Scientific Work in Los Alamos Program

What are the main problems of assembling a plutonium bomb? Who was assigned to express scientists’ opinion during the Los Alamos Project? Mallinckrodt Professor of Physics at Harvard University and Nobel Prize winner in Physics, Roy Glauber, speaks on the history of nuclear weapon invention during World War II.

Half of reactive mass, more than a certain critical size – it means that the neutrons are most likely to start chain reactions before sufficient escape has taken place of the neutrons. In a situation like that with no moderation, no slowing down of the neutrons, it all develops very quickly. Well, now you have the question how do you ever get to one of these situations, in which the mass is above the critical mass and in which there is a loan of probability that the neutrons escape without inducing fission, so that a great deal of fission takes place. Well, you see there’s a kind of contradiction in that. What you would have to do is put the masses of a fissionable material together into a supercritical configuration so quickly that it would happen before any explosion could take place. Otherwise, if you do it all slowly you get a condition called ‘predetonation’, in which the explosion begins before any serious explosion can take place, just because of the configuration of the matter

Many of the scientists threatened to leave in 1943 until the general, who was directing the project, realized that the only way of doing this was to keep civilian control, and the man he had chosen for this was a remarkable choice, Robert Oppenheimer. It was Oppenheimer who expressed the opinion of the scientists, and General Groves had only to agree with that. That held the project together.

Once the explosion had taken place, once the secret was out, which happened very quickly, there was still a number of secrets retained, various surprises that we had had along the way, which were left as possible surprises to any other country that wanted to undertake this. There were questions raised, we were all asked for suggestions on what might be the peaceful uses of nuclear weapons. Very few suggestions emerged and none was ever acted upon. To my knowledge, there has been no practical application of nuclear explosions other than as a weapon. I’m sure there’ve been developed many different weapon-like applications as artillery or what have you, but none of the suggestions that anybody made had any value at all for peacetime purposes.