The performance of the GPSC/MSGC hybrid detector with neon-xenon gas mixtures

The performance for x-ray spectrometry of neon-xenon gas proportional scintillation counters using a CsI-coated microstrip plate in direct contact with the scintillation gas as a VUV photosensor is investigated for different neon-xenon mixtures. At best operation conditions, the detector gain can reach values about 50% higher than those achieved with pure xenon filling. The highest gains and the best energy resolutions are achieved for xenon contents around 40%. However, the achieved energy resolutions are similar to those achieved with pure xenon. As in pure xenon and argon-xenon mixture gas-fillings, the detector performance is limited by optical positive feedback resulting from additional scintillation produced in the electron avalanche processes around the MSP-anodes. Best energy resolutions are achieved for positive feedback gains in the range of 1.1 to 1.2. The performance achieved with neon-xenon mixtures is inferior to that achieved with argon-xenon mixtures.