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Marshall Rosenbluth on: The George Test
Q: You started to work on the George, in preparation of the George shot? Was that in the summer of 1950?

MR: Yes, that probably was. There was the booster and there was also George which were tested, I guess, in '51. I was certainly heavily working on the booster and some work on George.

Q: When you say heavily working on the booster and some work on George, you were doing what exactly?

MR: Well, trying to calculate the physics of what would happen and what dimensions things should have and so on and so forth.

Q: What was interesting about George? What was special about that experiment?

MR: Well, by putting the DT outside the bomb, you were able to get very good diagnostics of temperature, say, versus time, and to see if all the calculations you were doing were right or wrong. So, it was the first clean demonstration of thermonuclear burn. Not that anybody had grave doubts or particular doubts about it, but the details of how the burning material interacted with the outside world and so on were complicated, and there were uncertainties in the calculations. And then, of course, the idea of pumping the radiation out to the capsule later proved to be sort of the chief idea in the design of the bomb. So, I think, at least my own view, has always been that by committing to George - which didn't really have a terribly clear-cut objective at the time it was proposed -- that started us thinking in detail about all the physics and a lot of the pieces fell into place as to which someone like Teller could then much more easily put together. I mean, if you have some idea like using one bomb to set off another bomb, unless you really sort of calculated the detailed phenomena, you don't know whether it makes any sense. And if it is totally abstract, you may not really bother to calculate all the phenomena, but with something like the George shot, where here was an experiment you were going to do and it would tell you something about thermonuclear burning, you weren't quite sure what it would do, but you had to go through the whole business of the interaction of radiation with matter and hydrodynamics and so on and so forth in order to understand its behavior. That kind of familiarized people, I think, with the essential physics.

Q: What was the idea behind putting the DT outside?

MR: I think the main idea was just to make the diagnostics much better. You can look at what was going on without looking through all this layer of metal and outside all the HE (high explosives) and stuff like that. So, it was just a cleaner experiment, I think was the basic motivation.

Q: Where did the idea come from with pumping the energy, the radiation to that capsule?

MR: I don't know. I think, once you are going to decide you wanted to burn the DT outside the bomb then it was a fairly obvious idea, I mean the radiation is what is first emitted. For example, if you waited for the shock wave, the radiation would already have blown everything up. So, it was the first thing that would get out before any channels and such would have time to close off. So, once you decided you wanted this external burning, it was a fairly obvious idea. I don't know whose it was.

Q: And that realization really came with the exact calculations.

MR: Yes, I think it did. Some of the phenomena, I am not really sure whether some of them are classified still or not, some of them had not been thought of until one tried to do careful calculations.

Q: Where you involved in that work yourself?

MR: Yes, that is what I was doing?

Q: So, where there moments when you were doing these calculations where you realized that there was something new in that?

MR: Yes, several such.

Q: Can you elaborate?

MR: Well, as I say, I really don't know whether some of those things are still classified. I didn't have any of the big ideas, but I think a lot of details of how things would work and what dimensions and things like that one should use, I worked out.

Q: What was Teller's reaction when you came with these results?

MR: Well, he was very interested. He followed it closely.

Q: And it was news to him, too, at that point?

MR: Yes, I think so.

Q: So, we were talking about the Teller-Ulam breakthrough, and Teller first telling you about this. When he presented this new idea to you how did you respond to that?

MR: Well, I guess, I really don't remember exactly how I felt, but it certainly had a very plausible ring to it. I said well, I want to calculate this and look at it and so on and so forth, but it certainly sounded a lot more promising than what I had heard before. Again, from having worked on these other things, I had some feeling for the physics involved in this new idea. It was complicated enough, I certainly couldn't give a off-hand opinion, but it sounded very plausible and credible.

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