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Interview of Philip Hauge Abelson by Amy Crumpton on 2002 June 26,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Education in chemistry and physics at Washington State University in early 1930s; graduate studies and work on cyclotron under E. O. Lawrence at University of California, Berkeley from 1935-1939; investigations into products of neutron irradiation of uranium; identification of transuranic element 93 with Edwin McMillan; scientific activities at the Department of Terrestrial Magnetism at Carnegie Institution of Washington; work on enrichment of uranium for nuclear submarine project at the Naval Research Laboratory; describes information channels between scientists and government officials during World War II and his perspective on the use of the atomic bomb; continued work at Carnegie by investigating biosynthesis of E. coli using radioactive tracers; as director of Carnegie’s Geophysical Laboratory conducted organic geochemical investigations of amino acid decay in Mercenaria mercenaria; co-editor of the Journal of Geophysical Research; reflections of his editorship of Science.
This is Amy Crumpton interviewing Dr. Philip Abelson on June 26, 2002. It is our second session. Dr. Abelson, we had stopped last time, it was about 1940. You had just finished your PhD and had come to Washington where you were recruited to work at the Carnegie Institution. Then you had gone back to Berkeley briefly to do some experiments on the cyclotron to discover neptunium?
The chemical properties of neptunium.
The chemical properties of neptunium. So, that’s I think about where we left off. I guess one question I have for you first was, the job at Carnegie, how did you hear about this or how were you recruited for that position as a scientist at Carnegie?
As it turns out, a publication had something to do with matters.
This was your first Physical Review article? Or the second one?
Well, I had a bunch of little pieces in it. But, one was given maximum display because it was the first one in the volume. When it was noted by Harvard, Washington University of St. Louis and with the Carnegie people, they all decided they wanted to talk with me which was a very desirable state.
Exactly. That’s a wonderful state to be in. So, they took to actively trying to recruit you?
And it turned out the most active of the recruiters was a group from the Carnegie Institution of Washington, in part because they had received authorization to build a 60 inch cyclotron here in northwest Washington to supply radioactive tracers for laboratories up and down the east coast. It was desirable then to have a chemist who also had some experience with the cyclotron at Berkeley to be part of the crowd. They had a small group, but they had conducted world class research in nuclear physics.
This is the Department of Terrestrial Magnetism at Carnegie?
Yes, Merle Tuve. He and Larry Hafstad had done the first proton-proton scattering that established the fact that at close distances two proton, instead of repelling each other, actually were attracting each other. It’s a different world when you get that close.
And that was an experiment that was recognized by the physics community as being a very important experiment. In going to that small place, I was going to a place that had a small number of staff members, but one in which high quality work was known to have come from. Well, in the previous talk, we had me going back, in 1940, to Berkeley for five days to examine the properties of neptunium, which I did. In the course of five days, I did develop knowledge about the properties, and also the matter was written up. So, at least two items, one in the Physical Review, July 1 issue in 1939, I can look at and have pride in them because I was cooking on the front burner. You know you do that a few times in your life.
Right, it all falls together. It’s very satisfying. Yeah.
It all falls together. Right, well on the way back from Berkeley to Washington in May 1940, the Germans were successfully invading France. It was clear, at least one had a deep hunch, that there was going to be a world war two and that one way or another the United States was going to be in it. While I continued to work to order parts for the cyclotron that we were building, my real thoughts began to be on what could I do about the new future. So, I decided that I would look into the mechanisms for separating isotopes. Because it appeared that probably if you could separate enough of the uranium isotope U-235, you could build a bomb.
Now when you started thinking about this were you in touch with other physicists or chemists that were doing similar kinds of things?
Well, it turns out that in some of my behavior I’m a loner and in some of my behavior I’m a joiner. On this occasion, I was a loner. I mean I had this hunch but I wasn’t going to be noisy about it because I was employed to do something else.
I see. So you were running your own experiments late at night or something?
What I did, first of all I reviewed the literature about methods of separating isotopes. I went to the Library of Congress and found that there’d been success in some separations but they were separations involving elements such as lithium and carbon. But, finally I found an article by two Germans in which they had been able to separate isotopes of zinc to a degree, not perfectly, but to a degree and they had done in aqueous solution and they had used what was called liquid thermal diffusion to do it. I decided this was for me because I would see what I could do about liquid thermal diffusion. So, I more or less duplicated, the apparatus they had used. I didn't have a mechanism for doing isotope analysis of zinc isotopes, but there was someone at the Bureau of Standards who could measure isotope separation in potassium. So, I conducted an experiment with some potassium salt in solution and found I could verify that this method gave rise to a partial separation of the potassium. The next step was to try a solution of uranium salt. When I did this, what did I find in the bottom of my column, but a dirty mess!Somehow the process involving soluble uranium salt in water led to chemical changes in the uranium itself. I had some kind of uranium oxide at the bottom of that column. It told me that if I was going to use this method I had to employ a uranium compound that had no water associated with it. I looked in the various textbooks and I found that one of the substances that had been made was a uranium hexafluoride, UF-6. But, it had been made by reacting fluorine with a uranium metal. Well, so I looked further at the chemistry and I found out that one could prepare a UF-4 in aqueous solution and, in fact, you could use very cheap raw materials you didn’t have to use the metal which was expensive. So, you could make the UF-4, you could dry it, get rid of any water, and then add the fluorine to it, add two fluorines to it to make UF-6. At that time, of course, only a few people in the world made fluorine gas and they did it using electrolysis. I knew how to machine things, I could make equipment, so I made myself a fluorine generator.
Now how did you, the resources at Carnegie were fairly liberal so that you could sort of use thing there...
Well, they had a machine shop.
Did you have to ask permission to do these things or could you just kind of play with it and get what you need and justify it later?
Well, we had a lot freedom. Nobody was asking us to report half hour by half hour what we were doing. Not only that, but I worked more than the eight hours so I could go in and get the deed done while nobody was looking.
So, you created this machine to.
So, I created a device for producing this very reactive fluorine gas. Well, then I also decided that, aha!, this UF-6 was going to be very reactive. I studied its behavior with various metals at elevated temperatures to see whether they could withstand it, because if you couldn’t contain it without it reacting with the metal you couldn’t do business. But, I found that nickel was very resistant and that even at temperatures as high as 500 degrees Centigrade the nickel would withstand the UF-6. I also found, however, that most metal that you could obtain was made by processes that involved grease or whatever, so that there were thin films. But, that if I treated them with the fluorine ahead of time, the fluorine would take care of any, it would destroy any organic matter or whatever that would later react. It was more reactive than the UF-6 itself, so I could get rid of any substance that would break down the UF-6. With all that done, I was ready to proceed to build a larger column to make an effort to see if I could get an isotope change in the UF-6. Considering the fact that earlier people were trying to separate lithium 6 and 7 and had just done a few milligrams of that, to be thinking of separating hundreds of grams of uranium from 235 to 238 was quite ambitious. But, you have to take your chances sometimes in this world. One of the things that happened was that it became noised around that I had conducted an experiment with the uranium solution, that I’d had uranium in the Department of Terrestrial Magnetism. Their experiments in nuclear physics that were conducted, were very delicate, they needed to have marvelous statistics and they couldn’t afford to have around alpha particle emitters and that fellow Abelson couldn’t be depended on!
So, you were banished from the physics department basically?
So, Merle Tuve sought to get me transferred elsewhere.
He approached Lyman J. Briggs, who was director of the Bureau of Standards which was then located on Connecticut Avenue. So, facilities were made available for me elsewhere.
I see. So, you were still technically a staff member in the Department of Terrestrial Magnetism, just your lab was relocated to the Bureau of Standards?
Yes, and indeed when I needed to have anything machined or whatever I would come back to home base.
So, this was about 1941 or 42?
Well, it may have been 1941. I do have the date that I ran my first experiment seeking isotope separation of uranium with the equipment at the Bureau of Standards in April 1941.
And, of course, when you start out trying to use a piece of equipment you don’t know what the best dimensions of it are, what spacing, and so you make a guess. I made a guess and it turned out that I was fortunate in being able to get isotope measurement made by Alfred Neir who was the country’s leading expert in mass spectrometry at that time. He was at the University of Minnesota. There was some very small, but detectable difference between the isotope concentration at the top and the bottom of my twelve foot column. At that time, Lyman J. Briggs had been appointed to be head of the so-called uranium committee.
And on that committee was, again, Merle Tuve because of his stature. There was a representative of the Naval Research Laboratory and the man at the Naval Research Laboratory was eager to get enriched uranium because he had in mind that ultimately there would be a nuclear submarine. He was already thinking about it. He’d begun thinking about it back in 1939 and part of the reason he was thinking about it was that radar was capable of detecting submarines when they surfaced. On the other hand, he could visualize that if you had a nuclear powered submarine it could cruise under water practically undetectable for long periods of time. It was the kind of project that a naval research laboratory ought to be engaged in. So, when he heard, and being on the committee he was informed, that I had obtained that small separation and he knew that he had far better sources of high pressure steam available at the Naval Research Laboratory than were present at the Bureau of Standards. His name was Ross Gunn.
Ross Gunn. Now this committee, who was sponsoring this committee?
That was the U.S. That was the federal, that committee had been appointed by President Roosevelt.
So, in June 1941, down to the Naval Research Laboratory I went.
You just moved from place to place.
They had machine shops that I could utilize. Since Ross Gunn was much interested in the project, I had a priority within the laboratory and I could get machine work done easily. And then ultimately, I was able to get a small but effective source of high pressure steam that enabled me to conduct experiments at temperatures as high as 286 degrees Centigrade. There followed a succession of finding out the optimum spacing, the optimum conditions for running the equipment. There also followed then a succession of more and more columns being built and, ultimately, there was authorized three hundred columns to be run at high pressure steam at the Naval Boiler and Turbine Laboratory in Philadelphia. This was in about 1943. And then about this time, General Groves, head of the Manhattan District, was informed about what was happening.
Okay. So, he didn’t know what was going on?
He wouldn’t have known.
Did you have particular kinds of security clearances and that sort of thing to working on this project? Were you allowed to speak with your colleagues at Carnegie about what you were doing?
Oh, I didn’t tell them any of this. Well, the one person who knew about it was Merle Tuve himself, but he wouldn’t have told anybody else. So, as far as the rest of the colleagues were concerned, I simply disappeared. I wouldn’t tell them anything.
I see. Okay. So, Groves found out about what was going on and wanted to get your expertise or wanted more information?
Well, there follows a kind of an interesting story. It turned out, before I went to NRL, I had been advising Briggs on nuclear physics matters because he had nobody in his outfit. Nuclear physics was brand new and the bureau wasn’t supporting nuclear physics though he was the head official government man for uranium research. While I was there, whenever he had a question, he would turn to me and I would consider the matter. I even visited a few places on his behalf. But, of course, as soon as I went to the Naval Research Laboratory that was off. Well, he got an advisor that was a distinguished theoretical physicist who was far more competent to help him than I was. But, among theorists they have their own knowledge channels and so, this fellow knew about what was going on under Robert Oppenheimer and he then knew what I was doing. He also knew the status of other outfits that were trying to enrich uranium. So, he let Oppenheimer know what I was doing.
Who was this person, this advisor?
Gregory Breit, okay.
Well, now this was in 1943, Groves had visited but nothing much had come of it. So, one day, I forget who ordered me to do it, but I was ordered to appear at the Warner Theater at 8 p.m. on a certain day, go up on the balcony, and that I would be approached by a naval person, who would give me a certain codeword, and then I was to hand him a two-page summary on where we were on the separation of the isotopes. So, I went as instructed.
And the Warner Theater, this is right down here in D.C. on 12th Street, I think.
Yep, not far from where we are. This was very clandestine.
That was the one really clandestine thing that I was into.
Now, before that you worked at the Naval Research Labs, the little bit of work that you did before that, did you publish anything? Was anything put into the literature?
Not about this.
Not about the separation.
Oh, no, no.
You knew this was a delicate enough issue...
By that time, you didn’t, publication had stopped.
Okay. Publication on nuclear physics in general, or...?
And what other kinds of related fields, such as chemistry?
Whenever there was a possible military application, everything was ended.
Right. And you knew this from reading the literature and knowing what was going on. Was there any other sorts of, I won’t say censures, but people telling, you know your mentors or others saying, you know that this research should probably not be in the literature yet, or the journals themselves not wanting to publish it?
Well, I don’t remember all the mechanisms but I’m sure the editors of journals were informed and so on. So that word really got around very quickly.
So it was getting around word of mouth by people who just knew what was going on.
And, you know, there would be staff meetings of places and at the staff meeting there would be five minutes devoted to saying keep your mouth shut boys.
Really? Now did you all have particular kinds of clearances by then? I know you were still...
Oh, in the end they had all that kind of clearance and so on.
But at first it was mostly just the community saying you need to be quiet. It wasn’t formal.
Well, by that time, I forget when we got into the war, but the moment we got into the war then you had to have a clearance and all that stuff.
Right. Now, did you visit or work at any point in Los Alamos?
No, the closest I got to it was Oak Ridge.
Okay. Okay. But, did you meet with any of these other scientists, would they come to D.C. to talk about your work.
Well, of course, when General Groves came he brought some advisors. But, there was again the number of people that were in contact with me was limited.
Right. So, you were still working pretty much solo at the Naval Research Labs at this time. That was, throughout the war you were at the Naval Research Lab?
I was not eager to expand my circle of acquaintances. On the other hand, when it was a matter of policy, of my policy, what do I do next, then...
You would seek out.
I would seek. I wouldn’t make any more positive statements than I had to. The positive statements might be made in a memo to the head of our laboratory, Ross Gunn, about what the opportunities were and the alternatives in the way of decisions. But, it was interaction, as I said, with a limited number of people.
Did you attend any meetings like for society meetings at all?
No didn’t attend any society meetings during the war.
This is interesting, because, I guess, during that time many people, or some people, consider the classification and strictures on information flow to may have been detrimental to scientific advances. But, from your case, it seems as though you worked very well this way because you had a lot resources at your disposal and you had key people that you could contact when you needed to or who could give you information when you asked.
Yes. No, it was best to keep that information fairly tight and with a real need to know obvious before you inform and people that had been cleared, because there’s no use blabbing to a bunch of German spies.
Right. And at that time, it was not clear that there weren’t some among us, I suppose.
Well, I will bet you that there were a bunch of them. I don’t know them by name or whatever. Incidentally, one of the people that I’ve talked to since has kept emphasizing that one of the key people who was actually an associate of Albert Einstein was a spy for the Russians.
Really? Interesting. It was a very strange time, I’m assuming. And, obviously, you never spoke about what you did with your wife or family.
Oh, no, no, no, no. No it was no use. How was that going to benefit the war effort?
Right, right. Now did you feel isolated at all? Or was this your preferred mode of work?
No, I didn’t feel isolated.
You were getting some interesting results.
I knew what I wanted to do.
I knew what I could do and I knew what experiments I ought to be performing.
So, you had gotten to the point where you had built, you had been working in Philadelphia on one of the experiments to create the nuclear submarines...
We started, the objective would be that if the war went on and it was desirable to make the nuclear reactor for the submarine we would be able to separate the isotopes and make a nuclear reactor.
And that experiment there was successful then in Philadelphia?
What happened was then that by that time at Oak Ridge the mass spectrometer method of separating isotopes was working. Ernest Lawrence had caused a huge number of pretty effective mass spectrometers to be made that could separate U-235 and U-238. But, it turned out that if the feed into his machines could be made more rich in U-235 then the product would be enhanced both as to quantity and quality. And that was really the reason why that meeting at the Warner Theater was set up. What happened then was that the naval person went out to Los Alamos and informed Oppenheimer and Oppenheimer informed General Groves and General Groves and some of his associates came to the Naval Research Laboratory and then came to Philadelphia to observe what we were building. They got blueprints for what we were building and then General Groves made the edict that they were to build a Chinese copy of what we had in Oak Ridge. But, with more of them. 2,100 of them.
Okay. My gosh. Now did you go down there? You’d said that you’d gone down there, is that when you started?
Then in due course, I was migrating around...
To sort of advise...
I was at Oak Ridge, and then I was at NRL, and then to Philadelphia. I was making...
I was making the rounds.
To advise and help troubleshoot or whatever.
Yeah, see what was going on and perhaps suggest some new experiment. Well, most of our production then at Philadelphia was simply used as a feed for Oak Ridge. But, we also did set up to see if we could enrich the uranium so it would be suitable for a reactor for a submarine. In other words, we did the pilot plant work. That if the next step needed to be to get enriched uranium for a nuclear reactor we knew how to do it.
And had shown feasibility.
Right. And this is, you wrote the large report with Gunn on this and gave it to, this was by 1947 or something that you all had finished your work on feasibility?
In the end, there were two reports, basically. One report was the report on the work at Philadelphia. You know, what you could do and what we had achieved and so on. The other report came after the war, I got authorization to visit research that was being done with nuclear reactors. So, I conducted personally some experiments with nuclear reactors. And, incidentally we were a bit, shall we say, a little careless with them until one day, I guess it was in, oh, maybe January or February of ‘46, a person at Los Alamos was doing an experiment and somehow the way he was doing it he had two assemblages of enriched uranium which were being brought together and the thing that he had holding them apart slipped. He got a super reactor, he got irradiated, and a day later he was dead. When that occurred the rules changed all of a sudden.
Right. So, before you were using sort of minimal protection on yourselves?
Yeah. No, you know, these were.
You were truly handling things, I mean, you were not using...
You did the thing with reasonable care, so nothing happened, nothing happened to me. But, as I say, once this accident occurred, then all of a sudden all kinds of restrictions.
Right, were put in place.
You know, that’s human nature, that’s the bureaucracy.
Right. And also because the scale was getting larger, too, I’m assuming, so there were more places that mistakes could be made.
But, I learned enough about the reactors that I went back to my naval research laboratory. In the meantime, a veteran submariner, who’d actually been close to Japan, you know, been in some close dangerous encounters, but now his duty had changed and he was a liaison submarine officer, he was eager to have submarines that would not be so detectable. What is more, well, one thing he did was to procure a copy, this was now after August.
1945. And there had been a team of U.S. people that had gone and they had gotten some of the latest technology from the Germans and they had blueprints of the latest best German submarines and, they were, of course, diesel propelled. But, I had the latest information about a nuclear reactor for submarines. So, we were encouraged to make a feasibility study of this. We replaced the diesel on their equipment with a nuclear reactor and some shielding and, of course, chose to do it in a simple way, just by replacing weight for weight. In March ‘46, I submitted a report on the feasibility study for a nuclear submarine.
So, I want to ask your reactions to the events of August of 1945. There’s been, obviously a lot, a lot of work done since in retrospect on the dropping of the atomic bomb and the concern that many scientists, or many physicists in particular, had after the dropping of the bomb with its use and the new uses of atomic energy. I was wondering if had any thoughts you’d like to share with me on that or if you had shared any of their concerns at the time about what we were getting ourselves into with this new technology.
Well, as it turned out, one of the people that I knew had actually been in Siberia and knew where they were studying about landing U.S. troops there, preparatory for the invasion of Japan. It was his feeling that if the invasion of Japan had occurred there would have been very massive U.S. casualties and there would, of course, been also massive additional Japanese casualties. So, from the standpoint of casualties overall my impression was that there were less casualties as it happened than might have happened had conventional warfare had gone on. There’s no way that you can guarantee what is going to happen in future when a new technology is released, whether it’s going to be beneficial to a lot of people or whether it’s going to be harmful. My guess, even today, would be that if it hadn’t been for the restraint of the Cold War, the past history is that every generation, on average, every generation there’s some damn big war. I mean, people are out to kill each other for stupid reasons.
Unfortunately, that seems to be the case. Right, right.
So, while I’m, to a degree, nervous about the present situation, because there are just too many ways of people killing each other today. There are those who are hell bent to do it.
Right. And unfortunately, some of them have atomic weaponry and other kinds of high-powered weaponry at their disposal.
They have bio-terrorism and so on. Well, just stopping for a minute on bio-terrorism, if that were done skillfully, people wouldn’t realize that that had happened until a week or ten days after the thing had been released and then all of a sudden there would be mass panic. There would actually be more casualties and more problems from the mass panic than...
The attack itself. Yes, I’ve read that, too.
Yeah. So, now if there were a crude bomb that distributed a bunch of radioactivity, well the next day after it’d been exploded and then within a day it would be clear what the limits of the radiation were and what it was and so on. So, the rest of the country would go on, life without, so what’s new, what’s wrong?
Right. Well, the years immediately preceding the war, there were a number of physicists and other scientists calling for test bans and control on atomic energy. Were you in any way involved in any of those kinds of discussions or interested in what they were doing?
I didn’t. That was for them, I was busy about something else.
Okay. You moved on to a new, you were still working on nuclear submarines, right?
Well, no I finished that. As soon as I finished that report I became a biophysicist.
Okay, and you were still at the Naval Research Lab?
No, when I finished that report in a couple of months I was back at the Carnegie Institution of Washington doing tracer research of one kind or another. Ultimately, about two years later, I was doing biosynthesis in Escherichia coli.
Right. That was very interesting work that you did on that. You and your colleagues who worked on that created a textbook that was pretty much the definitive work, I guess still is.
Well, it was good piece of work.
So, you went back to Carnegie and then you basically started to create new fields of science, is what I understand.
I did, first of all, microbiology and then later on I was director of the Geophysical Laboratory, and then I did amino acid in clams and then paleontological specimens. I did, also, studies of how petroleum was created and studies of preservation of organic matter way back half a billion years.
Now, when you were working on all these different projects, did your sort of modus operandi stay essentially the same, did you work mostly by yourself or did you only seek out colleagues when you knew you had a question that needed an answer?
As it turned out, I had some colleagues who were a bit more expert in instrumentation, the development of instrumentation, than I was, and so I was using their instruments.
So did you have a, at any point, did you ever have a conflict as to what kind of scientist you were? I mean, because in science there are so many different professional societies that one would belong to and go to particular kinds of meetings if you’re a physicist or a chemist and so forth. Did you try to attend many kinds of things or did you basically just use the resources and the people you had at Carnegie?
Well, I belong and still belong to half a dozen scientific societies and get their publications, but it’s been a long time since I’ve gone to one of their meetings. I find that a publication may have represented two or three days tops at a meeting. I can skim through and identify what I think is the most significant piece, most interesting thing. So, I feel that I operate myself more efficiently playing it by my own way.
Now, when you gave talks about what you were doing did you go to particular society meetings or particular kinds of forums to deliver what you had learned?
Well, it turns out that while I was editor of Science I was asked to give quite a few talks. They were not in general given to society meetings, they were given at university seminars.
So, the work you did at Carnegie was primarily published and it wasn’t so much that you were going out and giving talks on it, you were doing your work and publishing it.
So, you by then had been published in how many kinds of journals? You were all over the place...
Quite, quite a few.
Physics and biology journals, chemistry journals and everything. Well, we’ve come to, I think, a fairly good stopping point. We’ve gotten through the war years and you’re at Carnegie. And, I guess, we’ll pick up when you become director and president of Carnegie and, I guess, when you become editor of Science, that’ll probably be our most important discussion next time.
Well, there was some miscellaneous things and I’ll give thought as to what I should chat about.
But, it won’t have the whammy of some of those earlier things.
Oh, I think there’s gonna be plenty of whammy in what else you have to say, you have a very long distinguished career. Okay, well, I think that should be enough for today and I will meet you next week.