Edoardo Amaldi - Böcker

The physicist Friedrich Houtermans (1903-1966) was an essential promoter and proponent of the development of physics in Berne. He introduced a number of activities in the field of elementary particles, with a special focus on the physics of cosmic rays, and important contributions in applied physics. This biography of Houtermans was written by Edoardo Amaldi and was almost finished just before his unexpected death in 1989. The editors have only corrected typographical errors and have introduced only minimal text changes in order to preserve the original content. Additionally they have collected and included unpublished pictures and memories from Houtermans’ students and collaborators. The text is the result of a thorough and intensive study on Houtermans’ life and character carried out by Edoardo Amaldi. It is more than a biography, since the figure of Houtermans is set in a historical perspective of Europe between the two world wars. This book will be of great interest to historians and historians of science.

661 tures, such as occurs in stellar atmospheres and in thermonuc1ear processes, will not be considered 1. Because photoelectric absorption predominates completely at low photon energies, and penetration theory is elementary under these conditions, attention is directed in this artic1e to photon energies above ""20 kev. On the high energy side, this artic1e does not cover the cascade shower processes which are dealt 2 with in cosmic ray studies • In this connection it is recalled that the cascade shower process, which involves electrons and positrons besides X rays, becomes predominant above 10 Mev in heavy elements, and above 100 Mev in light ones. Theories developed for the study of cascade showers in cosmic rays rely on assumptions about the prob ability of interactions with matter which are adequate only at energies of the order of 1 Gev or more. Below this energy there is a gap in which penetration phenomena are qualitatively known and understood but have not yet been calculated in detail. A few detailed experimental studies which have been made at energies up to 300 Mev will be reviewed in this article.