Arnold Flammersfeld

Arnold Flammersfeld (born February 10, 1913 in Berlin ; † January 5, 2001 in Icking ) was a German physicist and university professor.

Flammersfeld studied physics from 1931 to 1937 at the Friedrich Wilhelms University (since 1949 Humboldt University ) in Berlin . From 1937 Flammersfeld was Lise Meitner's research assistant at the Kaiser Wilhelm Institute for Chemistry in Berlin-Dahlem , whose third department was headed by Otto Hahn and Lise Meitner. This department was one of the leading nuclear physics institutes. Here Flammersfeld did his doctorate in 1938 under Lise Meitner with a measurement of the beta spectrum of the bismuth isotope ²¹⁰ Bi, which the theory of beta decay could only interpret many years later. A few months later, Lise Meitner had to leave Germany. Flammersfeld kept in touch with her by letter and reported on the progress of his spectroscopic work.

Flammersfeld worked on the German “ uranium project ” from 1939 to 1945 , initially for two years under Walther Bothe at the Institute for Physics at the Kaiser Wilhelm Institute for Medical Research (since 1948 Max Planck Institute for Medical Research ) in Heidelberg , then again at the Dahlem Institute, which was relocated to Tailfingen (Württemberg) in 1943 . In Heidelberg he worked with Bothe on fission and resonant neutron capture in natural uranium , and he also studied the products of uranium fission. With a double ionization chamber he was able to demonstrate the “two-hump structure” in the energy and mass structure of the fissure fragments. In Tailfingen, Flammersfeld began experiments at a small particle accelerator to generate isomeric atomic nuclei , which then formed his most important field of work for a long time. From there, Flammersfeld completed his habilitation in Tübingen in 1947 , was a private lecturer here and moved to the Max Planck Institute for Chemistry in Mainz in 1949 . Above all, the isomer experiments were continued here and expanded to include the measurement of coefficients for converted radiation transitions. Together with Josef Mattauch, he published the "Isotope Report", which was decisive for a long time.

In 1954, Arnold Flammersfeld succeeded Hans Kopfermann as director of the Second Physics Institute at the Georg-August University in Göttingen . There he built a modern institute for nuclear physics . First of all, the production and spectroscopy of isomeric atomic nuclei was continued at a 1 MV pressure tank cascade accelerator and expanded through the use of scintillation detectors for electrons and photons , which were new at the time . Then in 1958 I was offered the position of physical director at the Hahn-Meitner-Institut in Berlin-Wannsee . However, Flammersfeld decided to stay in Göttingen. As a result, the Göttingen Institute was significantly enlarged and a large accelerator came to Göttingen. The synchrocyclotron was primarily used for isotope production . Pure sources for the extensively operated decay spectroscopy were produced on the machine and in the newly installed radiochemical laboratory . The direct generation of gaseous sources in the internal jet and the rapid transport of radioactive nuclei in aerosols in noble gas jets played an important role . The internal cyclotron beam was suitable for the production of strong monochromatic photon sources with which u. a. the first evidence of dispersive Delbrück scattering was successful. This effect, which was predicted in 1933 at the Dahlem Institute, is based on the vacuum polarization , which gives the Coulomb field of heavy nuclei a refractive index .

In addition to research, Arnold Flammersfeld's main concern was academic teaching, especially the training of students in large internships. The Göttingen Academy of Sciences elected Flammersfeld as a member in 1956. In 1961/62 he was rector of the University of Göttingen . In 1978 he retired.

Works

• A precise determination of the continuous beta spectrum of the RaE - Jena, 1938
• Isomers to stable nuclei in rhodium, silver, dysprosium and hafnium - 1946
• Isotope report - together with Josef Mattauch , Tübingen, 1949
• Problems of Today's Atomic Physics , Göttingen, 1962