جون ر. دننگ

John R. Dunning
John Dunning grave North Cemetery Sherman, Fairfield County, Connecticut
وُلِدَ	September 24, 1907 شلبي، نبراسكا
توفي	August 25, 1975 (1975-08-26) (عن عمر 67) Key Biscayne, Florida
الجنسية	أمريكي
اللقب	القنبلة الذرية
الجوائز	Medal for Merit (1946)
السيرة العلمية
المجالات	الفيزياء
أطروحة	The Emission and Scattering of Neutrons (1934)
المشرف على الدكتوراه	George B. Pegram

جون ر. دننگ John R. Dunning ‏(24 سبتمبر 1907 - 25 أغسطس 1975)، عالم فيزياء نووية أمريكي، ساعدت تجاربة في الانشطار النووي على وضع الأساس للقنبلة الذرية. بعد التأكد من انشطار نظير اليورانيوم النادر U235 في تجربة باستخدام كمية مجهرية (0.02 واحد على مليون من الگرام) بقيت صعوبة كبيرة في فصل U235 من U238 الأكثر وفرة. قاد دننج فريق البحث في جامعة كلومبيا الذي درس طريقة الانشطار الغازي لفصل اليورانيوم. هذه العملية كانت مبنية على حجم أصغر قليلاً من جزيئات النظير U235. فحين تُدفع عبر حاجز ذي فجوات، فإن U235 سوف تتحرك بسرعة أكبر، وتكرار هذه العملية عدة مرات سينتج U235 على درجة عالية من النقاء.

The cyclotron built by Dunning in 1939, in the Pupin Hall physics building basement at Columbia University. Dunning (left) is with Enrico Fermi (center) and Dana P. Mitchell (right)

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 حياته اللاحقة

John R. Dunning (left) and Hubert Thelen (right) – first cousins, March 1957 after funeral of John's father A.C. Dunning.

 منشورات مختارة

• John R. Dunning The Emission and Scattering of Neutrons, Phys. Rev. Volume 45, Issue 9, 586–600 (1934). Institutional citation: Department of Physics, Columbia University. Received 5 March 1934.
• H. L. Anderson, E. T. Booth, J. R. Dunning, E. Fermi, G. N. Glasoe, and F. G. Slack The Fission of Uranium, Phys. Rev. Volume 55, Number 5, 511–512 (1939). Institutional citation: Pupin Physics Laboratories, Columbia University, New York, New York. Received 16 February 1939.
• E. T. Booth, J. R. Dunning, and F. G. Slack Delayed Neutron Emission from Uranium, Phys. Rev. Volume 55, Number 9, 876–876 (1939). Institutional citation: Department of Physics, Columbia University, New York, New York. Received 17 April 1939.
• E. T. Booth, J. R. Dunning, and F. G. Slack Energy Distribution of Uranium Fission Fragments, Phys. Rev. Volume 55, Number 10, 981–981 (1939). Institutional citation: Pupin Physics Laboratories, Columbia University, New York, New York. Received 1 May 1939.
• E. T. Booth, J. R. Dunning, and G. N. Glasoe Range Distribution of the Uranium Fission Fragments, Phys. Rev. Volume 55, Issue 10, 982–982 (1939). Institutional citation: Pupin Physics Laboratories, Columbia University, New York, New York. Received 1 May 1939.
• A. O. Nier, E. T. Booth, J. R. Dunning, and A. V. Grosse Nuclear fission of separated uranium isotopes, Phys. Rev. Volume 57, Issue 6, 546–546 (1940). Received 3 March 1940. Booth, Dunning, and Grosse were identified as being at Columbia University, New York, New York. Nier was identified as being at the University of Minnesota, Minneapolis, Minnesota.
• A. O. Nier, E. T. Booth, J. R. Dunning, and A. V. Grosse Further experiments on fission of separated uranium isotopes, Phys. Rev. Volume 57, Issue 8, 748–748 (1940). Received 13 April 1940. Booth, Dunning, and Grosse were identified as being at Columbia University, New York, New York. Nier was identified as being at the University of Minnesota, Minneapolis, Minnesota.
• E. T. Booth, J. R. Dunning, A. V. Grosse, and A. O. Nier Neutron Capture by Uranium (238), Phys. Rev. Volume 58, Issue 5, 475–476 (1940). Received 13 August 1940. Booth, Dunning, and Grosse were identified as being at Columbia University, New York, New York. Nier was identified as being at the University of Minnesota, Minneapolis, Minnesota.
• A. V. Grosse, E. T. Booth, and J. R. Dunning The Fourth (4n+1) Radioactive Series, Phys. Rev. Volume 59, Issue 3, 322–323 (1941). Institutional citation: Pupin Physics Laboratories, Columbia University, New York, New York. Received 11 January 1941.

 ببليوجرافيا

• John R. Dunning Matter, Energy and Radiation (Columbia College Natural Science Series) (McGraw Hill, 1941)
• John R. Dunning and Bruce R. Prentics (editors) Hot Laboratory Operation and Equipment, Volume III. Fifth Hot Laboratories and Equipment Conference (Symposium Publications Division Pergamon Press, 1957)
• John R. Dunning and Bruce R. Prentics (editors) Advances in Nuclear Engineering, Volume I. Proceedings of the Second Nuclear Engineering and Science Conference (Pergamon Press 1957)
• John R. Dunning and Bruce R. Prentics (editors) Advances in Nuclear Engineering, Volume II. Proceedings of the Second Nuclear Engineering & Science Congress (Pergamon Press 1957)

 المراجع

• Anderson, Herbert L. (1989). "John Ray Dunning 1907–1975" (PDF). Biographical Memoirs. National Academy of Sciences. 58: 163–186. Retrieved April 24, 2015. {{cite journal}}: Invalid |ref=harv (help)
• Manhattan District (1947). Manhattan District History, Book II Gaseous Diffusion (K-25) Project, Volume 2 – Research (PDF). Washington, DC: Manhattan District. {{cite book}}: Invalid |ref=harv (help)
• Rhodes, Richard (1986). The Making of the Atomic Bomb. London: Simon & Schuster. ISBN 0-671-44133-7. {{cite book}}: Invalid |ref=harv (help)