A single scatter electron Monte Carlo approach for simulating gamma-ray stopping efficiencies of Geiger-Müller counters

Simulation of gas filling in GM tube based on Garfield++ software

“…Then, the established model was imported into Garfield++ software, and the electrostatic field characteristics of tube, such as electric field, potential information and grid node information, were read out in the software. After introducing the working gas, the electron drift line without considering collision and avalanche and the electron avalanche process without considering collision and avalanche were simulated, and the dead time and signal amplitude of the charge signal output by the simulated GM tube were calculated [6,7].…”

“…If the average ionization energy of Ar is less than that of Ne, adding Ar into the working gas can enhance electron avalanche and thus increase the output signal, but the proportion of filling gas is the process secret of the manufacturer and has not been reported publicly. Therefore, it is very important to study the filling gas ratio and the real-time change of halogen gas ratio for the performance optimization of GM tube [6,7].…”

Enhancement of the intrinsic gamma-ray stopping efficiency of Geiger–Müller counters

“…In addition, it was thought that the fact that general purpose MC codes treat electron transport in an approximate manner [12] could have played a minor role in the underestimation of the intrinsic stopping efficiencies of the ZP1200. This observation was justified through the development of a specific purpose MC code, so-called GMMC (Geiger-Müller Monte Carlo) that employs detailed/microscopic electron transport in the pertinent problem geometry [13]. The specific purpose MC code GMMC was rigorously validated against experiments and MC simulations at photon energy of 59.5 keV.…”

“…The range rejection technique is, as mentioned in [13], implemented through a separate subroutine in the MC code GMMC. This technique applies only to electron transport as range is not a well-defined parameter in the case of photons.…”

“…it was assumed that every secondary electron penetrating into the fill gas would lead to a full Geiger discharge. Thus, simulation of electron transport in the fill gas was not considered [3,13]. This is a valid approximation that greatly simplifies the MC modeling of a bare GM counter.…”