Post-war reconstruction in Milan: The three accelerators.

While Giovanni Gentile jr and Giovanni Polvani showed some interest in planning an accelerator for the Institute of Physics of Milan University already before the post-war reconstruction (actually a new construction) --- $e.g.$ with the suggestion to Giorgio Salvini to study a feasibility project of a betatron --- the actual possibility of building a machine in Milan only materialized in the post-war period. The Institute of Physics and two research institutions very closely connected to it such as CISE and INFN managed to equip themselves with accelerators for theoretical and applicative research in nuclear physics: the CISE Cockcroft-Walton and the INFN linear accelerator in the 1950s, and the cyclotron of the Institute of Physics in the 1960s. The aim of this report is to describe the historical-scientific context that saw the creation of these new research tools in close connection with the developing interests of the Lombard industrial environment.