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"Using mostly X-ray and microwave equipment from the physics labs, he and Norris Bradbury ... built [a neutron] source ... . (Bloch later pointed out that this equipment was more important as a source of inspiration than of neutrons.) Eventually, he extended his use of neutron sources to studies of neutron polarisation, a link to his earlier research in ferromagnetism. [Felix Bloch] Courtesy Stanford University Archives These studies served as a basis for a collaborative effort with Luis Alvarez ... . In the fall of 1938, Alvarez and Bloch began working with Berkeley's 37" cyclotron to determine the magnetic moment of the neutron. ... By the summer of 1939 ... they were able to publish very precise results. This experiment was, in fact, one of the first important uses of Ernest Lawrence's cyclotron. .. In 1942, [J. Robert] Oppenheimer asked Bloch to work on the Manhattan Project. Bloch, collaborating with [Hans] Bethe, [Edward]_Teller, and [Hans] Staub, used the homemade Stanford cyclotron for the first experimental determination of the energy distribution of neutrons from fission. After this was completed, Bloch left for Los Alamos, New Mexico where he worked on special theoretical problems under Bethe's supervision. At a meeting of the American Physical Society in December [1945]. Bloch met... [Edward]_Purcell of Harvard University and the two discussed their recent research. Both recognized that the theoretical basis of their respective projects was the same, although they had been using slightly different techniques to achieve experimental results. So they decided to split up the field: Bloch would use the effect in the study of liquids; Purcell would examine crystals. The Stanford group gathered its first positive results in January 1946 (see Physical_Review_69,_127(L)_(1946)). " Bloch was recognized for his achievements when he was awarded the 1952_Nobel Prize_for_Physics for the ‘development of new methods for nuclear magnetic precision measurements and discoveries in connection therewith'. Further recognition for Bloch came in 1954 when he was asked to serve as the first Director-General of the European Center for Nuclear Research (CERN). After a year in this position, he returned to Stanford where, "[d]uring the next few years, he and Leonard Schiff, department chairman from 1954 through 1966, built one of the leading physics teaching and research facilities in the world. They and the other senior members of the department persuaded the Atomic Energy Commission to construct the huge linear accelerator" (SLAC). "As such a well-known scientist, Bloch was involved with many professional organizations... includ[ing] the American Academy of Arts and Sciences, the American Philosophical Society, the National Academy of Sciences, the Weizmann Institute of Science, and the American Physical Society. He was appointed an honorary member of the Swiss Physical Society and received honorary degrees from Grenoble University, Oxford University, the University of Jerusalem, and the University of Zurich. In 1965, he served as president of the American Physical_Society, one of the largest scientific organizations in the country." - Edited excerpts from Biographical_Note:_The_Life_and_Work_of_Felix_Bloch Top ***** Resources with Additional Information ***** Additional information about Felix Block and his work is available in full text and on the Web. *** Documents: *** A_Quantitative_Determination_of_the_Neutron_Moment_in_Absolute_Nuclear Magnetons; Physical Review, Vol. 57, Issue 2: 111-122, January 15, 1940 Fission_Spectrum, August 18, 1943 A_Quantitative_Determination_of_the_Magnetic_Moment_of_the_Neutron_in_Units_of the_Proton_Moment; Physical Review, Vol. 74, Issue 9: 1025-1045, November 1, 1948 A_Direct_Determination_of_the_Magnetic_Moment_of_the_Proton_in_Nuclear Magnetons; Physical Review, Vol. 80, Issue 2: 305-306, October 15, 1950 Theory_of_Line_Narrowing_by_Double-Frequency_Irradiation; Physical Review, Vol. 111, Issue 3: 841-853, August 1, 1958 Energetic_Stability_of_Persistent_Currents_in_a_Long_Hollow_Cylinder; Physical Review, Vol. 128, Issue 4: 1697-1714, November 15, 1962 *** Additional Web Pages: *** Chronology – Bloch (Felix) Papers; Online Archive of California, Stanford University Archives Bloch_Equations The_Bloch_Theorem Bloch_States:_Not_for_Electrons_Only A_Life-Saving_Window_on_the_Mind_and_Body:_The_Development_of_Magnetic Resonance_Imaging Biographical_Memoirs_V.64_(1994); National Academy of Sciences; Felix Bloch – pages 34 - 71 Top [U.S._Department_of_Energy] [Office_of_Science] [Office_of_Scientific_and Technical_Information] Website_Policies/Important_Links [Science_Accelerator] [science.gov] [WorldWideScience.org]