Interpretation of effective gain variations with the drift electric field for a ceramic thick gas electron multiplier

The effective gain variations as a function of the drift electric field strength (E-d) are measured in a ceramic thick gas electron multiplier (THGEM) and a standard GEM using the same experimental setup. Significant differences in the variations are observed between the THGEM and the standard GEM. The effective gain variations with E-d are quantitatively reproduced by calculations via investigating the respective influence of E-d change on the electron collection efficiency and the gain. The differences in the effective gain variation with E-d between the THGEM and standard GEM are thus explained.