Ernst Rexer

Ernst Rexer (2 April 1902 – 14 May 1983) was a German nuclear physicist and a professor of physics at the Dresden University of Technology.

Initially part of the German Uranverein, he was one of many German nuclear physicists at the Soviet program of nuclear weapons while in Soviet custody in Russia until his repatriation to Germany in 1956. Biography Education

According to the German edition of Wikipedia, Rexer was born in Stuttgart, Baden-Württemberg, on 2 April 1902. After completing his high schooling in 1921, he enrolled in University of Freiburg to study physics and chemistry; he passed his chemist association's exam in 1926. From 1926 to 1929, he found an employment with the Osram Licht AG where he worked on their glass technology laboratories in Berlin and in Weißwasser.

While Rexer was at the PTR, some of the research was carried out at the Versuchsstelle (testing station) of the HWA in Gottow; Kurt Diebner, was director of the facility. The testing station is where Rexer, F. Berkei, W. Borrmann, W. Czulius, Kurt Diebner, Georg Hartwig, Karl-Heinz Höcker, Walter Herrmann, and Heinz Pose, compared the effectiveness of neutron production in a paraffin-moderated reactor using uranium plates, rods, and cubes. Internal reports (See section below: Internal Reports.) on their activities were classified Top Secret and had limited distribution. The G-1 experiment performed at the HWA testing station had lattices of 6,800 uranium oxide cubes (about 25 tons) in the neutron moderator paraffin. Their work verified Höcker's calculations that cubes were better than rods, and rods were better than plates.

In 1944, Rexer was appointed professor at the Physikalischen Institut (Physics Institute) at the Universität Leipzig.

On 5 March 1946, in order to staff his laboratory, Pose and NKVD General Kravchenko, along with two other officers, went to Germany for six months to hire scientists. Additionally, Pose procured equipment from the companies AEG, Zeiss, Schott Jena, and Mansfeld, which were in the Russian occupation zone.

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.

F. Berkei, W. Borrmann, W. Czulius, Kurt Diebner, Georg Hartwig, K. H. Höcker, W. Herrmann, H. Pose, and Ernst Rexer Bericht über einen Würfelversuch mit Uranoxyd und Paraffin (dated before 26 November 1942). G-125. Heinz Pose and Ernst Rexer Versuche mit verschiedenen geometrischen Anordnungen von Uranoxyd und Paraffin (12 October 1943). G-240.

Selected literature

Ernst Rexer Additive Verfärbung von Alkalihalogenidkristallen II. Ultramikroskopische Diffusionsbefunde, Zeitschrift für Physik Volume 76, Numbers 11–12, 735–755, (1932). Institutional affiliation: Institut für theoretische Physik, Halle, Saale. The article was received on 12 May 1932.