In 1938 Greisen graduated with a B.S. from Franklin & Marshall College.[3] In 1942 Greisen earned his PhD in physics at Cornell University under Bruno Rossi with thesis Intensity of cosmic rays at low altitude and the origin of the soft component. He worked on the Manhattan Project from 1943 to 1946 in Los Alamos, where he was a group leader. In 1945 he was an eyewitness to the Trinity test as a member of the detonation team. After his Los Alamos work, he returned to Cornell University in 1946 as an assistant professor of physics. From 1975 he was a professor of astronomy and from 1976 to 1979 chair of the astronomy department and from 1978 to 1983 dean of faculty. In 1986 he retired as professor emeritus. From 1975 to 1981 he was adjunct professor at the University of Utah.
Elizabeth Greisen's Los Alamos badge
His wife, Elizabeth, also worked on the Manhattan Project.[4]
Greisen did experiments on cosmic ray- and gamma ray-astronomy using high-altitude balloons. In 1971 he and his colleagues discovered pulsed gamma rays with energies greater than 200 MeV from the pulsar in the Crab Nebula. In 1966 he published the theory of the GZK cutoff, independently of the Russians Georgiy Zatsepin and Vadim Kuzmin who in 1966 also published their version of the same theory.
In 1966 he joined the AAS. In 1969 he was one of the founders of the Section for High Energy Astrophysics Division of the AAS and, in 1970 and 1971, was the first chair of this division. At Cornell University in 1969 he led a group of faculty members who modernized the university's physics curriculum.[5]
Rossi and Greisen built an apparatus, centered around a Geiger-Müller counter, to distinguish the altitude dependence of hard (mesotron, i.e.muon) and soft (electron) cosmic ray secondaries. The goal of Rossi and Greisen was to confirm that the lifetimes of the muons depended upon their energy as predicted by the theory of special relativity. The data presented in Greisen's thesis was taken at altitudes of 249,1616, 3240, and 4300 meters at Echo Lake, Colorado. Greisen's thesis work was cited many times over the ensuing decades.[6]
Trinity test eyewitnessedit
"From 1943 to 1946 Greisen was a member of the group of physicists who worked on the Manhattan Project at Los Alamos. As one of the leaders of the denotation team, he was an observer at the Trinity test on 16 July 1945. His eyewitness report of that world-changing event is an important historical document. His comment "My God! It worked!" was typical of him."[2][7]
Worksedit
with Bruno Rossi: Rossi, Bruno; Greisen, Kenneth (1941). "Cosmic-ray theory". Reviews of Modern Physics. 13 (4): 240–309. Bibcode:1941RvMP...13..240R. doi:10.1103/RevModPhys.13.240.
Greisen, Kenneth (1966). "End of the cosmic-ray spectrum?". Physical Review Letters. 16 (17): 748–750. Bibcode:1966PhRvL..16..748G. doi:10.1103/PhysRevLett.16.748. (GZK-Cutoff)
Referencesedit
^birth dates and career information on American Men and Women of Science, Thomson Gale 2004
^Gold, Lauren (April 2, 2007). "Cornell physicist Kenneth Greisen, cosmic ray scientist and Manhattan Project participant, dies at 89". Cornell Chronicle.
^"Elizabeth Greisen - Nuclear Museum". ahf.nuclearmuseum.org/. Retrieved 7 August 2023.
^Greisen, Eric W. (2007). . Bulletin of the American Astronomical Society. 39 (4): 1059. Bibcode:2007BAAS...39.1059G. Archived from the original on 2013-01-18.
^Kimble, Virginia (2011). "Kenneth Greisen" (PDF). Biographical Memoirs, National Academy of Sciences. pp. 1–26.
^Trinity Test, July 16, 1945 - Eyewitness Accounts
kenneth, greisen, this, article, multiple, issues, please, help, improve, discuss, these, issues, talk, page, learn, when, remove, these, template, messages, this, article, needs, additional, citations, verification, please, help, improve, this, article, addin. This article has multiple issues Please help improve it or discuss these issues on the talk page Learn how and when to remove these template messages This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Kenneth Greisen news newspapers books scholar JSTOR January 2013 Learn how and when to remove this template message This article includes a list of general references but it lacks sufficient corresponding inline citations Please help to improve this article by introducing more precise citations January 2013 Learn how and when to remove this template message Learn how and when to remove this template message Kenneth Ingvard Greisen 24 January 1918 in Perth Amboy New Jersey 17 March 2007 in Ithaca New York 1 was an American physicist who worked on nuclear physics and the astrophysics of cosmic rays and gamma radiation He will be most remembered for his realization that the cosmic microwave background limits the high energy end of the spectrum of cosmic ray protons 2 Greisen s photo on his security badge at Los Alamos Contents 1 Career 2 Greisen s PhD thesis 3 Trinity test eyewitness 4 Works 5 References 6 External links 6 1 Archival collectionsCareer editIn 1938 Greisen graduated with a B S from Franklin amp Marshall College 3 In 1942 Greisen earned his PhD in physics at Cornell University under Bruno Rossi with thesis Intensity of cosmic rays at low altitude and the origin of the soft component He worked on the Manhattan Project from 1943 to 1946 in Los Alamos where he was a group leader In 1945 he was an eyewitness to the Trinity test as a member of the detonation team After his Los Alamos work he returned to Cornell University in 1946 as an assistant professor of physics From 1975 he was a professor of astronomy and from 1976 to 1979 chair of the astronomy department and from 1978 to 1983 dean of faculty In 1986 he retired as professor emeritus From 1975 to 1981 he was adjunct professor at the University of Utah nbsp Elizabeth Greisen s Los Alamos badgeHis wife Elizabeth also worked on the Manhattan Project 4 Greisen did experiments on cosmic ray and gamma ray astronomy using high altitude balloons In 1971 he and his colleagues discovered pulsed gamma rays with energies greater than 200 MeV from the pulsar in the Crab Nebula In 1966 he published the theory of the GZK cutoff independently of the Russians Georgiy Zatsepin and Vadim Kuzmin who in 1966 also published their version of the same theory In 1966 he joined the AAS In 1969 he was one of the founders of the Section for High Energy Astrophysics Division of the AAS and in 1970 and 1971 was the first chair of this division At Cornell University in 1969 he led a group of faculty members who modernized the university s physics curriculum 5 In 1974 he was elected to the U S National Academy of Sciences Greisen s PhD thesis editRossi and Greisen built an apparatus centered around a Geiger Muller counter to distinguish the altitude dependence of hard mesotron i e muon and soft electron cosmic ray secondaries The goal of Rossi and Greisen was to confirm that the lifetimes of the muons depended upon their energy as predicted by the theory of special relativity The data presented in Greisen s thesis was taken at altitudes of 249 1616 3240 and 4300 meters at Echo Lake Colorado Greisen s thesis work was cited many times over the ensuing decades 6 Trinity test eyewitness edit From 1943 to 1946 Greisen was a member of the group of physicists who worked on the Manhattan Project at Los Alamos As one of the leaders of the denotation team he was an observer at the Trinity test on 16 July 1945 His eyewitness report of that world changing event is an important historical document His comment My God It worked was typical of him 2 7 Works editwith Bruno Rossi Rossi Bruno Greisen Kenneth 1941 Cosmic ray theory Reviews of Modern Physics 13 4 240 309 Bibcode 1941RvMP 13 240R doi 10 1103 RevModPhys 13 240 Greisen Kenneth 1966 End of the cosmic ray spectrum Physical Review Letters 16 17 748 750 Bibcode 1966PhRvL 16 748G doi 10 1103 PhysRevLett 16 748 GZK Cutoff References edit birth dates and career information on American Men and Women of Science Thomson Gale 2004 a b David Cassel Edith Cassel Donald Holcomb 2007 Kenneth Ingvard Gresien Phys Today 60 7 78 79 Bibcode 2007PhT 60g 78C doi 10 1063 1 2761816 Gold Lauren April 2 2007 Cornell physicist Kenneth Greisen cosmic ray scientist and Manhattan Project participant dies at 89 Cornell Chronicle Elizabeth Greisen Nuclear Museum ahf nuclearmuseum org Retrieved 7 August 2023 Greisen Eric W 2007 Obituary Kenneth Ingvard Greisen Bulletin of the American Astronomical Society 39 4 1059 Bibcode 2007BAAS 39 1059G Archived from the original on 2013 01 18 Kimble Virginia 2011 Kenneth Greisen PDF Biographical Memoirs National Academy of Sciences pp 1 26 Trinity Test July 16 1945 Eyewitness AccountsExternal links editObituary from Cornell UniversityArchival collections edit Kenneth I Greisen course notes 1959 1960 Niels Bohr Library amp Archives Retrieved from https en wikipedia org w index php title Kenneth Greisen amp oldid 1170346331, wikipedia, wiki, book, books, library,
