George Cowan: It’s weighted so heavily in favor—not in favor of—but the emphasis on number one Los Alamos, and then Oak Ridge, and then Hanford, as the three secret cities or something. But the fact is the Met Lab at Chicago was enormously important. The Stagg Field reactor was historic in ’42, and its sort of dismissed.
All the chemistry on plutonium that went in to the major processing designs at Hanford was developed in the Met Lab at Chicago, transmitted to DuPont, and put into the design of Hanford. A lot of the reactor design—Eugene Wigner was working at Chicago and dealing with the DuPont people, and the DuPont people lived side by side with the people at Chicago, getting what they needed. So Chicago was the focus of a great deal, including the Oak Ridge pile design that started producing the first fissable amounts of plutonium at Oak Ridge and the techniques for analyzing it and separating it and bringing it back to Chicago. All that plutonium was brought back to Chicago. And the first visible amounts of plutonium then were—significantly visible amounts—were from the Oak Ridge operation.
So all of that preceded in effect the Los Alamos effort and I’ve always thought of Los Alamos of being a small part of the program and would have been obvious until they discovered spontaneous fission and plutonium-240, which meant they had to suddenly invent something. Up to then it was a gun assembly and there was just no great need for invention. It was a final test of whether there would be an explosion, and therefore the most spectacular, but probably the one with the most assured outcome.
So history is, to me, has been sort of lopsided because it fixes on the spectacular aspects. But the initial design by Fermi, the Fermi graphite lattice reactor—which seems obvious now—wasn’t obvious, because the Germans never attempted it. They thought in terms of heavy water reactor, which was much more ambitious, required a much bigger industrial effort, and was what’s achievable.
And I believe that counterintelligence, particularly on the part of the British, did everything they could to promote the notion in Germany that you couldn’t do it except with heavy water. And that’s what the Germans believed. So unless they could make large amounts of heavy water, the pile production of lots of plutonium didn’t seem achievable. And of course producing enriched U-235 was a massive industrial effort; it would have been bombed out of existence, unless it was all underground in Germany. So that shaped the history of the project in Germany in my mind, not the reluctance of Heisenberg or anybody to undertake it, it just looked impossible to them.
But the graphite lattice reactor was a brilliant invention that was carefully designed, to permit fast neutrons to get out of the fuel elements and slow down in graphite and diffuse back as thermal neutrons into the uranium. Why it didn’t occur to apparently to anybody but Fermi I don’t know, because like so many brilliant inventions it seems obvious after the fact. And Eugene Wigner, I guess at least mentioned in these—your outline—was really one of the brilliant contributors to making the Fermi reactor practical.
In fact, one of the famous stories is about the “Wigner disease” and how he designed against that. But when the Hanford reactor started up, they discovered also that xenon, one of the isotopes, was a tremendous poison and shut the reactor down again. But they’d overdesigned it—that was what DuPont had done. Without knowing what was going to go wrong, they produced a sufficient overdesign on the Hanford reactor to be able to put in extra fuel elements and compensate for the xenon poisoning, so that was extremely important aspect.
And also, a surprising fact that the neutron capture in uranium-238—which is a poison, fissile isotope as U-235—was anamously low. And if it had been as high as it is in most heavy elements, there wouldn’t have been any natural Fermi reactor. There wouldn’t have been any plutonium program, unless it had been based on enriching U-235 and uranium to what they presently do in pile reactors, up to three percent. Then they could have built a chain reacting pile and built plutonium, but that would have been a very unlikely thing.
So except for that unlikely event, that uranium-238 capture was slow, there would have been no Fat Boy—there would have been, what, Thin Man and the gun assembly of U-235. So it’s a remarkable thing this little matrix provided, the path—a smoother path to making bombs easier than they should have been. What do you want me to talk about?
Cynthia Kelly: Talk about your—how you got involved in the Manhattan Project.
Cowan: Well, I had remarkable good luck when I got my bachelor’s degree in 1941. My physics teacher—I’d majored in chemistry—my physics teacher thought I ought to be a physicist, and he was a good friend of Eugene Wigner’s. They both had emigrated from Europe, and he said that Wigner had been in touch with him. And they needed somebody who knew chemistry and could work with physicists and I should go down and talk with Wigner, and I did. And after he quizzed me for a while—I’d been off to the library looking up some stuff—he asked me to join his group, and it meant doing some graduate work at Princeton and working with his group on the cyclotron.
Based on his description of some of their problems and my early interest in the possibility of a chain reaction in uranium after the discovery of fission, I gathered that they were working on—what they were working on, and was very eager to join them and did. And I was the chemist, it turned out. I very soon went on three shifts, seven days a week. And I slept beside the cyclotron because I had to be available when these bombardments—and the job was to measure the neutron capture cross-section and above room temperature—the upper thermal capture cross section in uranium-238 of neutrons. Because if it was as predicted, it would have made the Fermi pile impossible. And it turned out the pile was possible and was successful.
We all went to Chicago in May of 1942 and I was assigned to Herb Anderson, Fermi’s group, and working with whatever Herb Anderson asked me to do, which was a number of things, including purifying uranium from fission products which I did at Princeton, which involved large amounts of ether which were both explosive if you handled it improperly and highly inflammable. Nobody had paid attention to these things in those days and so we worked in conditions that would be considered totally unacceptable now for that kind of thing. And machining beryllium, beryllium oxide—Herb Anderson got berylliosis doing that, fortunately I didn’t. Making radium, beryllium neutron sources—the beryllium was poisonous, the radium was enormously radioactive—we did that by hand essentially.
Eventually I would go to New York, the Uranium Corporation of America, which did the same thing in an office building in 6th Avenue—you couldn’t imagine doing that now. In fact that building was so radioactive—the roof was so radioactive where the radon came out—that it blasted my survey meter. I went back to work down there and never said anything about it. I don’t know how long it lasted in the middle of New York City on 6th Avenue but I’ve never heard any mention of it—Uranium Corporation of America just did what it chose, nobody worried about those things at that time.
And then of course there was Oak Ridge. I was sent down there when they started making plutonium because they couldn’t agree on how much plutonium they were making and I was a referee, I guess. I still don’t know whose methods they used, but I cast my vote and after a couple months I left and came back to Chicago.
And then the big problem was making sure that the plutonium that was delivered to Los Alamos was so pure that there was no neutron background in it from alpha particles of plutonium hitting light elements, which made neutrons. And that would have produced a pre-implosion in a gun assembly. And they discovered that the same thing happened in plutonium-240 from spontaneous fission, so they couldn’t do a gun assembly. So our job was essentially over-purifying plutonium.
And at that point some Colonel called me, or he came to Chicago actually from Los Alamos—and I don’t know who it was, I can’t think of his name—but I was on his list and he said, “You got to go to Los Alamos.” And at the same time I was talking to John Dunning who ran all the research on the gaseous diffusion at Oak Ridge—it was developed at Columbia. And there were major offices of Kellex and so forth running their program in downtown Manhattan. And John Dunning said, “Come work with me,” and I guess his name was sufficient to impress the Colonel or whoever and I went to New York instead of Los Alamos. I would have gone to Los Alamos if some friend had called me and said I had to come [chuckle] but I was still a civilian and not impressed by the Colonel’s authority.
And actually it was a wonderful stay at Columbia because I was working with Madame Wu [Chien-Shiung Wu] and Jim Rainwater and that group, they both won Nobel Prizes. I learned from Eugene Wigner at Princeton and from Bob Wilson when he was at Princeton, and from—I don’t know, there were seven or eight Nobel Laureates eventually—and the remarkable people I got to associate with, and I learned how real science is done. It affected my career and I feel that, again, I was extremely lucky to work with those people.
And also, I got the notion that scientists collaborated readily with one another, that there were never any proprietary arguments, that everybody was totally focused and everybody knew what the mission was. And at the end of the war I discovered that wasn’t so. It was the war and the threat that Hitler would achieve an atomic bomb, which everybody believed early on, that they were way ahead and should have been. But it turned out it wasn’t true.
But nevertheless the threat makes these remarkable people, who generally run their own show, work in an orchestrated pattern. And the moment that threat is gone they exploded all over the country, each to his own fiefdom and his own specialty, and keeping Los Alamos going turned out to be a major problem. They had to recruit fresh people. At that point I got an urgent phone call from my friends at Los Alamos to go there, so I left Columbia and I went there to see what was going on. There was a pretty chemist that I knew at the University of Chicago who had gone there, so I married her and took her back east with me as soon as I could.
Actually I first of all went overseas to Operation Crossroads, which was the first military test of the atomic bomb against navy ships. That gave birth to the famous picture, kind of a wedding cake coming out of the Bikini Lagoon with battleships placed on top it. That was the underground water explosion of the bomb, then there was an air burst. So there were two tests in Operation Crossroads and I participated in both of them.
When that famous wedding cake picture was taken I was on B-17 about three miles away with a photographer who took that picture. And when the shock wave hit us he fell out the door but he was strapped in, we pulled him back in, he and his equipment were strapped in so we had to rush over. I was the only one without an oxygen mask, we were at oxygen required, but I was a civilian and everybody else was Air Force—they’d forgotten to provide an oxygen mask for me, but that was okay. I didn’t fall very heavily on the photographer [chuckle], I was having a tough time breathing [cough]. But I do remember that we took many Gs—positive and negative shock—which would have torn the wings off most airplanes, but the B-17 was a remarkable aircraft and I can see why it survived so much anti-aircraft flak and stuff and bombing raids over Germany .
And then came back from Crossroads, I say I got married and finished my graduate work at Carnegie Mellon, which was then Carnegie Tech. And was asked to come back to Los Alamos when I got my degree, and I was interviewed by various people and did come back to the radiochemistry group. And three weeks after I came back, the Russians exploded their first atomic bomb, Joe-1, and some samples were collected with a highly secret operation going on in the Air Force. And the samples were—some samples were delivered to Los Alamos under such secrecy that the director, Norris Bradbury, didn’t know they were there. I remember the guy that showed up, wearing a trench coat just like in the movies.
And then after that, the job was to persuade the people in Washington that this was a bomb and not a reactor that had blown up. And that’s not an easy thing to do with people who don’t know what the physics and nuclear chemistry are.
As it turns out, it’s very easy to do enough fission products, since they have different half-lives and you know what they should have been at time zero to distinguish between a reactor, which generates its fission products over a long period of time, and one which generates its fission products all instantaneously. The profile of fission product distribution is entirely different, and in fact you can set the time that the thing, the explosion happened, almost precisely from just following the decay curves back to a common time of origin.
The argument then was finally accepted by Mr. Truman that it was a bomb. Edward Teller at that time argued very convincingly as I recall, that they probably did it with heavy water. He didn’t know they had simply gotten the design by espionage of a graphite lattice reactor—total design transmitted to them. So they didn’t do a heavy water reactor, they didn’t make that much heavy water. But he argued, since they had that much deuterium they could easily make an enriched thermonuclear device, so they could go quickly to a thermonuclear bomb once they had—because they had all that deuterium. Well, they didn’t have all that deuterium, they’d done it the same way we did.
Nevertheless, we suddenly went on a six-day week, forty-eight hours—actually it was seven days since we never stopped working—to design the first thermonuclear device. That was the big problem then and it really went on an accelerated basis—early 1950 and terminated in 1952—so it was less than two years of authorizing it to the first test of a major thermonuclear device.
And just a few months later the Russians did something called Joe-4, which was also thermonuclear. They did exactly what Teller had predicted, except they took all the deuterium they had essentially and put it into a device in which they were burning—I’m sorry, they took all the tritium they had—you make tritium with extra neutrons of lithium-6. And that was Teller’s argument, was that they would be making a lot of tritium, not deuterium. I misspoke. They took all the tritium they had and burned DT—DT reaction, deuterium plus tritium—which was much easier to do than what we call a real thermonuclear reaction, which is burning deuterium without the tritium. That was what Ivy Mike was, that was the November 1952 U.S. thermonuclear test.
Then it was all Cold War—the ‘50s were the Cold War race between Russia and the United States, which the most remarkable thing to my mind was the test of a sixty megaton device that the Russians did. And I never understood it. It had no military use at all. It was by far the biggest explosion that had ever been done, and they announced it in advance in effect to make sure that nobody missed it.
But not too many years later I got the Kremlin in Moscow and saw their big brass cannon—they were tremendous metallurgists in the early Middle Ages—and they made this huge brass cannon, which would have killed everybody around it if it had ever been fired. But instead they brought in all the members of the Russian power elite from the countryside and showed them this huge cannon, which made them tremble. So it was seeing that brass cannon that made me realize, that 60 megaton device was their modern equivalent of the brass cannon on the Kremlin. It’s the way they think—they think in terms of power and its symbols much more innovatively than people in Washington do. They think of military power, which is being demonstrated right now, and its overwhelming coercive nature, whereas the Russians thought in terms of symbols. We’re being criticized by using symbols badly, we always have.
After the, essentially the sensation of nuclear testing, Los Alamos went on to other things. But your history, I think, is one that stops with the development of military weapons, is that correct? I think so. I don’t know what else to reminisce about.
There are lots of interesting things that happened personally to me. I mean, meeting Edward Teller and Leo Szilard; the head of much of the French program, Le Halban, who was spirited out of France after the Germans conquered France. He was picked up by the British and somewhere on the Rivera and brought to England. And he was bringing with him all the heavy water that existed in France, put it in an open touring car, put a blanket over it, put his kids on top of it, went through a number of checkpoints [cough], and he described the experience to me.
And of course I met people at Princeton too. Dick Feynman, who was one of the first people I met. Everybody has a Dick Feynman story. He came into the office I’d just been assigned, he didn’t expect to find anybody there. He said, “Oh may I use your phone?” I said, “Sure,” and he whipped out a little screwdriver, took it apart, and left with a piece of the telephone. And I was looking at the pieces at the desk. And that night I met him at an eating club I was just told to join—that’s the way you ate dinner in Princeton. Dick was sitting opposite me and I said “Are you through with my phone?” And he said “Oh yes,” and he came in the next morning, put it back together, and left. But at the cyclotron there was a sign that said, “Don’t let Dick Feynman in, he steals tools,” so I was not the first person that he’d victimized, obviously. I learned later to listen carefully to everything he said. It’s all fascinating, again, learning how science is really done.
Cameraman: We need to change tape now.
Kelly: I thought that Arthur Holly Compton too, as somebody you may want to feature in this.
Cowan: Arthur Holly Compton, yeah I could tell you a story about Arthur Holly Compton.
Cameraman: Well, go right ahead because we—
Cowan: All right, well my story about Arthur Holly Compton is—number one, of course, he was Carl Compton’s brother, they were both highly distinguished—it was fun talking with them. When I was asked to go to Oak Ridge to help settle an argument about how much plutonium they were making, I was told to get down there as fast as possible. Right away I started getting phone calls from Oak Ridge from my friends saying, “Bring all the booze you can,” because it was a dry community and when you bought booze from bootleggers it cost two or three times more than buying it from a liquor store. So I packed a suitcase full of bottles of rye. They were hard to get, actually, because good whiskey wasn’t that available either, especially scotch, during the war. And then I packed my own suitcase, so I had two suitcases.
And I got on the train. I had a berth. And Arthur Holly Compton had suddenly gotten on it and was rushing down there, but nobody had been able to get him a berth. I offered him mine, but he slept that night in a chair seat, I think. Anyway, when we got to Oak Ridge—there’s a place you can stop which they don’t usually, the train goes to Knoxville but this was close to Oak Ridge—and he invited me to get off there and help me with my bags. He immediately picked up the thing full of booze, which tinkled back and forth. And he looked at it and said, “I’ll take care of this! [Chuckle]” So he handed it carefully to the chauffeur, who put it in the trunk. And the two of us rode into Oak Ridge, and he told the guy to be very careful [laughter] with the suitcase with the booze. And of course I was greeted by all my friends waiting to divvy it up. So that was my closet collaboration with [chuckle] Arthur Holly Compton. He was a very kind, human, thoughtful person.
Kelly: You said you knew Szilard. Leo Szilard.
Cowan: Yes. Leo Szilard was somebody I really got to know when he presided over things at the Dupont Plaza, which is on Dupont Circle. When we started going to Washington, trying to persuade the Truman people that—well, there was immediately something called a Bethe Panel, which Hans Bethe presided over, which has still never been widely publicized. It was highly secret, but the euphemism was—it was—it followed foreign technology. Actually, it was designed to look at all the possible intelligence aspects concerning Russian nuclear weapons activities.
So we went to Washington regularly and stayed at the Dupont Plaza, which was where Leo Szilard stayed. Joined him for breakfast in the morning, that kind of thing. So that’s the way I got to know Leo Szilard. I met him initially at Princeton in 1951, or ‘41 or ’42. And that was when Edward Teller would show up and they would start talking Hungarian and I thought I’d have to learn Hungarian—Wigner, Teller, Szilard—but I never did learn much Hungarian.
The von Halban story was to me a great story.
And there was also more than one fire. The Princeton group decided it needed as much metallic uranium as it could get to do some neutron absorption on metallic uranium. It turned out the only place that made it was a place called Metal Hydrides, I believe—it was in Beverly, Massachusetts. And I think it was Thoma Snyder, a very eventually famous physicist, and I were delegated to go up there and get some uranium metal. And it turned out it was finely divided, and when exposed to air spontaneously caught fire. It was under a blanket of CO2, and we were given our metal in a container and in a big bucket, wash bucket loaded with slabs of dry ice. And I was in the passenger seat with this thing between my legs, and my instructions were that if anything caught fire to open the door and kick it out. And nothing caught fire. We got to Princeton and took it into my lab. It was on the ground floor with a door out onto the lawn. And we opened that door and then opened the can of uranium, and it immediately caught fire and we tossed the whole thing out onto the lawn and it burned down into the lawn about a foot. And so far as I know it’s still there, we covered it over.
And we needed another source of metal—we couldn’t use that, obviously—and I was assigned the job of finding out where we could get it. And I did some research and discovered they had made uranium metal for lamp filaments not very far away at Bloomfield, NJ. Westinghouse was trying out every kind of element you could possibly make a lamp filament out of and uranium was one of them and the people that made it were still there. They had a patent on it. And we went up and told them we needed a kilogram.
“My god, that’s a lot more than a lamp filament. Well yeah, maybe we could do that, when do you need it?”
“Oh no, that’s impossible.”
So they had to explain to the White House, it turned out, why that was impossible, so they decided it was possible.
And sure enough, they put everybody to work on it, they delivered right above pure metallic uranium, cast the way we wanted it. It was the beginning of a major industry for them because they then became major suppliers. They were the people that understood how to make pure uranium metal and they suddenly discovered that it was one of their major wartime activities. And that was the beginning of a source of supply that never stopped, it was critical to the war effort. There were lots of things like that. Everything that we did was being done for the first time [chuckle], so it’s all a start.
Kelly: You mentioned Kellex?
Cowan: Hmm? Kellex.
Kelly: Did you ever know or know of Dobie Percival?
Kelly: The man who headed the Kellex project?
Cowan: No, I dealt with Dunning. Dunning was their principal scientific advisor and the guy who suggested that gaseous diffusion was the way to go. Of course, they then had to invent the barriers and all the plumbing and so forth, because UF-6 isn’t that nice to work with. But I worked with Dunning and he thought originally I might work with Kellex, but then he decided I would fit into his group, which as I say was full of really great people. And so that was much to me—working at Columbia was much better.
And I learned there about neutron time of flight, which means if you have neutrons of various energies meet in a pulse at a cyclotron you can sort out their energies by letting them fly down a vacuum tube. The fastest, the most energetic ones arrive first, the slowest ones arrive last, so you sort them out by time. And you can find out what the properties are of neutrons at given energies by keeping track of when they arrive. I used that later with bombs. We let the neutrons from the bomb come down the tube just the same way, except now, instead of arriving one neutron at a time, they arrived many millions of neutrons at a time and you could do things with them that you couldn’t possibly do with a cyclotron.
And so I became famous for inventing the so-called wheel in which we’d capture the neutrons, in a metal wheel which revolved in front of a slit. As the neutrons arrived, they would be captured in this metal, each in its energy range, so that they were separated on the metal by neutron energy. And we were able to measure the fission properties of individual resonances in uranium-235, which never had been done before except by instrumentation. And we did it in ways that produced new information. That stuff is written up in the literature and it’s something brand new.
My colleague at that time was Tony Turkevich, who died last year. He was my constant colleague and friend, professor at the University of Chicago. Tony was one of the original big contributors to the Dunning program, the gaseous diffusion. He worked for Kellex eventually, came to Chicago, and then went to Los Alamos and was present at the original test. He was also a good friend, as was a good friend of mine, Nick Metropolis, who is one of the inventors of the Monte Carlo method and is frequently mentioned as the most cited author in the scientific literature because everybody used the Monte Carlo method—they always refer to it as Metropolis L.
I should mention maybe that one of the great things in the postwar era was the Theoretical Division poker club. I was not a member of Theoretical Division, but I was a member of the weekly poker group. And it had traveling guests: Edward Teller played, Johnny von Neumann played, just about everybody that came by that was willing to play poker would be invited to play in that poker game. So it was more of a social occasion. [Inaudible] was one of the players, Nick Metropolis, Jim Tuck, and Carson Mark was the captain and leader of the thing. So many of my memories of that time were associated with the great nights we spent playing poker.
The wartime—the attitude toward the test, the atomic bomb test: all the scientists that I knew of were for a demonstration. The fact that they were for a demonstration was not transmitted to Truman. He was working as the brand-new President at the time; didn’t know beans, I think, about the bomb project. He turned it all over to the Secretary of War, Stimson, and it was run from the War Department. And they weren’t listening—taking advice about demonstrations—they were going to demonstrate that thing over a Japanese city and that’s the way it went. So I don’t think the opinions of the scientists mattered one way or the other. They just never were transmitted; they never were taken seriously.
And looking back at it, the scientists aren’t qualified politicians. And in the ‘80s when I started the Santa Fe Institute—it was because I was supposedly on the White House Science Council giving advice to Mr. Reagan—I realized that scientists don’t give advice to politicians. They help support their policies and if they don’t support their policies it doesn’t matter. At that time, one of the big issues was whether or not space platforms should be manned or robotic, and White House Science Council voted unanimously for robots. Mr. Reagan said, in effect, Congress would never pass that program unless there were people on it, so the policy was political and that’s what determined the fact that we had manned space missions. I think I’m through telling war stories.
Kelly: Well, you’ve been great. This has been fabulous. You’ve done a great job and a lot of this is going to be very useful. And I think your point is very well taken that we have not—the draft does not speak to the work that was done in Chicago—
Cowan: Well, you know Glenn Seaborg, after all, went on to become first Chairman of the Atomic Energy Commission; Nobel Prize Winner; he and Art Wahl invented plutonium—and I don’t think you mentioned his name. He was unpopular and was persona non grata at Los Alamos. Art Wahl was here, he was Glenn Seaborg’s collaborator as a graduate student.
By the way, Art Wahl is still here. He came back from University of Washington—no, Washington University, St. Louis. And he’s an old man now; I don’t know whether you want to talk to him. He’s bent over and more or less crippled, but he’s one of the co-discovers of plutonium, he and Glenn Seaborg are the co-discovers of plutonium. And so they, in a sense, were the beginning of the whole plutonium program.
Kelly: It’s really, I think, going to be fascinating for most people to realize that so much of these seminal events—the discovery of plutonium, the discovery of fission—all happened within just a couple years or even months, before this whole project.
Cowan: Yeah, the discovery of fission was in ’38, the discovery of plutonium was in ’39 or ’40. The first successful bomb was in ’45. The whole thing was telescoped into a period of time, which if you tried to do it now you’d have to invent a war or some overwhelming threat which would drive those people together—I mean, similarly competent people together. Usually every one of them will be running their own show—have his own corporate activity in effect, his own funding, his own ability to do anything and go anywhere. Putting them together in an enterprise like was represented at Los Alamos or another star group at the Met Lab at the University of Chicago—it takes an external pressure. And the moment that pressure is relieved, things go back to a different style. And what we did those few years—if you were to do it in the other style—would probably take two decades, anyway.
Of course, the fact we had an overwhelming priority on everything; you could get whatever you needed, whatever resources you needed, including people by name. And that makes a difference: if you can name a hundred people by name, and get them involved, and it’s the right list of hundred people, you don’t need a large enterprise. You can get all the support from that center that’s needed by picking up a phone. But putting the right people together makes impossible things happen.
Kelly: Well that was—
Cameraman: Is that what you tried to do with the Santa Fe Institute, was to—?
Cowan: My mission with the Santa Fe Institute was to get the kinds of people I knew, who knew how to get things done, involved in social and political science, where people gesture and shout at each other and march around in circles, at least that was my impression. And there are still people gesturing and shouting at each other and marching around in circles, so I guess we didn’t change the world, but that was the general notion.