Analytical calculation of the charge spectrum generated by ionizing particles in Resistive Plate Chambers at low gas gain

TL;DR

This paper analytically demonstrates that the charge spectrum in Resistive Plate Chambers at low gas gain follows a gamma distribution, aligning with simulation data and potentially explaining experimental observations.

Contribution

It provides an analytical derivation showing the charge spectrum follows a gamma distribution under specific conditions, extending understanding of RPC charge behavior.

Findings

Charge spectrum follows a gamma distribution at low gas gain.

Analytical results agree with simulation data.

Potential explanation for experimental data beyond initial assumptions.

Abstract

In this article it is shown analytically that the charge spectrum generated by ionizing particles in Resistive Plate Chambers under Townsend avalanche conditions, that is, for sufficiently small avalanches not affected by space-charge and considering single-electron ionization clusters follows closely the statistical gamma distribution. This distribution describes well comparable simulation data taken from the literature, but seems to describe as well experimental data measured beyond these assumptions, rising some interpretation issues.