Ionization of Air by Alpha- and Beta-Rays as a Function of Pressure

Abstract

Measurements of ionization of air by alpha-particles from polonium and by beta-rays excited by gamma-rays, were made under usual laboratory conditions. The ionization by beta-rays increased at a decreasing rate with increase in pressure, in accordance with results obtained in previous investigations. The ionization by alpha-particles decreased with increasing pressure, at first rapidly, then more slowly until, at 80 atmospheres, the value was approximately 5 percent of that at atmospheric pressure.