Directors and research fellows from 1949 until 1953

Fritz Straßmann (1902-1980) held the position of Director of the Radiochemistry Department (formerly known as the Hahn Department) from 1949. He continued the work started in Berlin and furthered in Tailfingen at the MPI in Mainz. In the working rooms, which were built in 1947, he conducted radiochemical studies and worked on issues relating to nuclear physics and the structure of atomic nuclei. Among other things, he also performed biological and medical research using radioactive indicators. Thanks to the installation of two high-voltage systems (a 1.4 mV cascade generator and a 3 mV Van De Graaff generator), the department was able to create radioactive preparations for a multitude of research purposes at the start of the 1950s. In 1953, Fritz Straßmann ended his active work at the Institute and dedicated his energies to the Johannes Gutenberg University, where he had been appointed the first Professor of Chemistry in 1946.

Josef Mattauch (1895-1976), who succeeded Lise Meitner as head of the Physics Department of the Kaiser Wilhelm Institute for Chemistry in 1941, was appointed Director of the Institute in 1947 (succeeding Otto Hahn). After spending time abroad in Switzerland and the US, in 1952 Mattauch and his staff used mass spectrography to continue the precise determinations of isotope masses, which was started in Berlin. They measured the isotopic abundancies on various elements and precisely determined the nuclear masses of neutrons, protons and chlorine. Later on, they used sensitive mass spectrometers to determine extremely small quantities of noble gases in meteorites. Josef Mattauch retired in 1965.

Friedrich A. Paneth (1887-1958) succeeded Straßmann as head of the Radiochemistry Department in 1953. He also brought to the Institute a new area of research – cosmochemistry. This department researched the fission products of iron and other elements generated as a result of high-energy cosmic radiation in meteorites. It also used the helium method to perform age dating and measure extremely small quantities of the noble gases helium and neon in iron meteorites and metallic iron (generated on Earth). Friedrich Paneth died in 1958, just five years after taking up his position.