The effect of temperature on the counting rate-voltage characteristics of self-quenching Geiger-Müller counters with internal and external cathodes (in this paper denoted as counters Nos. 1 and 2) has been investigated within the temperatures ranging from 8° to 60° C.
It is found that the average counting rate remains independent of temperature (within the statistical error limits), and this constancy is better in the case of the external cathode counter than with the other. As counter No 1 shows a greater increase in slope at higher temperatures, the rate appears to be greater at higher applied potentials. Further, it is noticed that the plateau decreases and disappears at lower temperatures in the case of counter No 1, while counter No 2 does not show this effect. This is partly explained by the formation of semiconducting paths between the central wire and the cathode, the discharges along which give rise to spurious counts in the case of counter No 1, and the absence of these in the case of counter No 2.
It is also observed that the slope of the plateau increases and the width decreases with rise of temperature in both cases, though the increase in slope is more marked with counter No 1 than with counter No 2. The increase in slope is probably due to the presence of a greater number of multiple discharges or spurious counts at higher-temperatures, an important point which is under study.
The investigation also brings about the advantage of the external cathode in the construction and design of G-M counters, especially when reliable observations are desired with a counter under widely changing temperature conditions.