High-pressure xenon GPSC/MSGC hybrid detector

Gas proportional scintillation counter/microstrip gas chamber (GPSC/MSGC) hybrid detectors are based on a xenon-GPSC instrumented with a CsI-coated microstrip plate photosensor placed directly within the xenon envelope as a substitute for the photomultiplier tube. This design avoids the constraints due to the use of a quartz scintillation window for GPSC-photosensor coupling, which absorbs a significant amount of scintillation and is a drawback for applications where large detection areas and high filling pressures are needed. In this paper, we investigate the performance of a high-pressure GPSC/MSGC hybrid detector operating at 1, 1.5, 2, 2.5, and 2.85 atm. Detector energy resolution, light gain, and photosensor gain are studied as a function of the gas pressure from 1 to 2.85 atm and for different X-ray energies in the range of 6 to 88 keV. Energy resolutions of 11%, 5.5%, 3.4%, and 3% where obtained for 5.9 keV, 22 keV, 60keV, and 88 keV. No degradation of the detector performance was observed with increasing pressure, from 1 atm up to 2.85 atm.