Use of Counter Tubes in X-Ray Analysis

TLDR

End‑window Geiger, side‑window proportional, and NaI(Tl) scintillation counters are evaluated for their key properties in the 5–50 kVp X‑ray analysis region. The study compares these counters’ performance to identify the most suitable detector for X‑ray analysis. The authors describe an electronic discrimination method, explaining that measured intensity depends on the counter’s quantum‑counting efficiency and that peak‑to‑background ratio is set by the detector‑discriminator spectral response. Proportional and scintillation counters resolve in ~0.25 µs, eliminate Geiger nonlinearity, produce energy‑proportional pulses enabling simple pulse‑height discrimination for high peak‑to‑background ratios, and are as reliable and user‑friendly as Geiger counters.

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.