THE ENERGY DISTRIBUTION OF ELECTRONS FROM IONIZING COLLISIONS OF HEAVY PARTICLES

摘要

The energy distribution of electrons produced in ionizing collisions of ions and fast atoms or molecules with the atoms or molecules of a gas at rest have been measured for hydrogen, nitrogen, argon, and helium. The energy of the incident particles ranged from 0.30 to 3-0 kev. The electrons released at 90° with the in¬cident ion or atom beam were analyzed in an electrostatic energy selector which con¬sisted of 90° segments of coaxial cylinders. The use of a fine wire grid in the region in which ionization occurs allowed a positive differentiation to be made between the ionization electrons and secondary electrons from any metal surfaces. For the molecular and atomic ions and neutral particles of hydrogen the yield decreases rapidly from a maximum at zero energy to an energy of about five electron volts and then more slowly afterward. Little difference exists between the distributions for charged and uncharged atomic and molecular incident particles. The results in nitrogen are similar to those in hydrogen. An increase in the energy of relative motion increases the over-all yield as well as the relative number of fast electrons.