|
The Frisch–Peierls memorandum was the first technical exposition of a practical atomic weapon. Written by Otto Frisch and Rudolf Peierls in March 1940 while they were both working at the University of Birmingham in England, the memorandum contained new calculations about the size of the critical mass needed for an atomic bomb, and helped accelerate British and U.S. efforts towards bomb development during World War II. ==Background and influence== Given to Marcus Oliphant, Oliphant passed the document on to Henry Tizard, chairman of the Committee on the Scientific Survey of Air Defence who consequently requested the setting-up of what was to become the secret MAUD Committee. The memorandum (a copy of which is held in the Public Record Office at Kew) is dated March 1940. The two men were the first to calculate that an atomic bomb would require about of the isotope uranium-235.〔 "The energy liberated by a 5 kg bomb would be equivalent to that of several thousand tons of dynamite, while that of a 1 kg bomb, though about 500 times less, would still be formidable." 〕 (The estimate of 1 kg turned out to be too low; see Critical mass.) Before it had been assumed that the bomb itself would require many tons of uranium, implying that it was theoretically possible, but not a practical military device. An earlier letter to President Franklin D. Roosevelt, signed by Albert Einstein (but written by Leó Szilárd), had suggested it may need to be delivered by ship but "might very well" not be small enough to drop from the air. The memorandum helped galvanize both Britain and America down a path which led to a report by the British MAUD Committee, the Tube Alloys project, the Manhattan Project, and ultimately the atomic bombings of Hiroshima and Nagasaki. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Frisch–Peierls memorandum」の詳細全文を読む スポンサード リンク
|