A gas proportional scintillation counter with annular anode geometry aiming large detection areas for x- and gamma-ray spectroscopy

A gas proportional scintillation counter with an annular shape anode aligned with the photosensor axis has been proposed. In this design, the electroluminescence (EL) region is limited to a small region near the anode surface, severely constraining the variations of the solid angle subtended by the photosensor relative to the whole region. Therefore, the EL collected at the photosensor is independent from the radiation interaction position, allowing large detection areas when compared to those of the photosensor. However, the scintillation region is located further away from the photosensor when compared to other geometries, reducing significantly the EL collected at the photosensor, which can result in a degradation of the energy resolution of the detector. A dedicated firmware is described, aiming to perform detailed studies on the optimal anode-to-photosensor distance and anode-to photosensor diameter ratio that can be implemented without significant degradation of the detector energy resolution. A first prototype was assembled in order to obtain experimental results serving as benchmark, validating the developed simulation firmware. • A new concept for a GPSC is studied, featuring an annular anode. • This concept enables the use of large photosensor-to-radiation window size ratios. • A simulation framework was developed to study the GPSC performance. • The framework was validated by the experimental and simulation results agreement. • This framework will be used to define the optimal dimensions of the GPSC elements.