Theoretical Analysis of the Observed Asymmetry in the Fission of Actinides.

[NNadir]

6. Thank you for your comment. I never heard that story about Bohr and Teller.

You do have a good sense of the details of this history, which is very nice to see.

I will confess though that I see them in a different light.

The Heisenberg/Bohr meeting has received a great deal of attention because of Michael Frayn's wonderful play; I saw the film version of it. By the time of that meeting however, neither man had any power whatsoever to do anything about the potential for nuclear war. One man, Bohr, was half-Jewish in a Nazi occupied country; the Nazis being in the awful position of rejecting "Jewish Physics," of which Bohr and his only peer, Einstein, were the ultimate representatives. Even Heisenberg had been criticized in the Nazi press as a "White Jew."

There is no way in hell, in any case, that any scientist who had escaped Nazi Germany, Szilard, who you mention, and more notably men like Bethe, Fermi (who escaped from Italy with his Jewish wife), Szilard, Teller, etc...would have given any credibility to any "promise" made by Heisenberg. Heisenberg - and to a far lesser extent - Hahn was the reason that these scientists were terrified by German science. Heisenberg was widely known as a German nationalist; not a Nazi necessarily but very much a German nationalist. They would have simply attributed anything he said to disinformation.

As late as 1944, at the famous meeting at the Paul Scherrer Institute - where the American agent and former major league catcher Moe Berg had been sent to decide on whether or not to assassinate Heisenberg - Heisenberg, agreeing with remarks that Germany appeared to have lost the war remarked that it would have been wonderful if they had won!

Frayn's play, and I've seen him so confess, puts a highly inaccurate spin on that meeting, which is way too sympathetic to Heisenberg. We know this because of Neils Bohr's habit of writing letters to clarify his thoughts on a subject, without actually sending them. Such a letter apparently exists that he'd composed to Heisenberg in the late 1950's if I recall correctly, and after Frayn's play was written and produced, was then released by Aage Bohr. It puts to rest any notion that Heisenberg was there on a mission of peace to prevent the development of nuclear weapons. He was there as a representative of a conquering power, there to perhaps try to justify himself to his mentor, but it appears that Bohr would have none of it. (I have also read that Margrethe Bohr never liked Heisenberg, even when if he did world shattering physics with her husband.)

I mentioned in this space recently that I had obtained the Farm Hall transcripts: Wow. I just got my hands on the Farm Hall Transcripts, annotated by Jeremy Bernstein. I certainly haven't found the time to read all of them, but what I have read convinces me of my growing opinion that the main reason that the Germans never came close to building a nuclear weapon was that they couldn't get the necessary funding for it, and even funding for a reactor was increasingly difficult to obtain.

When Bohr arrived in the United States, the technological advances in nuclear energy had already passed him by. Groves viewed him as nothing more than an annoyance - a distraction to "his" scientists - who needed to be tolerated because of his enormous and well deserved prestige among them. His main use was an ineffective attempt to inject some morality into the project, but he was more scientist than diplomat. He had essentially no power to stop anything or even to change its direction.

I never actually looked at Szilard's patent until you generously excerpted it here. The patent was filed before the discovery of nuclear fission and before the eta value - the neutron multiplicity - of fission was known, but it did certainly offer in general terms something of the idea of a chain reaction. From what I read briefly, however, it would not have worked to do very much at all. From what I recall - and I could be wrong about this - a similar approach may have been tried to generate technetium for medical testing around the time that the Petten reactor went down for repairs.

Irrespective of its merits, the idea, once fission was discovered, certainly motivated Szilard and his famous drive to get Einstein to write the letter to Roosevelt by which the Manhattan Project was brought into being.

Glenn Seaborg, along with Oppenheimer's scientific administration, and most importantly, Fermi's ability to bridge theory and practical experiments along with practical engineering, and perhaps along with Bethe, were the critical people in the Manhattan project. It seems to me that if any one of these men, most importantly Fermi - particularly when it came to understanding xenon poisoning - had been missing from the project, it would not have succeeded in producing a nuclear weapon before the end of World War II. In counterfactual history, perhaps in order to justify the expense, a failure to produce a weapon in time for use might have lead to the development of nuclear power without the element of fear which dogs the vastly superior energy technology that is humanity's last best hope.

I can't say, and as you say, we live in the world that is, not the one that might have been.

It is not the case, however, that anything learned by the use of academic cyclotrons from which Seaborg and MacMillan's early work depended could have lead to the development of nuclear power without the massive investment the Manhattan project represented. Seaborg spent much of his career producing invisible quantities of elements that were only detectable because of their extremely energetic decay. I've seen at least one portrayal of the events describing the arrival of Groves to the project in which he is shocked to learn that the whole project depended on the properties of materials available in quantities to small to be seen.

It is a credit to Groves that he logistically administered the scale up from atoms to kilograms, which Seaborg considered to be one of the greatest scale ups in history; and it was very much so.

Thank you for your interesting and well informed post.