|GOFMAN:||We proved we had four-millionths of a gram, and by then things had moved along. The Manhattan Project had gotten started. Things even became easier at Berkeley, [with] the Manhattan Project backing and the Army. If you needed something, they could even put a triple-A priority on it and get it off the train going somewhere else. So, the work was enormously facilitated when the Manhattan Project people came [to Berkeley].|
|GOURLEY:||Who came in from the Manhattan Project?|
|GOFMAN:||Harold Fidler, who was later with the Berkeley Rad [(Radiation)] Lab. He
was, I think, a Major or Colonel and he was assigned to the Berkeley Project. I
got to know Harold, then. I got a lot of help from them in a variety of ways.
One thing, for example: We wanted to know whether uranium-233, which we'd just discovered, would be fissionable. Would it or would it not be like plutonium or like 235U? We had a small neutron source made with a mixture of polonium and beryllium. It was weak, it was just not enough so we decided we had to have about a gram of radium. That's a curie. (That's dangerous to handle, by the way.) We bought the gram of radium for $10,000 and mixed [it] with the beryllium that came in a lead block to Berkeley.
By then, Seaborg had gone off to Chicago. Because the vision of the effort under the Manhattan Project was Harold Urey at Columbia. [Urey] was going to try to work out the gaseous diffusion method of separating 235U. Arthur Compton of Chicago [was trying] to figure out whether a reactor would run; that was the Fermi Project. Also, if a reactor did run, could you make enough plutonium? The third thing was Ernest Lawrence's electromagnetic separation at Berkeley. Although I got to know Ernest Lawrence very well later, I did not participate in the Ernest Lawrence Project. I was working with Seaborg.
When I finished the work on 233U, I became the fourth chemist in the world to work with plutonium. Really, they say Seaborg and McMillan were the first two. The guy who really did the only chemistry that was worth talking about before I got in was Arthur Wahl. He was a graduate student one year ahead of me. He knew everything in the world there was to be known about plutonium, and he taught me. And I got started at the same time.
At the same time, I was getting ready to measure whether uranium-233 was fissionable. The radium and beryllium source, which is a strong neutron source, arrived. I had to be able to move that radium source up to a fission chamber and also test it with paraffin surrounding the fission chamber [and] without the paraffin slowing neutrons down, versus the high-speed neutrons being made in the reaction between the radium alpha particles and beryllium.
I was having the shop make me a lead train to move my source up to the fission chamber because it was too dangerous to handle by hand. The shop had a lot of priority jobs and they couldn't do it all at once.
Seaborg came back from Chicago, having gone there to head the plutonium section [of the Metallurgical Laboratory, Manhattan Project] in Chicago. I stayed behind in Berkeley. And he said, "How are the fission measurements going?" I said, "I haven't done them yet." And he said, "You haven't done them yet, with a war going on, you haven't done the fission measurements!" I said, "Glenn, I haven't done them for a very distinct reason: The lead [train] isn't finished." He said, "Don't worry about that, let me show you how to handle it."
He went over to the Old Chemistry Building, that was torn [down] later. We went over [to] where I had the lead block with my gram of radium. He got a stick and tied a string to it: "Just hold it out there and put it in front of the fission chamber and then put it back."
He was there for 5 minutes, but I was going to do that every day to take measurements. That's probably where I got a major share of what dose of radiation [I received] from that operation. A gram of radium is a roentgen per hour at one meter; when you handle things at a small fraction of the meter, dose goes up as [the inverse] square [of the distance]. So, I got a good [(appreciable)] dose.
But we succeeded, and we proved that uranium-233 was fissionable [with slow and] fast neutrons. Therefore, it was one of three [materials] in the world that you think of making bombs out of, although you can only get it by having thorium, or a mixture of thorium and uranium, irradiated in a reactor. A lot of it has been made since, and bombs have made out of it, too.
Since I was all set up for the fission measurements, I [measured] uranium-235 and plutonium, too. An interesting thing happened when I made those measurements. Professor Oppenheimer wanted to see the measurements.
|GOURLEY:||Now, where was Professor Oppenheimer?|
|GOURLEY:||He was also there?|
|GOFMAN:||Yes, before Los Alamos. Professor Oppenheimer was looking at the
measurements for calculations. [I looked at Oppenheimer's equation, and] I said,
"Isn't there a factor of ten to the sixth that is wrong here?" He looked at it,
and said, "Yeah, it doesn't matter." He was a remarkable guy.
So, what happened was that Seaborg had gone off to Chicago and I completed the uranium-233 work. There was one episode before Seaborg left that was very interesting.
Graduate students were rather playful. Seaborg's lab, where I worked, was on the third floor of Gilman Hall on the Berkeley Campus. As I told you, Dean Lewis had been the Father of Thermodynamics. Thermodynamics always use big water baths to control temperature of their vessels and operated at a certain fixed temperature. But that era was all over in Berkeley. There [were] big bathtubs out in the halls. In fact, one on top of the other, on the third floor of Gilman Hall.
I don't know what got into us, but Wahl, Spofford English, Bob Duffield, and I were working one Friday night before Seaborg had left for Chicago. We decided we'd stack those bathtubs in Seaborg's office, Which is where we [were] working on our counters and things. I don't know [why], it never occurred to us.
We were there the next morning, Saturday morning, working: Art Wahl, Spofford English, and I. The door opened and there is Seaborg with a visitor. And who was the visitor? It was Harold Urey, who headed the New York operation of gaseous diffusion [research].
Seaborg, without cracking a smile or anything, stepped into the bathtubs because he couldn't do anything other than that; there was no room left. Urey stood in another one. Now, these are some famous people, and there was a famous mental exchange.
Urey said, "Glenn, I think we ought to give up this plutonium project." And Seaborg said, "Why do you say that?" Here we are just completely crushed. What a mess we made, and Seaborg, and Harold Urey standing in bathtub[s] in room 203 [of] Gilman Hall. Urey said, "Look, I don't know how long the war will last, but I don't see any possibility that you can learn how to isolate plutonium from that mess we have of fission products and uranium in time for the war effort." So he said, "I think we ought to give it up and just focus on uranium-235," [for] which Ernest Lawrence had one project and he had the other. Fermi's reactor had already run, so it was assured you could make the plutonium.
Seaborg was uncanny in one feature. He had an uncanny knack for being able to see ahead, what would be important and what might not be important. He said to Urey, "Oh that's no problem, Professor Urey, we worked all the techniques out for separating plutonium once it's made."
There we were sitting-remember, Wahl was the only guy in the world who'd worked with plutonium and I was the second one, besides Seaborg and McMillan. We knew damn well what we didn't know. Here he's telling Urey, we have all the techniques worked out! It's the furthest thing from the truth, but I guess he figured we'll work it out.
Then they left. We cleared the room up, and he never said a word about those bathtubs being put in his room. One of the most famous conversations in the whole war in that room with Harold Urey suggesting we stop the plutonium project. Well, we didn't stop the plutonium project, as you know.