Understanding Neutron Radiography Post Exam Reading VIII-Part 2a of 2A

PART 3. Geiger-Müller Counters
Operating Voltage Level
Increasing voltage beyond the proportional region (Fig. 3) will eventually
cause the gas avalanche to extend along the entire length of the anode wire.
When this happens, the end of the proportionalregion is reached and the
geiger-müller region begins. An instrument operating in this voltage range,
using a sealed gas filled detector, is referred to as a geiger-müller counter, a
GM counter or simply a geiger tube. This instrument was introduced in 1928
and its simplicity and low cost have made it the most popular radiation
detector since then. Geiger-müller counters complement the ion chamber and
proportional counter and comprise the third category of gas filled
detectors based on ionization.
Charlie Chong/ Fion Zhang