MEASUREMENT OF THE IONIZATION YIELD OF LOW ENERGY ATOMIC PARTICLES IN GASES

The purpose of this investigation was to study the total ionization yield of charged atomic particles in gases for energies in the range of a few to 250 kev. A large cylindrical ionization chamber was used for this study. The charged particles were selected from the kevatron beam by a magnetic and an electrostatic analyzer and entered the chamber by means of a 0.004 inch diameter open window. A differential pumping system permitted pressures up to 10 mm Hg to be maintained in the chamber. The chamber was alternately operated as a proportional counter and an ionization chamber to measure the rate with which the primary items entered the chamber and the ionization produced by them, respectively. A detailed description of the apparatus and measuring technique are given.