Peter Herbert Jensen

Peter Herbert Jensen (1913 – 1955) was a German experimental nuclear physicist. During World War II, he worked on the German nuclear energy project, known as the "Uranverein". After the war, he was a department director in the high-voltage section of the Max Planck Institute for Chemistry, in Mainz, and a supernumerary professor University of Mainz.

Education

From 1932 to 1938, Jensen studied at the "Universität Göttingen" and the " Albert-Ludwigs-Universität Freiburg". He received his doctorate in 1938, under Georg Joos at the University of Göttingen. [ Hentschel and Hentschel, 1996, Appendix F; see the entry for Peter Jensen.]

Career

In 1938, Jensen was a volunteer in Walther Bothe's "Institut für Physik" at the "Kaiser-Wilhelm Institut für medizinische Forschung" (KWImF, Kaiser Wilhelm Institute for Medical Research, reorganized and renamed in 1948 the Max-Planck Institut für medizinische Forschung), in Heidelberg. He was a teaching assistant there to Walther Bothe from 1939 to 1946. During this time, Jensen worked on the German nuclear energy project, also known as the "Uranverein" (Uranium Club); his work with Walther Bothe, Arnold Flammersfeld, and Wolfgang Gentner appeared as Internal Reports in the "Kernphysikalische Forschungsberichte" ("Research Reports in Nuclear Physics") . Jensen completed his Habilitation at the " Ruprecht-Karls-Universität Heidelberg" in 1943. The subject of his Habilitationsschrift was on nuclear cross sections of neutron scattering experiments conducted at the University of Heidelberg. [ Hentschel and Hentschel, 1996, Appendix F; see the entry for Peter Jensen.]

In the latter years of World War II, Berlin scientific organizations moved equipment and personnel out of the city to escape effects of Allied air raids. The "Kaiser-Wilhelm Institut für Physik" (KWIP, Kaiser Wilhelm Institute for Physics) had partly evacuated to Hechingen and Haigerloch in southern Germany. The "Uranmaschine" (nuclear reactor) B 8 (B-VIII) was constructed in Haigerloch. The construction of the reactor utilized 1.5 tons of heavy water, 1.5 tons of uranium, and 10 tons of graphite. The configuration was uranium in the form of cubes (40 chains of 9 cubes each and 38 chains of 8 cubes each) in heavy water surrounded by graphite. The report on the B 8 experiment was written by Fritz Bopp, Erich Fischer, Werner Heisenberg, and Karl Wirtz from the KWIP and Walther Bothe, Peter Jensen, and Oskar Ritter from the KWImF. [ Hentschel and Hentschel, 1996, 377 and 377n73.] [ "Bericht über den Versuch B₈ in Haigerloch", as cited in Hentschel and Hentschel, 1996, 377n73.] [ Walker, 1993, 103 and 152.]

From 1946 to 1953, Jensen was Wolfgang Gentner’s teaching assistant at the University of Freiburg; from 1953 to 1954 he was a senior assistant there. From 1947 he was a lecturer, and from 1951 he was a supernumerary professor (nichtplanmäßiger Professor) focusing on the installation of a Van de Graaff generator for experiments in nuclear physics. [ Hentschel and Hentschel, 1996, Appendix F; see the entry for Peter Jensen.]

From 1954, he was a department director in the high-voltage section of the " Max-Planck Institut für Chemie - Otto Hahn Institut", in Mainz, and he was a supernumerary professor at the " Johannes Gutenberg-Universität Mainz". [ Hentschel and Hentschel, 1996, Appendix F; see the entry for Peter Jensen.]

Internal Reports

The following reports were published in "Kernphysikalische Forschungsberichte" ("Research Reports in Nuclear Physics"), an internal publication of the German " Uranverein". The reports were classified Top Secret, they had very limited distribution, and the authors were not allowed to keep copies. The reports were confiscated under the Allied Operation Alsos and sent to the United States Atomic Energy Commission for evaluation. In 1971, the reports were declassified and returned to Germany. The reports are available at the Karlsruhe Nuclear Research Center and the American Institute of Physics. [ Hentschel and Hentschel, 1996, Appendix E; see the entry for "Kernphysikalische Forschungsberichte".] [ Walker, 1993, 268-274.]

*Arnold Flammersfeld, Peter Jensen, Wolfgang Gentner "Die Energietönung der Uranspaltung" G-25 (21 May 1940)

*Arnold Flammersfeld, Peter Jensen, Wolfgang Gentner "Die Aufteilungsverhältnisse und Energietönung bei der Uranspaltung" G-26 (24 September 1940)

*Walther Bothe and Peter Jensen "Die Absorption thermischer Neutronen in Elektrogrphit" G-71 (20 January 1941)

*Walther Bothe and Peter Jensen "Resonanzeinfang an einer Uranoberfläche" G-72 (12 May 1941)

*Peter Jensen "Eine weitere Bestimmung des Absorptionsquerschnittes von 38 ["Präparat 38", "38-Oxyd", and "38" were the cover names for uranium oxide; see [http://www.deutsches-museum.de/archiv/archiv-online/geheimdokumente/forschungszentren/leipzig/schichtenanordnung-h2o/ Deutsches Museum] .] für thermische Neutronen" G-98 (28 July 1941)

Selected literature

* W. Bothe and P. Jensen "Die Absorption thermischer Neutronen in Kohlenstoff", "Zeitschrift für Physik" Volume 122, Issues 9-12, 749-755 (1944). Received on 21 January 1944. Institutional affiliation: "Institut für Physik am Kaiser Wilhelm-Institut für medizinische Forschung, Heidelberg". (As cited in Hentschel and Hentschel, 1996, 370n43, this paper has a footnote stating that the paper was written in July 1940.)

* Peter Jensen "Die Bremsung von Neutronen in Kohlenstoff, Wasser und schwerem Wasser", "Zeitschrift für Physik" Volume 122, Issues 9-12, 756-768 (1944). Received on 21 January 1944. Institutional affiliation: "Institut für Physik am Kaiser Wilhelm-Institut für medizinische Forschung, Heidelberg". (As cited in Hentschel and Hentschel, 1996, 366n24, this paper has a footnote stating that the paper was written in July 1940.)

* Helmut Steinwedel, J. Hans D. Jensen, and Peter Jensen "Nuclear Dipole Vibrations", "Phys. Rev." Volume 79, Issue 6, 1019 - 1019 (1950). Institutional affiliations: Steinwedel and J. H. D. Jensen - "Institut für theoretische Physik, Universität Heidelberg" and Peter Jensen - "Physikalisches Institut, Universität Freiburg". Received 10 July 1950.

Bibliography

* Hentschel, Klaus (editor) and Ann M. Hentschel (editorial assistant and translator) "Physics and National Socialism: An Anthology of Primary Sources" (Birkhäuser, 1996) ISBN 0-8176-5312-0

* Walker, Mark "German National Socialism and the Quest for Nuclear Power 1939–1949" (Cambridge, 1993) ISBN 0-521-43804-7

Notes