Francis (Franz) Simon was a German-born chemist and physicist who emigrated to England. He invented the crucial gaseous diffusion method of uranium enrichment. He doesn’t figure much in my story of power reactors but, to be on the safe side, I dutifully read a fairly recent biography by a Canadian academic. Here’s a fascinating cameo scene in Oxford towards the tail end of 1954. What you need to know is that Klaus Fuchs, the most famous atomic spy, is about to be arrested:
On Sunday 20 November, Niels Bohr was scheduled to visit Harwell and give a lecture. Franz, by arrangement with Cockcroft, spent part of the previous evening arranging for the Bohrs to come to Sunday tea afterwards at Belbroughton Road. The diary for Sunday charts the day hour by hour. At 11, Franz left for Harwell with Maurice Pryce, Born’s son-in-law and a theoretical physicist. There they met Bohr, Fuchs in his usual role as guide, and Cherwell. Bohr delivered his lecture, and Pryce and Simon were home in Oxford by 1.20 p.m. Franz had dinner and a short rest before the first guests arrived. Before they did, he drew Dor aside with an odd request: “When they arrive, I want you to show Fuchs around the garden.” She had met Fuchs previously when she stayed briefly with the Peierls family in Birmingham while taking a training course with ICI. At first reluctant, the firmness of the request left her no option but to agree. At 3.00 p.m., the Halbans arrived, at 3.20 the Pryces, and then at 3.30 Professor and Mrs Bohr, the Indian physicist Homi Bhabha, and Fuchs. While Fuchs was being shown the garden, the topic of conversation indoors is noted in the diary as “Russian bomb and consequ[ences].” At 4.15, more guests arrived, and the “Tea Party” proceeded more conventionally until 6.30.McRae, Kenneth D. 2014. Nuclear Dawn: F. E. Simon and the Race for Atomic Weapons in World War II. Oxford University Press, United Kingdom, loc. 5,547-5,562.
I noticed this paragraph because I was keeping close track of Indian physicist Homi Bhabha, then briefly visiting Cockcroft. We see Bhabha admitted into private high-level physicists’ gossip whilst Fuchs gets diverted just prior to being detained. This is the only mention of Bhabha in the bio.