Allison, Samuel

Shortly after Japan s December 7,1941 attack on Pearl Harbor, the U.S. became more driven to expedite its timetable for developing the first fission weapon because of fear that the U.S. lagged behind Nazi Germany in efforts to create the first atomic bomb. On December 2, 1942 at 3 49 p.m., Enrico Fermi and Samuel K. Allison achieved the world s first controlled, self-sustained nuclear chain reaction in an experimental reactor using natural uranium and graphite. 

G.4 Arthur H. Compton and Samuel K. Allison. X-Rays in Theory and Experiment (New York D. Van Nostrand, 1935). A standard treatise on the physics of x-rays and x-ray diffraction, with emphasis on the former. 

Bush and Conant proceeded to order up from Arthur Compton a third NAS review. Compton asked Samuel Allison for the name of someone who could help him calculate the critical mass of U235. Allison had been corresponding with Enrico Fermi on the subject of carbon absorption cross sections and recommended him highly. Compton called on Fermi in his... 

Greenewalt called Samuel Allison in Chicago on Friday afternoon. Allison passed the bad news to Walter Zitm at Argonne, the laboratory in the forest south of Chicago where CP-1 was meant to be housed and where several piles now operated. Zinn had just shut down CP-3, a shielded six-foot tank filled with 6.5 tons of heavy water in which 121 aluminum-clad uranium rods were suspended. Disbelieving, Zitm started the 300-kilowatt reactor up again and ran it at full power for twelve hours. It was primarily a research instrument and it had never been run so long at full power before. He found the xenon efiect. Laborious calculations at Hanford over the next three days confirmed it. 

Hornig and Samuel Allison. With the beginning of the final countdown Groves left by jeep for Base Camp. For protection against common disaster he wanted to be physically separated from Farrell and Oppenheimer. 

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