Measurement of the Fano-factor in tissue-equivalent and other gases

Measurements of pulse height spectra of very low energy radiation in a proportional counter filled with a polyatomic gas or mixture of gases proved to be an ample source of valuable information on gas properties as well as on some basic physical processes. For example, it is possible to calculate the energy required to form an ion pair in a gas, to study the gas multiplication phenomena and to calculate the probability distribution function of primary ionization charges. This report also deals with a basic physical property of gases when irradiated with low energy radiation: the Fano factor which determines the width of the primary ionization charge distribution