A METHOD FOR THE MEASUREMENT OF THE ABSOLUTE VALUE OF W FOR X-RAYS INNOBLE-GASES - RESULTS AT 5.9 KEV IN XENON

A method is described that allows the measurement of the absolute valu e of the average energy to produce an ion pair, w, in noble gases for soft X-rays and its energy dependence. it uses a specially designed ga s proportional scintillation counter working under electric fields bel ow the ionization threshold. The spectrum of the radiation absorbed, a nd so the number of photons detected at each energy for a period of ti me of the order of the minute, is measured with the scintillation coun ter and at the same time the total primary electron charge produced is collected in one of the grids and measured with an electrometer. For pure xenon at 1030 mbar a value of w = 24.2 +/- 2.5 eV was measured wi th 5.9 keV X-rays.