The First International Cosmic Ray Conference

Abstract

The first of a series of International Cosmic Ray Conferences organised by the IUPAP Cosmic Ray Commission took place in Cracow (Poland) more than 30 years ago, from October 6 to 11, 1947. Professor J. Clay (Fig. 1), the famous discoverer of the geomagnetic effects, was the chairman of the Cosmic Ray Commission and P. Auger (Fig. 2) was the secretary. One may say that the Conference took place in the historical period when, in cosmic ray physics, a new fundamental branch of science, Elementary Particle Physics in the present meaning first came into existence. The participants of that Conference will never forget the historical report of Cecil Frank Powell entitled in the Conference schedule “Evidence for the Existence of Mesons of Different Mass”. It was one of the first reports on the discovery of π-mesons (Fig. 3). However, also at that Conference, Professor Leprince-Ringuet (Fig. 1) in his report “Estimations et measures des masses de mesóns” presented examples of particles with masses about 1000 times that of an electron. So, K-mesons were also presented at the Cracow-Conference.