Plain and Beaded Wire Geiger Counters for X-Rays

Abstract

The calibrations of typical self-quenching plain and beaded wire Geiger counters are studied for measurements of x-ray relative intensities over a range of 1 to 105 counts per second. For plain wire counters, correction for ``lost counts'' in terms of resolving time is found to be unreliable except at rates less than about 100 counts per second. The basic difficulty lies in a large and inconstant ratio of spurious to valid counts. This ratio depends upon counting rate, changes in counting rate, tube age, overvoltage, and spread of discharge. Beaded wire counters are studied as an improved type of counter for incident-ionizing events whose primary ionization does not extend along a large fraction of the length of the anode wire. For beaded wire counters, it is believed that corrections reliable to about 2 percent can be made to the observed counting rate over a rate range of about one to a thousand counts per second if the rate is not abruptly changed at rates above about 100 counts per second.