Further Examination of Theories relating the Absorption of Gamma-ray Energy in a Medium to the Ionization produced in a Cavity

Abstract

Experimental tests of cavity ionization theories previously performed at 1.25 Mev photon energy were extended to energies of 0.66 and 0.41 Mev. The variation of ionization with pressure, with atomic number of the gas, and with the atomic number of the chamber wall agreed more closely with the theory of Spencer and Attix than with that of Gray. Although the measurements in hydrogen at low pressures were probably affected by outgassing from the chamber walls, the predominant cause of the deviation from theory is thought to be the transfer of slow electrons between electodes.