Speaker
Description
Electroluminescence (EL) is the phenomenon of light emission, by a material, following electron impact in the presence of an external electric field. Gas Proportional Scintillation Counters (GPSC) use this effect in noble gases as an amplification process of the ionization signal induced by radiation interaction in the gas. Several geometries have been proposed and developed for this type of radiation detectors, the most common being the double grid assembly defining two different regions, the absorption and the electroluminescence region. One limitation in this type of detector is the ratio between the size of the detector radiation-window to the size of the photosensor reading out the EL. This restricts the large-window operation as the solid angle subtended by the photosensor relative to the electroluminescence region is dependent on the location of the radiation interaction in the gas medium. In this work, we propose the use of an annular electroluminescence region from which the solid angle of the EL production in respect to the photosensor is constant. This enables the use of a large radiation window area as the photon emission position is independent from the position of the primary interaction. Other advantages are inferred such as the simpleness of the detector design along with the low power electronics possibility, contributing both to a portable GPSC solution. We report on the latest results for the energy resolution capabilities for 5.9, 22.1 and 56 keV following the latest improvements in the electric system and in the light collection, reporting a GPSC with a radiation window area of 50 cm$^2$ and a photosensor sensitive area of 18 cm$^2$ for Xenon gas at 1.09 bar. Also reported are the results for large area capabilities for several ratios between the window size and photosensor active area, presenting an exceptional performance for six times the radiation window area, in respect to the photosensor sensitive, 2 cm$^2$ area, using an LAAPD. Several results are also presented from a comprehensive simulation study of the detector obtaining a good agreement between the simulated and experimental performance, the latter obtained using the x-rays interacting directly with the LAAPD to calculate the electroluminescence yield. This type of portable room-temperature detector, with large-detection-area and large-detection-volume, can compete with solid-state detectors in x-ray astronomy applications.
