https://doi.org/10.1351/goldbook.P04885
A to . Each electron produced by the initial photo-
gas-filled X-ray detector
in which the electric potential
is high enough for the gain to reach a value in the range from ionization
causes one avalanche. Since the number of avalanche events is proportional to the energy of the incident photons, the charge collected by the anode
is proportional to the X-ray photon energy.