The Manhattan Project

Ed Hammel's Interview

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Ed Hammel was a young physicist at Princeton University when he signed on to work for the Manhattan Project. Stationed at Los Alamos, he became involved with the site’s production of plutonium. He stayed at Los Alamos after the war and became involved in the hydrogen bomb program. In this interview, he discusses the early efforts to design the hydrogen bomb, the scientific innovations he and his colleagues developed at LANL, and why he decided not to work on the Ivy Mike shot.
Manhattan Project Location(s): 
Date of Interview: 
01/09/1985
Location of the Interview: 
Los Alamos
Collections: 
Transcript: 

Martin Sherwin: The work must have been sort of very frustrating for a while, before that [Stanislaus] Ulam-[Edward] Teller breakthrough [on the hydrogen bomb].

Ed Hammel: Well, sure. There was— 

Sherwin: What were you doing at that time?

Hammel: At that point, I continued with having this group in charge of properties of plutonium. But one of the things that we were very interested in was the low temperature properties, the specific heat specifically, of plutonium.

It’s of some considerable interest, I think, that at the start of Los Alamos—you perhaps know, or may or may not—that there was an intent, “Let’s go right to the Super [bomb].” And for that reason, the very first operational building that was built out here was the low temperature laboratory. Earl Long, who had gotten his PhD I think at Berkeley, came out here.

There were only two hydrogen liquefiers, I think, in the country, or three or something like that, at that time. One of them was out there, and Earl was recruited and worked at Columbia. It was realized that if Los Alamos was going to put a bomb together and they were going to go the Super route, they needed a low temperature laboratory capable of making of large quantities of liquid hydrogen. So therefore, in February, I think, of ’44—so that was from April of ’43—a building and an air liquefier and a hydrogen liquefier were all constructed. At that time, they were, I think, the biggest ones in the world.

By 19 February ’44, when that thing was finished, it became apparent that the fission bomb was going to be harder than they thought, and the thing was abandoned. It was turned over and run once and mothballed. Earl Long was put in charge of the shop for the rest of the war.

Sherwin: Would it be fair to say then that Teller is right in saying that when he was brought out here, he was told that he could work on the hydrogen bomb?

Hammel: Probably so, because there was a famous conversation in the Columbia University faculty club, or at least walking to it, with [Enrico] Fermi and Teller, in which this whole notion that—people thought, they realized then, that if you could ignite the thing with a fission bomb, you’re in business, and that ought to be easy.

So I think it is correct. I think that’s in the historical stuff—I think I’ve got a copy of that here—at the very beginning. The whole cryogenic activities here, it started with the intent of moving in that direction right off the bat. But it was stopped in February of ’44. Probably a little bit before that, but they decided to finish building the thing just in case. And then it was mothballed.

The point of that business was that that existed, and in about ’46—I guess it was ’46—we were interested in doing some low temperature work on plutonium. At that point, this building was still in the old Tech Area, hadn’t been opened or used ever since. We asked permission to start a low-temperature physics laboratory. 

At that point, for many years after that, I just got plain interested in low-temperature physics and spent the rest, almost twenty-five years in that area. We came again with two other new materials. One was the isotype of helium, helium-3, which we liquefied here for the first time in the world. That was helium-3, and tritium. The first in large amounts of tritium appeared here in connection with the hydrogen bomb project, and tritium decays to helium-3.  So for years, right after the war, one of the very exciting aspects of low-temperature physics was, first of all—I have to back up.

Helium-4, ordinary helium, undergoes a remarkable transition at 2.17 degrees Kelvin and changes into something called a superfluid. It has absolutely remarkable properties, no viscosity. And, it turns out to consist—that transition is [0:06:00] now, now been demonstrated to consist of essentially a macroscopic quantum mechanical state. You know, in the sense of the electrons, if you like, going around. That’s a quantum mechanical stationary state. But people only knew that it existed in very, very tiny things. Helium, in a cupful of it, is like that. Just like superconductivity, it’s the analog.

The question was, theoretically, why was that important, or why did it occur. The argument was that the reason that helium-4, a mass 4, ordinary helium behaved as a quantum fluid was because there were an even number of elementary particles in the helium-4 nucleus, two neutrons and two protons. Under those circumstances, it obeyed a certain kind of quantum statistics called Bose-Einstein statistics, which did go through some kind of a curious condensation.

If that were so—there really was some problems. It wasn’t exact, but this was the idea. If that were so, if helium-3, with only three, one neutron and two protons, behaved the same way as helium-4, that was the wrong theoretical explanation if they behaved differently, which it did.

So there were efforts going on from the end of the war onward to somehow or other concentrate the very, very small, one part in 10 million, of helium-3 in ordinary helium to get enough to make this test. All of a sudden, when tritium in 1946 and ’47 became available, we got helium-3—I won’t say coming out our ears, but we had more than anybody else.

So that experiment of trying to cool it down, liquefy it, determine its properties, and see whether it behaved was a very, very exciting thing, and in some sense put Los Alamos on the map. Everything you did was exciting with new things. The tritium, and tritium was another. Nobody had ever had tritium before.

Sherwin: When you said it became available, how did it become available?

Hammel: Because it was for the hydrogen bomb project.

Sherwin: In ’46?

Hammel: In ’46? There were some precursors. I don’t know how close I can come. I can’t say it was the hydrogen bomb project per se. But there were some precursors, if you wanted to put it, and that’s the best way of putting it. Maybe it was ’47. I know we liquefied it in ’48.

Sherwin: Now, was Teller pushing this? Was he here?

Hammel: Yeah, yes, yes, yes, yes, he was involved in—

Sherwin: Teller? 

Teller: Oh, sure, yeah, because he was very interested in all. This was really fundamental science and incidentally, it’s another illustration of what you said. That was good physics, exciting physics. We didn’t have to ask anybody, “Could we do it?” Everybody was interested in all of it.

Sherwin: Now, I spoke to a lot of people who are in the GAC [General Advisory Committee of the Atomic Energy Commission], [Lee] DuBridge especially. He was the clearest in this regard. He said, “Every time we were approached”—GAC really comes into operation in January of ’47—“Every time we were approached with a superbomb proposal, idea,” he said, “It just kept looking worse.” Not that it was impossible, because certainly in the report that the GAC made in October of 1949, when they came [inaudible] going for hydrogen—

Hammel: Yes.

Sherwin: They said in their report, if we have a crash program like the Manhattan Project and we put all the money and talent into it, there’s a 50/50 chance we can have a hydrogen bomb in five years. And indeed, that’s what they got. But there was a lot of reasons why it might not, in fact, be possible. But Du Bridge’s view was that it just didn’t look as it progressed that it was moving in a hopeful direction.

Hammel: That’s not true. You probably know more about classification than I do, I don’t know exactly. I can tell you one thing: very early on, there was established here something, you probably heard about: the Family Committee. I was a member. It was a big committee. Johnny von Neumann came and John Wheeler. They were visited and spent a lot time. Teller. I think [Eugene] Wigner was out here. The Family Committee met almost every week, reviewing progress. It was sort of organized right after, in January of ’50, that the decision was made.

It was about January ’50, we went on a six-day week here, and the Family Committee was established to look at all [0:12:00] aspects of it. Low-temperature physics was involved from day one in this whole operation, and it was one of the pains in the neck. The sequence of tests that were then organized were the step-wise sort of things to see whether indeed you could ignite the stuff. So those were all done.

Sherwin: That’s in January ’50. But what’s happening between ’46, let’s say, and ’48 and a half, the beginning of ’49 now? Tritium has been developed?

Hammel: Tritium sure as heck was being made. I guess it was still then Savannah River? That wasn’t in business then, was it? I don’t think so. I think we were getting it from Hanford. Since I’m not a bomb weaponeer, I was excited about using it for helium-3.

Maybe I’ve got the dates wrong in the following sense, because we’ve got enough to liquefy of helium-3 in October of ’48, early October, 17th, I guess. Something like that. At the same time—my daughter’s birthday.

Sherwin: You’re sure it was ’48? 

Hammel: Yeah. It was ’48. That’s when we first had enough helium-3 to liquefy. To get that, the people out in radiochemistry group were milking the tritium that we had here. It was also true there was enough tritium, because we were in a race with the people from the Argonne Laboratory who were trying to be also the first to liquefy helium-3. We beat them by a couple of weeks. So there was enough tritium being produced at that point for them, and there was enough for us.

It’s conceivable that it could have started to appear in ’48, early in ’48. But people must have started to try to make it in ’47, at least, because the piles had to be properly loaded to do that. There’s no other use for it, in a sort of sense, than at least to be thinking of this. Besides, right after the war—I’d have to look it up—there was F Division here, which was Fermi’s division, which was looking at a Super and Teller was there. I remember right after the war, I went over and thought, “I would like to work on this,” and remember talking with them.

So there was work, there was thinking. I don’t believe there was any experimental work here on the Super as such at all. There was no concerted effort until we got the word, “Go ahead.” But there sure as hell was a lot of theoretical calculations going on, absolutely. I suspect there may have been physics experiments. By the time we got into it, in the ‘50s or so, then we had to start looking at some of the low-temperature properties of tritium, of liquid tritium, things like that. But that was all sort of connected with the mainline program.

The critically important shot is one that I’ve been told is still not declassified, the so-called George shot. You know about that? That was the time we first saw the thermonuclear action go. And we were in it up to our necks.

Sherwin: Are you familiar with Herbert York, The Advisors?

Hammel: Oh, yeah, right, yeah. That’s right. He talked about that there. In fact, he was on the tower when I was on the tower.

Sherwin: What do you think of that book [The Advisors]?

Hammel: Gosh. Been a long time since I looked at it.

Sherwin: But you don’t recall that there was anything fundamentally wrong?

Hammel: Oh, no, no.

Sherwin: I think it’s a—

Hammel: He’s a totally honest guy.

Sherwin: Well, you can even be wrong if you’re honest.

Hammel: Yeah, I know. But even so, I think he was certainly well plugged in and moved very fast in the Livermore operation. But I guess Livermore hadn’t even started when some of that stuff—that came right after that, didn’t it?

Sherwin: Livermore was about ’52.

Hammel: Oh, yeah. Because, I know he was out there on that shot, too. Within hours after that George shot, I remember being in one of the dormitories or something, or someplace out there with a tower, and he was already on the back of the envelope figuring out what he was going to do then.

After the Mike shot, why then all hell broke loose in terms of trying to figure out how to do this with so-called “wet weapons.” There was a lot of work done. It would’ve been a god-awful mess, but I don’t think that anybody was that worried about the fact that it couldn’t not be done for the military from there on in.

Well, there’s another little piece of the thing. It just is perhaps useful to use it to calibrate everything that I’m saying. That is that we had participated through from 1950—when was the Mike shot? Was it ’54? It was, wasn’t it?

Sherwin: 1952?

Hammel: No, I don’t think so. I’ve got it in here someplace. But that was the Bikini shot, that was the full eight, whatever megatons.

Sherwin: Oh, the full one, the one that got away, fifteen megatons.

Hammel: Something like that, yeah. It was the one which resulted in those Japanese fishermen.

What happened was that after the George shot, where we saw 14 MeV neutrons for the first time, that was the end of the Family Committee. [Norris] Bradbury decided to establish a new organization here, which he called DIRX, Director’s Experimental, something like that. Marshall Holloway was the guy from here who was put in charge of the thing. Marshall, I think, had been a division leader in M Division, or something like that. At least, it was a weapons physics division.

What happened right away, was that Marshall—Earl Long, this guy that I said during the war had built this thing, had gone back to Chicago. He was working on the helium-3 like we were too, but he was doing it in Chicago. Marshall decided that he knew—I didn’t know him very well, and he probably didn’t know me. But we had the only show in town, so to speak, and had really, I thought, did enough, the whole damn group had done an outstanding job in making the Greenhouse series and making it work. So we thoroughly expected that we were going to be involved in a comparable fashion and started out that way in the Mike shot, in the initial preparations and building models of the whole business and planning and everything else.

And one fine day, I was told that Marshall was going to bring Earl Long back to run the cryogenics program. I was furious. I went up to Bradbury and said I thought it was a hell of a way of treating somebody that had done what our whole group had done. As far as I was concerned, he could have Earl Long or me, but not both. I was damned if I was going to work for Earl. I guess they got together. Bradbury talked with Marshall and Marshall held firm and brought Earl here. So I said, “Thanks a lot. I’ll help you where I can, but I don’t want any part of it.”

So the Mike shot went along certainly without me. But the whole group was at their service, and my sort of system guy head was put in charge then. He and most of the guys, actually, went over and participated. Most of my group did it, but I didn’t. I was really ticked off.

I know what happened to the Family Committee there pretty accurately, but Mike was out. Maybe it was stupid, but I didn’t particularly like Earl anyhow. I was damned if I was going to work for him since he hadn’t been through all the other stuff. So that was that little piece.

There are also some minutes of the ALAS meetings and things like that, when I got to worry about it. ALAS, the Association of Los Alamos Scientists, I think I was the last chairman of it. I don’t think I drove it into the ground. It was connected in part with these [inaudible], that what we saw was [Andrey] Vyshinsky and [Andrei] Gromyko and people were eager and hopeful.

As soon as it seemed as though, well, the United States would give a little bit, there would be another whole slew of things you had to do. I think people gradually just got disillusioned and in 1949, when they [the USSR] fired their first bomb, I think the feeling of many people here was, “Fool me once, but you guys were just stalling for time. All of these objections were not for real.”

Hammel: What happened was that I think it was in September, about mid-September or October, that the Association of Los Alamos Scientists, ALAS—in the very beginning, the people who were involved in the thing were the big wheels. It’s worthwhile, for whatever it’s worth, my recollections were there were sort of three groups of people here in Los Alamos. There were the real wheels. There weren’t very many of those, but there were a lot.

Sherwin: That would be Oppenheimer?

Hammel: Yeah, and [Hans] Bethe and [Robert] Bacher, and Teller, and Viki Weisskopf, and [Richard] Feynman. They either had Nobel Prizes before or after, almost all of them.

Some of the ones you probably don’t know or may not have heard of. There was Joe Kennedy, who died very shortly after the war. He was one of Seaborg’s students, and he was one of the co-discoverers with Seaborg and Art Wahl, who also came here, of plutonium. Joe headed up the chemistry division here. And then Cyril Smith from MIT, who you probably do know, came and was co-division leader of the chemistry. That’s where I worked, in the chemistry, on the plutonium end of things.

But going back to the sort of hierarchy, there were the, if you like, the “wheels.” The next echelon were, I would say, people a little bit ahead of me. I got my degree—actually, I finished up at Princeton in ’41, but that was only two years after I got there. Hugh Taylor, who was the head of the department, wasn’t about to bounce somebody out of the place in two years. So I stayed on in ’41 and started working on a piece of the Manhattan project at Princeton in May of ’41.

Sherwin: Was that part of [Robert] Wilson’s group, or [Henry DeWolf] Smyth’s group?

Hammel: No, no, neither one. Because what was going on at the same time, it was the Wilson/Smyth operation and I think [Walker] Bleakney on mass spectroscopy was down in the physics department, too. But in the chemistry department, there was first of all [Harold] Urey at Columbia, who had the heavy water project, originally. They were having lots and lots of trouble there. It turned out a good friend of him was Hugh Taylor at Princeton, who was eventually the dean in the graduate school at Princeton, but he was head of the chemistry department. Taylor had been working in the ‘30s with Urey on some of the chemical properties of deuterium, and he was also an expert in catalysis.

There was formed at Princeton a group of about, well, John Turkevich and myself, and a guy by the name of Louis Rampino and so on. It was relatively small. But we started to try to working out a way to essentially separate tonnage amounts of deuterium. There was also going on in the chemistry department, under the analytical chemists, work on analysis of uranium. They didn’t have any plutonium. So those were the two things that were going on in the chemistry department.

We didn’t have a hell of a lot of contact, if any, between the people in the chemistry department and the people in the physics department. As a matter of fact, when we came out here because in 1944, my wife had been having a lot of trouble with sinus, and we had heard about a part of the project out in the Southwest someplace. I talked to Taylor and he said, “Well, go on down to the physics department and talk with Smyth.”

So I made an appointment, came to his office and walked in and said, “I’ve been working up with Dr. Taylor at the chemistry, and I would like very much to get transferred to the project in the Southwest.” I didn’t know where it was exactly.

He looked at me, and he says, “How the hell did you find out about that?” But it worked out, and I came out here in June of ’44.

It started in ’41, that heavy water project. We finished it up in Trail of British Columbia, where they built a big tonnage plant for that thing. Then that was done, and we started working on the barrier problem for Oak Ridge. I think if I’d stayed there, I probably would have ended up at Oak Ridge, because many of the guys did. But I came out here and worked on the purification of plutonium.

Getting back to the original end of things, there were people like myself who had finished, essentially, their formal education, had their degree, but that we didn’t have any place to go to. You see, Bacher and all the rest came from someplace. So right after the war, they couldn’t wait to get back again. But the rest of us were, as I say, the next level down, and either we’d bounced maybe a job or two, but there was that. Then there was another group, whose work had been interrupted at graduate school, and they, of course, pulled out to go.

After the war what happened was, the big shots, some of them pulled out within weeks, others stayed six months to the beginning of the next semester, and then the rest left. Then the young people left. So there were a bunch of us who were going to just stay on. I didn’t know what we were going to do. I think very few people thought they wanted to stay, but nevertheless, we did. I think it was that group and Bradbury that sort of kept the place rolling until it sort of came to and decided what was going to happen. That’s that piece.

My point, the reason I got off on that was looking at this ALAS. Oppenheimer never joined the thing, but almost everybody else were involved. Phil Morrison—

Sherwin: Was Oppenheimer out of here when this got going?

Hammel: No, he was still here. This was number two. Yeah, October 30th. On the second, for example, this was the famous Oppie speech, November 2nd.

Sherwin: 2nd, yes.

Hammel: Which you’ve seen, got it?

Sherwin: I have a copy of the speech. 

Hammel: Okay. Yeah, I had to get this thing from Chicago. Maybe I got the reference from your book, I don’t know.

Sherwin: Yes, that’s right, I do have a reference in the book, and I think I also got it at Chicago.

Hammel: Yeah, because all I knew was that it was the most moving talk I think I’d ever heard in my life.

Sherwin: Could you tell me about it? I have not found anyone who was there, who really remembers it. Why was it moving?

Hammel: This is just wild reminiscing, but I think it’s related in the following sense, a feeling of a group of people who were here during the war. There was another thing which is relevant, and that is all of us in this middle group that I’m talking about, were very young, just married. We had babies galore. You read about the story of the people who went to Santa Fe and had the dinners at Mrs. [Edith] Warner’s down at the bottom of the Hill, all that stuff. We weren’t in that, involved in that at all. We were taking care of babies, mostly. That was item one.

The second thing was, for those of us in the Manhattan Project in general toward the very end, the entire Chicago group, the entire people that were left at Chicago for the most part, and the people at Columbia had essentially finished their work. Everything was fed to Los Alamos, and they had the time to ruminate about some of the larger issues. That’s why the frank operations and everything, that all emanated from Chicago. I know less about what happened at Columbia.

Here, in the summer, if you like, of ’45, the T Division people were pretty much finished. There were some last minute things, but the theoreticists were behaving like and thinking about other issues, and pretty much most of the physics of it. The people who were working their tails off were the people who were making the cotton-picking thing. During that, we had first of all the business of collecting of everything, just enough to make the first test.

Sherwin: You and [George] Kistiakowsky?

Hammel: No, I was with Kennedy and Smith, in the chemistry and metallurgy end of things. The guy that just died yesterday, Richard Baker, he and I shared a desk across the hall from each other. The sequence was that the plutonium came to Los Alamos as a compound. It was purified in our analytical group in that building, and then delivered to Baker as a compound. Baker then reduced it to the metal. And he would get a sort of pancake of plutonium about this big.

Sherwin: That’s about nine inches long?

Hammel: No, it was smaller than that. I don’t remember.

Sherwin: An inch square? Two inches square?

Hammel: They were round. I’d say about it was about two inches in diameter and maybe a half-inch high. These were the buttons, and then we had to take enough of those to essentially make one-half of the bomb. I got all of those things, cleaned them up, put them together, remelted them and cast them essentially into a close a configuration as we could. Vacuum remelt to essentially purify, evaporate all the stuff that could have possibly evaporated from them, and then cleaned the blooming thing up after, get all the scab from the crucibles off of it. Then it would be delivered to people who pressed it.

This was what we were doing. My recollection, and I’m sure it’s right; we worked almost around the clock, because to get the stuff ready for Trinity was really scraping the bottom of the barrel. It came in very fast that spring, eventually.

Then as soon as the Trinity shot was ready, the Nagasaki shot was ready, and after that, while that was going on and people were working on the end of it. The people who were in the metallurgy end of things, and I think Kistiakowsky and the explosives, they were working their cotton-picking tails off.

That means then that it was only a couple of times, I would guess, that you sort of sat in the end of hall and thought a little bit. I think we had all made up our mind that this was important, it was essential to do, no question about that. But in contrast to a lot of other people, the larger implications of the whole business, I think, didn’t come until afterwards. Then they came, by and large, very rapidly, and they were in many ways, the whole Federation of Atomic Scientists, ALAS and so on.

The answer to Oppie was, Oppie put all this in words, a magnificent formulation. He obviously had been thinking about it. He had been participating and arguing, I think, about some of these other things. I would be embroidering, because my memory on these things is miserable anyhow. But I certainly remember it was one of the most moving talks, by a person who was clearly absolutely adored by everybody here.

Sherwin: I guess everybody turned out.

Hammel: Yeah. Everybody was there. Either he’d left and come back or—

Sherwin: He did.

Hammel: He did. Anyhow, after the meeting, Viki Weisskopf presented Oppie with a gift from the members of the project in appreciation of his service as a project director.

By January ’46, you see, a lot of the people had left and let’s see. By June 15th, I was on the executive committee [of ALAS]. I sure never would have made it in the beginning. Then later on I was chairman of it. I think I was the last chairman. John Manley was involved in the thing. Rod Spence, Maury Shapiro, who’s at the Naval Research Lab, Phil Morrison, [David] Hawkins and so on, Jane Hall.

Sherwin: Did Morrison stay here?

Hammel: Yeah.

Sherwin: Until he went to Cornell?

Hammel: I think, yes, I’m sure he did. He was here longer than a lot of the other people.

Sherwin: Was Louis Rosen in there, too?

Hammel: Louis wasn’t, I don’t think so. There were some people who just would have absolutely nothing to do with this whole business, but not many, I don’t think.

Sherwin: This is quite a collection. What are these?

Hammel: You remember the question I asked you about [Bernard] Baruch, the group report, afterwards?

Sherwin: Yes.

Hammel: This is one of the reasons, because this was Baruch essentially presenting the plan to the United Nations. “The reaction of the Los Alamos has been in general favorable to the approach taken by Bernard Baruch.” And everybody was saying, “Thank God we’re finally doing something or other.” First of all is the inconsistency in everything I’ve read, that it sounded as though we’re giving it—but, apparently, an awful lot of people in Washington who had no intention of anything like that. It was window dressing, in a sense. It doesn’t come through. Look at all of the New York Times when we were just keeping records of everything, and everybody was thinking, “It’s just great.”

Sherwin: Yeah. Well, I think at the time, you know, and the way it looked publicly there was, “Thank God we’re doing it,” just like—

Hammel: That’s right.

Sherwin: “We’re so happy that [George] Schulz and Gromyko”—

Hammel: Yes, yeah.

Sherwin: “Have made some kind of a sensible agreement, although we can all see that there may be problems with it. But the first step has been taken.” I think that’s the same view that people had.

Hammel: That was present.

Sherwin: Well, there may be some problems, which—

Hammel: Yeah, “We’ll work them out.”

Sherwin: Yeah, “We’ll work it out.” The problem is when you start looking at the documents and you start finding out what the inside people said to each other, as opposed to what they were saying publicly.

Hammel: Yeah, then you begin to have—

Sherwin: It was a different story. Oppenheimer, for example, resigned, just said he didn’t have the time to work with it. It wasn’t because he didn’t have the time to work it.

Hammel: He just saw it going—

Sherwin: He found, first Baruch to be just an impossible ego.

Hammel: Yeah, he was an intensely conceited guy.

Sherwin: Can you imagine Oppenheimer and Baruch in the same room, with a limited amount of air? I mean, each one was sucking all the air out.

Hammel: I think that was one of the reasons for the Strauss to-do. Oppenheimer couldn’t stand him either.

Sherwin: I think Strauss had more of a problem with him. I don’t think Oppenheimer felt threatened in any way by Strauss, but Strauss felt threatened by Oppenheimer. I think that that was a different problem than the one between Oppenheimer and Baruch. I think at least on Oppenheimer’s part, there simply a dislike. He thought that it was putting this, the most important issue of the moment, without doubt in his mind, in the hands of this financier, was not the way to go. It was very disappointing.

Hammel: Yeah. Well, it certainly is true that these worries or anything—it would have been inappropriate at the time to surface any of the stuff, because people were hoping. The other part of it, I think I can say—I mentioned there were those of us who didn’t have any special place to go and it was a nice place, and, “Well, let’s see.” But as this thing began to unfold, there was also a feeling that “No matter what happens, there’s got to be some place in the world that will be on top of this whole new element.”

There was many, six or eight months or so, maybe more, where many of us looked forward to becoming a part of that of that organization, if you like, an international island or something like that. That was another little piece of this whole business that certainly the people who were involved in the ALAS operation were concerned about.

Sherwin: There’s no question that if international control of atomic energy had become a fact of life, it would have taken a lot of physicists—

Hammel: Sure.

Sherwin: To run it.

Hammel: That’s right, and from the weapons end of the thing, too, there wasn’t a concern that if the various nations of the world agreed to this, and the verification and all the stuff went along with it. That was fine. But this was so blooming new in 1945 that one certainly did not understand all of even the theoretical aspects of it. And supposing that somebody could figure out how to make one pea-sized, or something like that, the argument was that there was lots of work more to do. We just did during the war the absolute minimum amount of investigation of properties of everything to just do that job, the physicists and the chemists.

And another thing that was very exciting: after the war, we sort of reorganized and I ended up in charge of a group that had a responsibility. The assignment was essentially, determine the physical properties of the new element plutonium. All the rest, the magnetic properties, the low temperature, the specific heat, the things that we didn’t need to know to make the bomb. I would argue that there have been few people in history that have been given a brand new element on the face of the earth and say, “Hey, look, fellows, what can you find?” Almost every stone you turn over is exciting, new and different.

That was one of the nice things of staying on here since, first of all, there were so many connections in the outside world with Los Alamos. There was a constant stream in those early days, especially during the summer, of people who hadn’t possibly maybe been involved during the war. Fred Seitz, for example, was here in the summer. We would work with Fred, and he would try to teach us some of the other things that we didn’t know and he knew lots about. So, the summer times were absolutely glorious in those first few years. Then also many of the old-timers kept coming back, too. So it was an exciting place.

Sherwin: Yeah, Lou Rosen said this morning that it was the most incredible experience, that for many, many, many years, if you needed money to do something, you just said you needed money.

Hammel: That’s right.

Sherwin: And you just got, “How much?”

Hammel: Yeah, that was it.

Sherwin: And you got it. And whatever it was you wanted to investigate, you investigated it. You got the facilities to do it. It was, as he said, sort of the best place to do—

Hammel: It was fantastic, it really was. There was so unutterably little paperwork to go with it.

Sherwin: That’s a change.

Hammel: Yeah, it was essentially—I came across something last night, it was a project authorization form. It was about this long, but you signed it and wrote what you were going to do, and then tell how much money you need. If it looked good, “Yeah, sure.”

Sherwin: Now, you must have been here, too, when Oppenheimer came back in ’66.

Hammel: Yes.

Sherwin: Was that reminiscent of the November ’45?

Hammel: No. He was sick by that time, I think, or not, at least—

Sherwin: Yeah, he died six month later.

Hammel: He did, yeah. From the times we saw him after—I’m not sure whether he did come back, but I think on television or something like that. I think that the people who knew him here during the war felt that that that whole clearance business just seemed to break a man, and I don’t know how it could other than that. Because, to my way of thinking, like Geraldine Ferraro and [John] Zaccaro. If they’ve got somebody famous who thinks a little mistake is 10,000 times worse than what everybody else does all the time, and it’s a big deal, and it’s outrageous. You probably know more about it than I do, but it must have been a terrible thing for him to go through.

Sherwin: I think it was [Isador I.] Rabi who said, “He’s broken.” [Inaudible] I think that that’s true. Now, I don’t think it would have broken someone who had a different kind of personality. But I’m not sure exactly what to say about that, in that a person who was tenaciously independent and very, very much his own person in terms of the environment I think could have used it as a platform. Because he certainly had a very sympathetic audience out there from which to fight back and to push the views that he was being really raked over the coals for, for uttering [inaudible] 

Hammel: But he obviously wasn’t that kind of a person. The reaction—I’ll bet you got it from everybody that knew him. God knows, I didn’t know him. I think I probably maybe talked to him once or something like when I was there during the war, but we saw him at the colloquia. He was there all the time, and this was one of the wonderful things about this place, no secrets.  Joe Blow down the bottom of the line and we all sat together every Tuesday night at the colloquia.

So one gets a feeling for how he behaves. I know I’ll overdramatize, but I think everybody had the feeling here, he was a noble human being. A sensitive, caring human being who I don’t think he had an ounce of ambition it seemed in it. He was selected to do this job, and I think he gave it everything he had. He was concerned—and it was legendary as you probably know, too— that he worried about making sure that the laundry for the baby diapers were taken care of as well, if that would come to his attention, too. And, you know, it got done.

There was no advertisement. You heard about it word-of-mouth, because it was so small. But, oh, it had gotten straightened out. So, the esprit de corps was just out of this world.

Sherwin: Now, at the colloquia, were they dominated by the big shots?

Hammel: No, I don’t think so.

Sherwin: The people like you—

Hammel: I think if you had something to contribute, you did. I don’t remember any sort of putdowns or anything like that. But on the other hand, I don’t want to give the impression that we ran wild. You knew who else was there, and unless you’re really pretty doggone sure, but there was no, nothing ever. Because there were certain things that the younger people knew, being closer to it, that they didn’t. So it was all welcomed, all open, and very, very informal.

I remember the first one I went to. [Niels] Bohr was here. I told you, I couldn’t understand him!

Sherwin: [Inaudible]

Hammel: Yeah, I think so. He had a funny “wh” that seemed to get in the middle of every word. It was very, very low, and I think that it’s like reading technical French or German, if you know what he’s talking about, it isn’t half bad.

But the other impression I had that was really puzzling, or surprising, was coming from Princeton and going to that first colloquium. The accents were—I didn’t think I was in the United States anymore! [Laughter] So this was, I think, certainly interesting.

Sherwin: Do you remember what Bohr was—well, you didn’t even know what he was talking about.

Hammel: No. Coming from one part of the project, which was pretty compartmentalized, to another place where there was a lot of catching up to do. There was at the very beginning in April of ’43, there was a set of—I don’t think they’ve been declassified—but there were the Los Alamos seminars. [Edward] Condon was here for a bit, [inaudible], and Serber and the rest of them. I think Serber wrote them up. But those were sort of required reading then for all the characters that came later. But that was a way of pulling the entire operation together, for people who were coming from all over.

Sherwin: Kind of like a handbook?

Hammel: Yeah.

Sherwin: Do you remember any of the other colloquia? Do you remember that meeting that I think was initiated by Robert Wilson about the question of the Gadget for the postwar period? There was one meeting in which, you know, sort of an implication that the bomb was discussed, sometime in the spring of 1945.

Hammel: Spring of ’45?

Sherwin: Yes. And Oppenheimer spoke on it and then there was discussion about what role the scientists at Los Alamos—

Hammel: Would play. Yeah, I think I heard about that. I heard about that, and I’m almost sure that I probably was not there. Again, that’s one of the things that depends upon where you were working and what you were doing. They say they were open.

I remember on this remelting end of things, why, I’d call up my boss, who was Eric Jette from Columbia, and it would be 11:00. “We’re going to make a melt. You want to come over?”

Sherwin: Now. When you say “melt,” you were taking—

Hammel: They had been putting them together, heating them up in the vacuum and casting them into the right amount and shape. Then if something happened, you have to do it all over again. Mess.

Sherwin: If an impurity got in?

Hammel: Not an impurity, but something, the way we did it, I guess it’s not classified. We had a doubled crucible with a hole in the bottom. And the bottom of the crucible was a shape that you wanted, [0:36:00] and then you’d melt it at the top, and then eventually—

Sherwin: [inaudible] [0:36:03].

Hammel: No, no, no. It was in a vacuum with a high frequency, just like the microwave.

Sherwin: How hot was it? 

Hammel: The melting point is around 630 or something like that, I think. So it wasn’t too hot. But, nevertheless, one had to alloy the thing. There wasn’t one pure metal. It turned out that every once in a while you get a bum one, so these were very critical things. If it got messed up at that stage of the game, well, you had to go all the way back to recovery, chemically, go back to Baker, all the way through the thing.

It did happen from time to time, because you had no control over it after you put them in as best you can, make sure they’re clean as ought to be. But sometimes it just wouldn’t go through, it’d be too low in weight or something. So that’s why I think there were undoubtedly ones that I missed, but not because I wanted to.

Sherwin: Okay. Were you at the Trinity?

Hammel: No, no. We were making the next one.

Sherwin: You were making the next one?

Hammel: Right.

Sherwin: So you were making the real one?

Hammel: Yeah, yeah.

Sherwin: And then there was one after that, that was available on the 21st or something like that?

Hammel: Yeah. You haven’t met Dick Kosh, yet, have you?

Sherwin: Dick Kosh? No.

Hammel: He was one of the physicists, little older than I am. He was working on the Van der Graaf. He came from Wisconsin, and eventually, he became a group leader like everybody who hung around here. Then he became head of the Physics Division for about ten or twelve years. When [Harold] Agnew became director here, he asked him to be an assistant director in charge of research. Then I ended up as an assistant director with him, finally, before I retired. He got to be associate director.

Anyhow, we’re very good friends, but that’s the place where our recollections are completely different. My recollection is that after we got rid of the Nagasaki stuff, we started right to work on numbers five and six. They were hemispheric, essentially. So you had one and two were the Trinity, three and four were the other, and five and six were going to be the next one.

He said, “There weren’t any more.”

I said, “There sure as hell were!”

Sherwin: No, well, there was, I mean—

Hammel: You know that yourself?

Sherwin: Yeah, absolutely.

Hammel: Okay.

Sherwin: I mean, there are lots of documents that talk about the next one, which was supposed to be ready on the 26th, but they moved it up to about the 21st.

Hammel: Okay.

Sherwin: And [President Harry] Truman says, “Nobody drops another one without my say-so.”

[Norman] Ramsey was writing back from the islands that, “We want to leave.”

He was being told, “You can’t leave until we’re sure everything’s over.”

Hammel: Okay. I see.

Sherwin: But, you’re right, there was—

Hammel: My recollection was that we didn’t stop, we kept right on going, trying to put the rest of the thing together.

Sherwin: It probably stopped after that.

Hammel: Yeah, I don’t remember there was another one.

Sherwin: Because I’ve gotten ahold of a document that talks about the number of weapons between 1945 and 1948, and there were two for ’45. Now, it must be two after Hiroshima and Nagasaki.

Hammel: That’s probably right.

Sherwin: Because we know of this third one, so there might have been a fourth one.

Hammel: Okay.

Sherwin: And then it says for 1945—

Hammel: Fourth complete unit.

Sherwin: Well, the units were never put together. They had the bomb, and they had the core.

Hammel: Okay.

Sherwin: I don’t remember whether they were both implosion, or one was implosion and one was gun-type.

Hammel: I don’t think there was—

Sherwin: There was one more gun-type.

Hammel: Was there one more done?

Sherwin: Somewhere between ’45 and ’48. I don’t remember where it goes.

Hammel: Okay. Because that went out pretty soon. That, I know.

Sherwin: I know, and they knew it was [inaudible].  And there were nine in ’46.

Hammel: Oh, okay.

Sherwin: Thirteen in—

Hammel: That’s all declassified now?

Sherwin: An, there were fifty in ’48, and that’s where the exact numbers stop.

Hammel: I see.

Sherwin: So what happens is a very slight [inaudible,] then in ’48 it goes way up, and I’m sure in ’49 it really began to escalate.

Hammel: Yeah.

Sherwin: Probably 100.

Hammel: Well, I know that there was one thing that interfered right after the war, and one would have to go back and look at the books to see what exactly happened. But there was a C Shop fire. You know about that?

Sherwin: C Shop fire?

Hammel: That was in—

Sherwin: The letter “C”?

Hammel: Yeah. We had A, we had a B Shop and then there was, later, I guess it was about in late ’44 or early ’45, a very, very big machine shop was built in the tech area called C Shop to handle really big stuff. One night, I think it was in the spring of ’45, that thing caught fire.

Sherwin: Oh, before the war ended?

Hammel: Yeah. That scared the pants off absolutely everybody. The argument being, that if it had ever gotten over to the D Building where we were working with the plutonium, it would have been a real disaster.

So there was initiated a plan to essentially remove all of the plutonium work from the Tech Area and put it out at DP Site, which is down one of the—you know, it’s right across from the airport. You can see it as you drive out, just to the right.

Sherwin: So that was the perimeter of Los Alamos?

Hammel: Yeah, right.

Sherwin: At the guard gate?

Hammel: Yeah, but the guard gate and that tower where Philomena is, that’s further down. This is just about opposite the office at the beginning of the airport, and most of the airport was on the right.

Sherwin: So, that’s probably, what, a mile and a half—

Hammel: In fact, those towers, that thing you said, water tower, that was moved out to DP Site, because after that, they got worried, “What if that thing went up?”

Sherwin: I’m just trying to locate , mile or two from the—

Hammel: Tech Area.

Sherwin: From the Los Alamos—

Hammel: Inn?

Sherwin: Not the inn, what was it called?

Hammel: The Tech Area, the old Tech Area?

Sherwin: The [Fuller] Lodge.

Hammel: The lodge, sure. It’s probably about two miles from it.

So, before the war started, that new plutonium handling facility was all being planned. That was another thing that was driving us all up the wall, to try to do the planning for that thing, at the same time everything else was—

Sherwin: You said before the war started, you mean before—

Hammel: Before it ended, rather. So it was prompted by the C Shop fire. My recollection was that some preliminary work must have gotten started in about August of ’44 or something, just when everything else was happening.

That’s why I think as soon as the war was over, I have a suspicion we shut down everything, all plutonium work in D Building, the old D Building, and then spent that fall essentially moving everything out there,  because by that time it was finished.

That’s, again, my recollection. We made one, two, three, four, five, six, and then stopped, because it was all over, and then no more in town until we got that thing ready.