Use of Counter Tubes in X-Ray Analysis

Abstract

The more important properties of end-window Geiger counters, side-window proportional counters, and NaI(Tl) scintillation counters are reviewed and their performance in the 5 to 50 kvp x-ray analysis region is compared. Proportional and scintillation counters have resolving times of the order of 0.25 μsec and virtually eliminate the nonlinearity limitation of the Geiger counter. They produce pulse amplitudes proportional to the energy of the x-ray quanta, and thus simple pulse height discrimination techniques can be used to obtain greatly improved peak-to-background ratios with little loss of intensity of the characteristic x-rays. They are as reliable and nearly as easy to use as Geiger counters. The electronic discrimination method is described and explained with some practical applications. For a given experimental arrangement, the measured intensity is determined by the quantum counting efficiency of the counter tube, and the peak-to-background ratio is determined by the spectral response of the detector-discriminator combination.