Novel geometries to reduce the spectroscopic degradation associated with the drift-field of radiation detectors: a Monte Carlo simulation study for xenon-filled counters

Many radiation detectors make use of an electric field to drift the electrons that result from the absorption of the incoming radiation. Previous simulation studies have demonstrated that, in gas detectors, the fact that charged particles exchange energy with the field leads to a degradation of the system's spectroscopic capabilities. New geometries based on opposite electric fields may reduce this effect, as somehow, a compensation of the energy that is gained/lost from/to the field is achieved. In this communication, the performance of several xenon-based radiation detectors with these novel geometries was assessed using the Monte Carlo code PENELOPE. At energies of 100 and 200 keV, and considering 1, 2, 4 and 8 regions with opposite electric fields, the simulation results indicate that the degradation associated with the drift electric field can be reduced and that this achievement is more noticeable for higher photon energies. In what concerns the absorption of 200 keV photons, when considering a detector with 8 regions, rather than one with a standard geometry, it has been observed a decrease of 81% in the FWHM of the gaussian curve describing the peak that corresponds to full energy absorption events.