The Institute of Physics in the Post-war Period : Part 2: Some Highlights on Research in the Post-war Period

Soon after the end of WWII, the cosmic ray physics group started again their researches with cloud chambers and counters on some locations on the Alps. Their researches culminated with the construction of the huge multi-plate cloud chamber, built by Fiorini, Giacconi and Succi, and used on the Alps. Among the results obtained by them was the observational proof of the non-existence of the varytrons erroneously discovered by Alikhanian. Another group working on cosmic ray physics started with Occhialini’s arrival to Milan. He created an international group, working in strict collaboration with other other groups in Italy and abroad, with nuclear emulsions exposed to cosmic radiation on balloons. The Milan group was an important member of the G-stack collaboration, with the exposition of a giant stack of emulsions to cosmic rays for the study of mesons, strange particles and hyperons, and of the K−-collaboration with the exposition of a stack to artificially produced particles at the Bevatron for the study of strange particles. Nuclear physics research was carried on in particular in collaboration with the CISE and the INFN. An important field of research was the theoretical study of nuclear reactors. Carlo Salvetti and Sergio Gallone developed solutions of the equations for the transient regime and the working conditions of nuclear reactors. The experimental study was based on electrostatic machines built at the CISE and INFN. Theoretical physics researches covered a wide range of topics, from the phenomenology of cosmic rays to the ergodic conditions in quantum theory. An interesting research group was that of solid state physics, one of the first in Italy, founded by Fumi.