritsen could very well have said, ďWell, Iím a senior man, Iím going to ask that the Kellogg Radiation Laboratory be divorced from the physics division and be made an institute of nuclear physics.Ē But he never did that. And in fact, that was just anathema to Charlie. He did not, and this is one of the things where he did feel that what Ernie Lawrence was doing at Berkeley wasnít all for the best, setting up a quite separate Radiation Laboratory. Charlie just did not want to do that.

And Iíve always felt that way, and thatís been fairly common here at CalTech. We do have the contrary in the engineering division. At one time they felt it was necessary to make Von Karman Director of the Guggenheim Aeronautical Laboratory, and then Clark Millikan became the Director, and we could see that there was an anomaly there between the Director on the one hand and the head of the engineering division on the other, you see. Not that it ever became a problem, because Clark Millikan and Fred Lindvall were great friends. But Bob Bacher was the boss of all the physics laboratories, and our laboratory was one of the laboratories in the physics division. On the other hand, I know that if Charlie had insisted or had wanted to go the other way, he could very well have done that.

Weiner:

But besides it not being his style, he thought there were positive things to be gained doing it this way? Iím just curious what the philosophy behind this was.

Fowler:

Well, in part Charlie would not have liked all the responsibilities that a director would have had, and he saw that Bacher, who is very good at that as well as being very good at high energy physics, could handle all of those problems very at a small institution like this there was no need for overlapping bureaucracies. One of the key things about CalTech Ė- I think itís appreciated but Iíll say it anyhow -Ė and this was primarily due to Millikan, was that when CalTech was created, Millikan did not set up a lot of departments. He set up six divisions and he lumped physics, mathematics, astronomy and electrical engineering in the one division, with one head. Millikan was nominally the head but actually it was Ernest Watson. Millikan didnít set up a lot of small departments. He just had these six divisions, and we still have that, and I think itís one of the great strengths of the place. Now, you can argue, well, thatís something you can do in a small institution, but I think itís been really the great strength of CalTech, that we have not had a long vertical bureaucratic structure on top of the actual working staffs; between me and Harold Brown there is only one man, thatís Bob Leighton, and thatís true with every other member of the physics department, and astronomy. Now, we have had in recent years to appoint executive officers for each part of this division. Jesse Greenstein is executive officer for astronomy, and he essentially runs astronomy, but thatís a pretty big operation. Nonetheless, Jesse works through with Bob Leighton. Thereís an executive officer for mathematics, I forget who it is at the moment, and John Matthews is the executive officer for physics. Of course, Leightonís much more closely connected with physics. Heís really the boss of what would be the physics department. Matthews is really more concerned with teaching, curriculum and so forth.

Weiner:

Let me ask another question. A few things come to mind. I hope you donít mind me keeping you going back to the thirties. I still want to get into everything else, but I donít think we should get into other things by compromising on things that are interesting in the early period. Just getting back to relations with Berkeley, do you recall any feeling about the relative merits of the results coming out of here and out of Berkeley? It seems to me this lab, as you explained, was very well organized to produce experimental results of interest and to develop the instrumentation for that purpose, and this is somewhat different than the Berkeley approach. Was there any conscious self pride here, any inclination to say, ďWhat weíre doing is adjusting ourselves to experimental questions and coming up with answers, whereas Berkeley, for example, is doing something elseĒ -- justifying your role somewhat?

Fowler:

Well, when I first came here there was a very strong sense of competition with Berkeley and with DTM, thereís no doubt about that. At that time, in a way, this lab reacted to the Cockcroft-Walton discovery, even more rapidly than the other two places did -- but pretty soon, quite soon, the three laboratories were studying the same reactions, and producing the same radioactivities and the same neutron fluxes and the same gamma ray fluxes, so there was a strong competition when I first came here. There was always a race, you see, in PHYS REV letters -- thereíll be a letter from Lauritsen and Crane and either the page before or the page after, one from Lawrence or McMillan or Alvarez. So there was a quite strong sense of competition in those days. But then our interest went in one direction, mainly getting precision cross-sections or excitation curves; Berkeleyís went to letís get higher and higher energy. So I would say even by the start of the war, there was not nearly the sense of competition that there had been in Ď33, Ď34 and Ď35, Ď36, when I was a graduate student.

The two labs had gone off in such different directions that I donít, certainly in 1940 -- of course the war came -- we werenít nearly in a competitive position relative to Berkeley. Charlie quite clearly recognized that there was just no way a place as small as CalTech could go the Berkeley direction. He was perfectly willing to build equipment that was large compared to past standards, but he was not going to go into the construction of very large equipment that required large engineering staff. And I think it was mainly that that kept Charlie from going into high energy physics. He always clearly felt and clearly knew a lot more about designing instrumentations than most engineers, and Charlie didnít suffer arguments from people who thought they knew more than he did very gracefully. He had his ideas how he wanted the thing built, and the engineerís job -- once we got an engineer whom we inherited from the war period -- was largely to get ideas from Charlie and then to carry them out. Then Charlie would really look in great detail into all the designs and the layouts and make sure that it was the way he wanted it, and then build a considerable part of it himself. If a thing was so heavy it had to be done in the shop, still usually Charlie and Tommy and I did a lot of the assembly, to get it together the way Charlie wanted it.

Weiner:

Thatís why Tommy was so useful.

Fowler:

Tommy was -- yes. Tommy, of course, also inherited his fatherís ability with his hands, and there was no doubt that in building equipment, they took the leadership. But I always found some role to play, and I would say that in the later years, a lot of the considerations of what this instrument was to do, were largely mine, because I took a little more interest in the theoretical end of the business than Charlie did. So it was a very interesting team effort, but there was no question that the man who built the equipment in this laboratory was Charlie Lauritsen, with considerable help from Tommy.

Weiner:

You mentioned the impact, the immediate response to the Cockcroft-Walton experiment. Something else occurred while you were here: the discovery of artificial radioactivity, artificially induced radioactivity, and there was a response here. Do you remember whether there were any discussions, excitement about that, ďGee, we should have known that, should have observed that?Ē It occurred just after you arrived.

Fowler:

Yes. All of that occurred so early, or even before I came, that I really wasnít discussing physics very much with Lauritsen and Crane. See, it wasnít until Iíd been here almost a year, maybe a year and a half, that I got my cloud chamber working. I sensed the excitement. I donít think either Dick or Charlie ever took much time to berate themselves because they hadnít made this particular discovery. They felt they were doing pretty exciting things and after all, the first artificial production of neutrons was done in this lab, and that was their big interest. And there were all the problems associated with how to measure neutron fluxes with Charlieís electroscopes, putting paraffin inside them so that neutrons would knock protons out of the paraffin, and all kinds of developments of that kind. But then once the radioactivity was discovered, immediately they started taking the targets out of the target chamber, which they could have done beforehand.

They may very well have seen radioactivity and not known what it was. That could very well have been. But once the Curie-Joliots had done, it, then Crane and Lauritsen got right on the ball and began measuring the production of radioactivity. Charlie did a really beautifully simple experiment. He put a bombarded target of carbon bottom down, on top of one of his electroscopes. The top layer was full of nitrogen-13 which was emitting positrons, and so half of the positrons went through the thin carbon target down into the electroscope, and the other half escaped, and then he -- Now, I must be a little careful. I must be a little careful. The target was thick enough that the positrons that went downward were stopped and gave off annihilation radiation, which was then detected in the electroscope. The positrons that were emitted from the surface just went off into the air and were annihilated at a great distance and werenít counted, and all Charlie did was put another carbon layer on top of the one that had been bombarded and the counting rate immediately doubled, showing what the positrons were doing. So that I always remember was one of the most interesting, very simple experiments, and so convincing, that Charlie did.

Weiner:

Now on the Van de Graaff question, you took sort of field trips at that time, or someone did, I donít know if you were involved -- maybe youíll tell me who did it -- to Minnesota or Wisconsin to see what was going on, is that right?

Fowler:

I went on my honeymoon, that must have been afterwards -- my wife still complains that we visited every Van de Graaff in the country on our honeymoon -- I donít remember. Oh, I had been to Herbís lab. Maybe Tommy went.

Weiner:

He mentioned to me that visits were made and I was wondering if you were involved.

Fowler:

I do remember going to Herbís lab, but I canít tell you whether it was -- it must have been on my honeymoon and that was 1940. That was after we had built the machine. You must remember that Herbís machines were horizontal, and we decided to build vertical machines here, and the internal supporting structure and belt system and everything for the first Van de Graaff, that was pretty much an independent design here. The general idea of putting a belt-driven Van de Graaff into a pressure vessel was certainly Herbís. But we had built an open air Van de Graaff here. In fact Bill McLeanís thesis was partly on the construction of that Van de Graaff in Ď37 or Ď38.

Weiner:

-- Ď39 in this paper --

Fowler:

Well, anyhow, an open air Van de Graaff had been built so that Charlie had ideas of how to support a big hemispherical electrode, and how to have the structure rigid enough so that you could drive the belt, and have a roller at the top, a roller at the bottom, and then the construction of the hoops that went around the insulator columns. That design was carried over when Tommy and I started building the two million volt pressure Van de Graaff. Now, I think itís fair enough to say that Tommy and I did most of that construction. Charlie had a great deal to do with the design, but the actual machining and assembling everything inside was primarily done by Tommy and me, although Charlie would come around and help us and make sure that we were doing things the way he wanted it done, and heíd get inside and check up on what we were doing. But he was pretty busy with other graduate students. The design didnít copy what Herb was doing at all and didnít copy what Van de Graaff was doing at all.

Weiner:

But your interest anyway, for example your Van de Graaff honeymoon, was with the idea of seeing the techniques, seeing what other people were doing.

Fowler:

Thatís right.

Weiner:

When was this?

Fowler:

1940. I was married in 1940.

Weiner:

You already had your installation.

Fowler:

So we already had ours, and that I remember. I just wanted to go around and see what other people were doing. I was mainly interested in what they were using for analyzers and spectrometers and so forth. But also seeing how their Van de Graaffs operated, and learning tricks of the trade like what gasses to use, and what might improve the voltage. See, we used air for a considerable period, until Louis Ridenaur, who graduated here, built the Van de Graaff at Pennsylvania, had a fire in his Van de Graaff. Then we immediately went to nitrogen. But it was that sort of thing.

Weiner:

Where did you go on the trip? Do you recall the major places where one would go to see what was going on?

Fowler:

We were going to Madison, and I remember going to MIT. I went to Pennsylvania. Did Princeton have one? We went to Princeton. Whether Princeton had a Van de Graaff, I donít know.

Weiner:

They had a cyclotron certainly.

Fowler:

Yes, I think I went to see the Princeton cyclotron. The main place was, the main two places were Madison and MIT.

Weiner:

Did you go to the DTM in Washington?

Fowler:

Oh yes, yes, of course, DTM, surely, oh absolutely, yes, yes, yes, right. In fact, oh, and Westinghouse had built one at Pittsburgh. University of Pittsburgh had one.

Weiner:

Thatís where Condon was in charge.

Fowler:

Yes, Condon, yes. I have movies on my honeymoon of Condon doing a hop, skip and jump with that big conical-shaped Van de Graaff that they had at Westinghouse in the background.

Weiner:

Thatís something we should have in the archives -- 8 mm black and white sort of home movie?

Fowler:

Say, letís take a minute offÖ

Weiner:

Weíre resuming after a little break. Letís jump to fission, OK, if thatís all right.

Fowler:

To fission? Why do you want to jump to that, because very little was done on fission here.

Weiner:

Thatís just what I wanted to know. I want to know first of all how you heard of it here. Was it through colleagues, the newspapers? Was there any attempt here to do any kind of immediate experiment of any sort?

Fowler:

Oh, I remember very vaguely about fission. I guess we got the word from Oppenheimer. I would be hard put to say for sure, but I remember Oppie gave some lectures on what was essentially the Bohr-Wheeler theory of fission. At that time, we werenít doing very much with neutrons and didnít have any strong neutron sources, so I frankly canít remember wanting to do anything in that area, and I donít believe Charlie did. We were so busy with the things we were doing ourselves at that time that we did not respond to the fission discovery in the way that many other labs did. There was always the joke, ďWell, thatís heavy element physics, weíre in the business of bombarding light elements, nothing heavier than neon around here.Ē So I never did any experiments in fission and Iím pretty sure that Charlie didnít.

Weiner:

By the time you had the Van de Graaff going, did that really change the pace of research here? You built the instrument because it would give you the precision you wanted and it was quite productive, I assume. Did it change anything about the life of the laboratory, the pace of the research, the involvement of other people in it as well?

Fowler:

Well, of course once the first Van de Graaff was built, then Tommy Lauritsen did his thesis with it, and other students began using it. I would say the major change was that we did get much more involved in the quantitative aspects of nuclear energy levels in the light nuclei. We began to measure the resonance energy and the resonance width and the partial decay widths with considerably greater precision than we had been able to do beforehand, and that changed in many ways the whole character of what was going on in the laboratory. We had been interested in the energy levels of the light nuclei, and had in our previous work discovered quite a few energy levels, had discovered more energy levels than there are, because of errors of measurement and just had statistics, using cloud chambers. But now we began to measure energy levels and energies quite carefully, and in considerable numbers, and that led to our beginning to make these Fay Ajzenberg-Selove energy level diagrams that eventually developed into the Lauritsen and Fay Ajzenberg-Selove series. That all started by our making the Fay Ajzenberg-Selove energy level diagrams for our own uses, and people became interested in them and we began sending copies to other people. Then other people would send us information on what they were doing, what they had found, and Tommy started surveying the literature. Actually two graduate students, Dick Cohen and Bill Hornyak, began keeping separate records of the energy levels. I wouldnít say the pace was changed but it was mainly the character of what we were doing. We became much more quantitative, and then Charlie immediately got interested in building spectrometers and analyzers that had very high resolution. So thatís essentially what the Van de Graaff did for us; the fact that it could produce a stable beam, well resolved in energy and well defined in extent meant that we were able to do things that had just not been possible at all with the old AC tubes.

Weiner:

This nuclear energy level data exchange which we now know, youíre saying this started before the war?

Fowler:

Yes. Just barely.

Weiner:

It would be interesting to find some of that correspondence, some of that information.

Fowler:

Some place in my files I have some of the very early hand drawn energy level diagrams. I must save those, because they are of some historical interest. Let me just look -- when was the first -- very early ones, here -- Earliest one I have here is energy level 3, which was 1950. That was much later. But we had been making energy level diagrams around here very early in the game, just before the war.

Weiner:

Thatís good enough -- it would be nice to find that, I think itís of interest to establish that. When did you go off to the war? When was your first involvement?

Fowler:

Lauritsen and Tolman left here early in 1940 -- well, I canít remember, you can get that. Anyhow I stayed here with the graduate students we had here at that time until the end of 1940, and Becker, Streib and I all took the train to Washington on January 1, 1941, very near the New Year. Three graduate students who werenít quite far enough along were left behind, Ev Tomlinson, Sylvan Rubin, and Charles Shepherd, but when Charlie left earlier he told me, ďNow, youíd better get Becker and Streib to write their theses and stop trying to get any more data, so that if we do get involved, theyíll be available.Ē So we went early in 1941 and I stayed in Washington until August of Ď41. I first worked on proximity fuses. Tommy worked on proximity fuses at the Bureau of Standards. I worked at DTM. Charlie was head of Section L in what was called the Armor Division of the NDRC, of which Tolman was the head. The research was done in Tuveís laboratory and in the one at the Bureau of Standards under Alex Ellett, but they were essentially under Charlie Lauritsenís direction. I first worked on proximity fuses for large bombs to be dropped from one airplane down on another, and as the bomb went by the target airplane, the proximity fuse would trigger. You didnít actually have to hit the target. I worked on photoelectric proximity fuses. There was also a lot of work on radio proximity fuses.

To make a long story short, after we had solved the bomb problem, and had some tests, and the whole thing was pretty much shelved because you couldnít use the photoelectric proximity fuses at night, we did then start attaching these photoelectric proximity fuses to rockets which were provided by the Navy, and we would take our proximity fuses that we had built by hand down to Indianhead, where Dr. Hickman and Colonel Skinner were in charge. Anyhow, we found that the rockets that they were using were quite unreliable and the usual result was that the rocket would either blow up on the launcher and completely demolish our hand-built proximity fuse, or the thing would take off and just plop in the Chesapeake Bay. So Charlie soon decided, and in fact he had been on a trip to England, that what this country really needed was rockets rather than proximity fuses. So he brought us all back here in August of Ď41 and we started the rocket ordnance project here at Cal Tech. Out of that eventually came the Naval Ordnance Test Station, now known as the Naval Weapons Center at China Lake. There was another rocket project here at Cal Tech, that started in jet-assisted takeoff. That was Von Karmenís group and Clark Millikanís. That became JPL. There is a story there. There was a lot of pressure on Charlie and on me in the last year of the war to keep the Cal Tech part of the Naval Ordnance Test Station as part of Cal Tech, and we would just have none of it. We didnít go the way JPL went. Thank God we didnít.

Weiner:

What was your major argument against it?

Fowler:

Well, we just didnít think that a university should be in the business of making rocket ordnance. There was far more reason for going into the developments that JPL represented, although it was also ordnance at that time, but fortunately with the space developments itís gotten out of the military end of it. But we didnít want to continue military work. We felt that we had done the proper thing thing in setting up for the Navy a laboratory that could carry on in the rocket developments, and I think in large measure that has paid off. The Naval Weapons Center, previously the Naval Ordnance Test Station, has been one of their most successful defense laboratories. But anyhow, this actually happened because toward the end of the war, 1943, Robert Oppenheimer asked Charlie to come over to Los Alamos, and pretty soon we were quite heavily involved in engineering work for Los Alamos. We made fuses. We developed a big plant, both at Eaton Canyon and then finally up at China Lake, for the production of the explosives and we made a lot of the pumpkins, the mockups of the big boy that were used in the bombing tests at Westover and Utah. The Chief of Naval Ordnance at that time said -- the camel has his head in the tent, and by the end of Ď43, early Ď44, we were engaged in ďProject CamelĒ for Los Alamos and were committed to gradually phasing Cal Tech out of China Lake, transferring all the people we had up there to civil service. I had most of that to do. It was pretty difficult because a lot of people wanted to stay, wanted to work for Cal Tech and not for Naval civil service, but it went off all right.

Weiner:

Did you ever go to Los Alamos?

Fowler:

Yes. Once Charlie had established this, Tommy and I spent -- oh, Iíd say certainly the last year, just before the bombs were used in Japan. I would say I certainly spent a quarter of my time over there, traveling over there. I spent a couple of months over there learning the business, all the nuclear end, and talking to people about what things were necessary. We got enough involved that the three of us, Charlie and Tommy and I, went to the Trinity Test, which was restricted mainly to people who were pretty closely involved and knew what was going on. But we never got into the nuclear end at all. It was mainly the explosives end and fuses and the metal components. In many ways, I think we duplicated efforts that were being done elsewhere, just so they were sure to have what they needed on time. But we gradually changed our organization here over from working solely on rockets to working on the bomb components.

Weiner:

Digression for a minute -- what was your reaction to the Trinity Test? Did you have a chance to look?

Fowler:

Oh, yes. Yes. It was -- I think the word to use is overwhelming. Just overwhelming. To see that mushroom cloud develop, and the spectacularly beautiful colors that came. It was a very -- just an overwhelming experience, as I remember. And the funny thing was, then you couldnít talk about it with anybody. Couldnít share it. Couldnít share it. It was really something. Iíll never forget that. I can still see that in my mindís eye, that tall column.

Weiner:

What significance did it have other than the esthetic appeal of it? Did it represent for you some new recognitions?

Fowler:

Well, it convinced me, as it did everybody else, that it could be done. You know, there was a pool as to what the kiloton equivalent would be, and I guess Rabi won it. I wasnít in on the pool but I knew about it. I remember very distinctly, because of my experience with all the rocket business previously and the many duds, my feeling was that the best bet was zero, or just the equivalent of the tonnage that was necessary to trigger the thing. The actual explosives there. That was my bet. And I think there were many people who were quite skeptical, who just couldnít believe that this was going to come off. I know that was the way I felt, and so to see the thing go the very first time, that was very, very convincing. Then, of course, it was amazing, we immediately rationalized the conviction that we had gotten from the actual experimental test, by coming to realize that building nuclear bombs wasnít all that difficult, that they were almost certain to work rather than otherwise, you see. That was I think one of the biggest things that everybody came to realize, that these things werenít going to be all that difficult to build and to use.

Weiner:

Did that raise any further implications at the time regarding the war or the use of it?

Fowler:

Well, I frankly think, there was of course the attempt, I guess primarily at Chicago, to get the President, get Truman and Stimson to not use the bomb but to have a trial test. I would say that among those in the know here at Cal Tech and most of the people I knew at Los Alamos, there was a great enthusiasm for using it. Great enthusiasm for using it. I donít think there was really a large number of people in Los Alamos, and I may be unjust in this, but I donít think there were very many who had any qualms about using the thing. The fact that it was their baby and that they had built it -- everyone gets this way. Itís a prime factor I think in military life. You get interested in weapons and then you want to use them. I donít think there was very much opposition at Los Alamos to going ahead with the use of the bomb. But you might get -- I wasnít all that close, but I did know a lot of people there, McMillan, Bacher, Alvarez, Serber, Staub, Oppie himself, Bethe.

Weiner:

Well, thatís an interesting reaction. There are things written of course about the organized part of this, but I donít know if thereís any statistical breakdown.

Fowler:

Right.

Weiner:

You went to the South Pacific in Ď44.

Fowler:

Yes.

Weiner:

What was the occasion?

Fowler:

The War Department decided to send a mission out to study jungle warfare, and one part of that mission was to be the use of rockets in the jungle, and so I was primarily sent out to study the use of rockets in the jungle. Thatís the way it was put. Then there was Billie Mann, who was at that time director of the Washington Zoo, who went out to study jungle clothing, and there was a chap who was the vice president of Standard Oil Company of New Jersey, who was to study jungle transport, how you could get things through the jungle. But actually, the Army wasnít using rockets all that much. The big use was in the Navy, and we actually, although it was the War Department that sponsored this mission, went first of all to Halseyís headquarters in Noumea, and then we went all the way up from New Caledonia to Bougainville, stopping at Guadalcanal and Espiritu Santo, and Ė- but my major contact, until I got to Bougainville, where rockets were being used, there was actually flight-craft equipped with rockets for use as they came into the beach. I have a quite interesting folder on my South Pacific trip, which shows a lot of pictures that I took. Thereís Admiral Halsey there. This was at a test. I did finally go to the Southwest Pacific theatre which was under MacArthur, because this group here under General Heavey had outfitted one of the big DUKWs with rockets, and one of the most exciting trips of my life was when Heavey found out I was in Halseyís area Ė- well, I was up at Bougainville when they found out. They were in New Guinea, and you couldnít go from Bougainville over to New Guinea because Bougainville was under Halsey and New Guinea was under MacArthur Ė- had to go all the way back down to New Caledonia, over to Brisbane.

I was briefed by MacArthurís headquarters for about three or four days in Brisbane, what I was getting into, and it was a damn good thing. Then I went up and these fellows were ready to go into the Hollandia operation. Hereís one of the DUKWs, you see. I donít see a rocket there. Oh, my God, I gave my MacArthur shot to somebody. I donít think I ever got that back. Here were some of the installations on aircraft. These fellows were operating out of the jungle, so thereís some rocket launchers on a TVF Hornet, but I mainly worked with naval ensigns. See the rocket launchers on that landing craft? They were having just a terrible time with them. Hereís some jungle background. This was an aircraft group that were flying rockets and there were some typical Japanese bunkers which were then used for targets later on. The fighting was practically all over on Guadalcanal when I got out there.

Weiner:

Is some of this covered in that book we looked at before? Or is that separate? (Sailors, Scientists and Rockets)

Fowler:

I showed this material to that chap. (Looking at photos, etc.) This is another story. This is Project Vista, which was started, and we had all the trouble. Thatís another very long story. There we all are. It was a chapter of the Project Vista report on the tactical use of atomic weapons that, in large measure, was one of the contributing things to all of Robertís problems, and this is an article that has to do with a transcript of Robertís testimony, and it brings out all the role that this Project Vista which we had here in Ď50 and Ď51 -- I was Scientific Director of it, took the year off, and -- but gosh, I wonder what the devil I did with the picture I gave? But I did give this thing, I loaned the thing to Al Christman who wrote Sailors, Scientists and Rockets, and so a lot of it is in there, but I now remember I loaned my photograph of MacArthur looking at the rockets, which is one of my prizes -- I never got it back. Iíll be darned. I forget who that fellow -- Thor Putnam, I donít even know who he is. I may have sent it back and I didnít -- but this is a complete log of what I did over there and a report. I donít think itís of primary interest. Here was my day to day notebook. (All photos eventually retrieved. W.A.F.)

Weiner:

It should be preserved along with your other papers.

Fowler:

Oh yes. It was a very interesting trip, very exciting trip.

Weiner:

Let me ask, where were you when the war ended?

Fowler:

We were here. We were here.

Weiner:

OK, and when did the discussion start about what would happen at Cal Tech and the readjustment from the war, the whole postwar plan, in terms of the field that you were connected with?

Fowler:

The discussion started immediately after the bombs were dropped on Japan. I remember going over to my backyard with Max Mason and Charlie Lauritsen and a couple of other people to have a drink and discuss what the hell was happening. Right then and there the question arose, ďWell, now what are we going to do next?Ē Fortunately we had had the good sense to already have started the transfer of the Inyokern operation and the operations here to the Navy, so that had gone a long way and had progressed so far that it didnít take us very long to start rehabilitating the lab. The big Van de Graaff tank had been taken out and used as a torpedo launcher at one of our testing ranges. The 2 million volt Van de Graaff tank had been moved over into a corner of the lab, and the small one that we built hadnít been started yet, I guess. So we practically started immediately into putting the Van de Graaffs back into operation. We did not take very long. Then, gee, almost immediately Ike Bowen was made director of Mt. Wilson in Ď46 --

Weiner:

-- I think so.

Fowler:

So it didnít take very long.

Weiner:

Yes, it was Ď46, the dedication was Ď48 at Palomar.

Fowler:

He became director in Ď46, and immediately we started holding these seminars. Quite a few of the Mt. Wilson staff worked on our rocket project, Horace Babcock, Olin Wilson, Robert King, so we knew all of them. When the rocket project started, it was later than the radar project at MIT and all the stuff at Washington, so when we came to look for staff, many of the physicists in the country had already gone to work, and it was the astronomers who were available. So a large part of our staff was made up of people who were working on Mt. Wilson. Horace Babcock worked on sights for the firing of aircraft rockets, built a marvelous little sighting device so that they could have some firing accuracy with rockets fired from aircraft. Olin Wilson worked on fuses, rocket fuses. Robert King worked on rocket fuses. There were probably several others whose names I canít remember now, but anyhow we knew all of them and so it was fairly easy to get these discussions on nuclear physics and astronomy going.

Weiner:

Who initiated the discussions? Was it Bowenís suggestion, or did it just come up?

Fowler:

I think that it started in a discussion between Charlie and myself and Bowen in which we said to Bowen, ďWe realize from Betheís work that there are some astronomical implications of what we were doing before the war and weíd like to follow that up, but we need to know some astronomy.Ē Ikeís reply was, ďWell, why donít I start Friday night seminars in which the Mt. Wilson staff can tell you about stellar structure, stellar evolution, what the word Ďpopulationsí means, so forth and so on, and you can give us a couple of seminars on what Betheís results mean in terms of nuclear physics.Ē So my recollection was that Charlie and I put the question to Ike and he responded in this way.

Weiner:

When had you first heard of Betheís work, the paper was Ď39, I guess?

Fowler:

We knew about it a little earlier because he had a letter in Ď38, so we learned about it in 1938. Then the main paper came out in 1939.

Weiner:

Had you discussed any of this with him, either in correspondence or at Los Alamos?

Fowler:

No. No. Well, wait a minute, this was before Los Alamos.

Weiner:

No, but Iím saying, during the period from the publication of the letter to this postwar decision --

Fowler:

Oh, yes. Yes. Hans Bethe came out here. Hans Bethe came out here just after the war. Heís been here many times, but Hans came out and I distinctly remember, we went up to my wifeís uncleís home up in Sierra Madre, a very lovely place and has a wonderful garden -- in fact, I guess we invited Hans to stay there. Her uncle and aunt were away. I guess Hans and his wife stayed there, yes, and I spent I know part of two or three days discussing with Hans more about this general idea and what we should specifically do in order to improve the quantitative aspects.

Weiner:

This would have been immediately postwar?

Fowler:

Yes. Well, it may have been Ď47, but Hans came out here, and as I remember, we put him up at my wifeís uncleís place. Iíll check with my wife. I remember going up a couple of times and talking with Hans about this, and the main outcome of that was that he impressed on me the uncertainty as to whether it was the proton-proton chain or the carbon nitrogen cycle that served as the main source of energy in the sun, and made it clear that the only way to come to a decision on this was to actually measure all of these cross-sections with considerable precision. Well, we had that general idea anyhow, but Hans made it a very much more specific program.

Weiner:

This was after the seminars had started?

Fowler:

Yes. Yes. The astronomers here taught me and Charlie and the other boys a lot of stellar structure and stellar evolution, but they werenít much help about the nuclear physics. You see, you can make a model of a star in which, without going into any details of the nuclear processes, all the nuclear processes have to do is essentially supply energy at the center thatís equal to the amount of energy being radiated on the surface. So astronomers have been able to do a great deal about stellar structure without paying any attention to nuclear physics. But then when you come down to much more quantitative details, then you have to know about the nuclear physics with considerable precision, and we have in large measure devoted this laboratory since that time to making precision measurements on those reactions that are of some interest in astronomy and astrophysics.

Weiner:

Try, in the short time we have -- itís the beginning of a new story -- to make it a little bit more precise for me -- you mentioned the conversation you had with Charlie Lauritsen and Max Mason after the bomb. Then the next thing we have is your approach to Bowen about wanting to learn more astronomy because you wanted to explore that. At the time you approached Bowen, had that decision been taken? You didnít tell me what was discussed with Charlie Lauritsen and Max Mason. Was that just a general kind of discussion, or within that discussion did this decision occur?

Fowler:

I think the discussion with Mason, and that was just one afternoon, there were many more. Mason had worked very closely with us during the war. He had been head of the Underwater Torpedo Project, which was a separate thing that was administered through the rocket project, but that discussion was mainly, Ďare we going to stick to low energy light element nuclear physics?í I think the decision to do that came first, and then when we began to look around, what do we do specifically? Why donít we specifically concentrate on those reactions among the light elements, that you can produce at low energy, and in particular you want to know, at very low energy, those reactions that are of interest in astronomy. Thatís kind of the way it went, as I remember. Thatís an oversimplification because probably all these things were in the back of our minds, but I distinctly remember that the discussion with Mason was that Charlie and I were saying, ďWe want to go back to what we were doing before the war and we think the thing to do is to get that laboratory going just as soon as possible so we can start taking graduate students and get those Van de Graaffs operating, and weíre not going to start building a new cyclotron.Ē Max agreed thoroughly with that.

Weiner:

Did you have any expectations of changes in the funding pattern?

Fowler:

Well, you must remember that it was at that time that Lauritsen was very instrumental in the setting up of the ONR. He worked with Admiral Conrad, whom weíd known during the war, in establishing the Office of Naval Research. Charlie played a very great role in that, and it was primarily or in part because he realized that things were going to be much more expensive in operating laboratories because of all the developments that had come up in instrumentation during the war, and that he was going to have to get money some place. He realized that every other university that wanted to have a laboratory going was going to need a source of funds, so he spent a lot of time in Washington setting up the ONR. I remember he came home Ď46 or Ď47, must have been Ď46, and said, ďNow, youíve got to write up all this that youíre proposing to do in the form of a proposal, -- a word Iíd never heard of before in my life -- ďto the Office of Naval Research forĒ -- I think it was $100,000, first one, something like that.

Weiner:

Which would have paid for what, reconstructing the Van de Graaffs?

Fowler:

Yes, and one yearís operation. The whole scale of things -- see, before the war, the first year I was here Charlieís budget was $1700, but by 1940 as I recall, exclusive of salaries, the budget was around, in the $10,000 range. But then of course after the war there was also the realization that if the staff was to grow, that there had to be faculty salaries coming out of grants. In fact that was one of the contributions Charlie made. He just did not see how the Institute could grow at all unless, as it got into federally supported research, part of the faculty salaries were paid out of the federally supplied funds. So now, Iím sure many other people contributed to that idea, but I know that Charlie played a very important significant role in that, and he did that. I was back here. I was back here at home. Tommy and I, our job was to get this lab operating, and as I say, one time Charlie came back and said, ďNow you gotta write a proposal.Ē ďWhatís a proposal?Ē

Weiner:

Did you keep a copy of that?

Fowler:

Iím sure we have it Ė-

Weiner:

-- sort of prospectus for what happened since then, fascinating thing to look at.

Fowler:

Yes, Iím sure we have it someplace. Iím sure we have the very first.

Weiner:

Make a note to look it up. I really think it would be very interesting. Do you think this is a good point to stop? We have to stop any minute, the question is, do you think this is as good a point as any, because itís the beginning of the next period essentially.

Fowler:

Yes, I guess we could stop, because the whole business of our work subsequently in nuclear astrophysics is yet to come, and maybe weíll just have to put that off to a later date.

Weiner:

Can we agree between us that weíll do it?

Fowler:

Oh yes, Iíd be very much interested in doing that, yes. It would have to be next fall.

Weiner:

All right. By that time letís hope you can have this back and have a chance to check it.

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