A method for the measurement of the absolute value of the average energy to produce an ion pair in noble gases with X-rays

A method is described that allows the measurement of the absolute value of the average energy to produce an ion pair in noble gases for soft X-rays and its energy dependence. It uses a specially designed gas proportional scintillation counter working under electric fields below the ionization threshold. The spectrum of the radiation absorbed, and thus the number of photons detected at each energy for a period of time of the order of a minute, are measured with the scintillation counter, and at the same time the total primary electron charge produced is collected in one of the grids and measured with an electrometer.<>