Justus Mühlenpfordt

In 1935, Mühlenpfordt, went to work for Gustav Hertz at Siemens. Among other things, Mühlenpfordt's research activities involved x-rays; an x-ray tube with a cross-shaped anode was named after him.[4] Hertz conducted research activities in isotope separation, which effected Mühlenpfordt's career interests.

How Mühlenpfordt got to the Soviet Union and his activities there are best understood in the context of four prominent Berlin scientists. Manfred von Ardenne, director of his private laboratory Forschungslaboratoriums für Elektronenphysik,[5] Gustav Hertz, Nobel laureate and director of Research Laboratory II at Siemens, Peter Adolf Thiessen, ordinarius professor at the Humboldt University of Berlin and director of the Kaiser-Wilhelm-Institut für Physikalische Chemie und Elektrochemie in Berlin-Dahlem, and Max Volmer, ordinarius professor and director of the Physical Chemistry Institute at the Berlin Technische Hochschule, had made a pact. The pact was a pledge that whoever first made contact with the Soviets would speak for the rest. The objectives of their pact were threefold: (1) Prevent plunder of their institutes, (2) Continue their work with minimal interruption, and (3) Protect themselves from prosecution for any political acts of the past.[6] Before the end of World War II, Thiessen, a member of the Nationalsozialistische Deutsche Arbeiterpartei, had Communist contacts.[7] On 27 April 1945, Thiessen arrived at von Ardenne's institute in an armored vehicle with a major of the Soviet Army, who was also a leading Soviet chemist.[8] All four of the pact members were taken to the Soviet Union along with colleagues from their institutes. Hertz was made head of Institute G, in Agudseri (Agudzery),[9][10] about 10 km southeast of Sukhumi and a suburb of Gul’rips (Gulrip’shi). Topics assigned to Gustav Hertz's Institute G included: (1) Separation of isotopes by diffusion in a flow of inert gases, for which Gustav Hertz was the leader, (2) Development of a condensation pump, for which Justus Mühlenpfordt was the leader, (3) Design and build a mass spectrometer for determining the isotopic composition of uranium, for which Werner Schütze was the leader, (4) Development of frameless (ceramic) diffusion partitions for filters, for which Reinhold Reichmann was the leader, and (5) Development of a theory of stability and control of a diffusion cascade, for which Heinz Barwich was the leader;[11][12] Barwich had been deputy to Hertz at Siemens.[13] Other members of Institute G were Werner Hartmann, Werner Schütze[14] and Karl-Franz Zühlke.[15] Von Ardenne was made head of Institute A,[16][17] in Sinop,[9][10] a suburb of Sukhumi. Volmer went to the Nauchno-Issledovatel’skij Institut-9 (NII-9, Scientific Research Institute No. 9),[18] in Moscow; he was given a design bureau to work on the production of heavy water.[19] In Institute A, Thiessen became leader for developing techniques for manufacturing porous barriers for isotope separation.[20]

After Mühlenpfordt's successful work at Institute G, he became chief of a design bureau in Leningrad, no earlier than 1950.[19]

In preparation for release from the Soviet Union, it was standard practice to put personnel into quarantine for a few years if they worked on projects related to the Soviet atomic bomb project. Mühlenpfordt spent his quarantine at a facility in Agudzery (Agudseri), as did other German scientists. Additionally, in 1954, in preparation sending the German scientists to the Deutsche Demokratische Republik (DDR, German Democratic Republic), the DDR and the Soviet Union prepared a list of scientists they wished to keep in the DDR, due to their having worked on projects related to the Soviet atomic bomb project; this list was known as the "A-list". On this A-list were the names of 18 scientists; nine, possibly 10, of the names were associated with the Nikolaus Riehl group which worked at Plant No. 12 in Ehlektrostal' (Электросталь[21]). Mühlenpfordt was on the list.[15][22][23]

Mühlenpfordt arrived in the DDR in 1955. He was appointed director of the Institut für physikalische Stofftrennung of the Academy of Sciences, in Leipzig; in 1964, the institute was renamed the Institut für stabile Isotope (Institute for Stable Isotopes). In 1960, he was also appointed a professor of the Academy of Sciences. In 1968, he was additionally appointed Beauftragter (Representative) of the Academy of Sciences.[3][24]

From 1969 until his retirement in 1974, Mühlenpfordt was director of the Forschungsbereiches Kern- und Istopentechnik der Akademie der Wissenschaften (Research Division for Nuclear and Isotope Technology of the Academy of Sciences); the organization was later renamed the Forschungsbereich Kernwissenschaften der Akademie der Wissenschaften (Nuclear Science Research Division of the Academy of Sciences), and still later renamed the Forschungsbereich Physik der Akademie der Wissenschaften (Physics Research Division of the Academy of Sciences).[3][4]

Upon his retirement, Mühlenpfordt devoted his interests to art, history, and philosophy, while still retaining active interests in scientific research – improvement of television and investigating methods of earthquake prediction.[4]