Operation of MHSP multipliers in high pressure noble-gas

F.D. Amaro; J. F. C. A. Veloso; A. Breskin; R. Chechik; J. M. F. dos Santos

F.D. Amaro Physics Dept., University of Coimbra
J. F. C. A. Veloso Physics Dept., University of Coimbra; Physics Dept., University of Aveiro
A. Breskin Dept. of Particle Physics, The Weizmann Institute of Science
R. Chechik Dept. of Particle Physics, The Weizmann Institute of Science
J. M. F. dos Santos Physics Dept., University of Coimbra

Resumo

We report on the performance of a Micro-Hole & Strip Plate (MHSP) electron multiplier operating in pure Xe, Kr, Ar and Ne at the pressure range of 1 to 6 bar and in Ar – Xe mixtures at pressures ranging from 1 to 7 bar. The maximal gains at 1 bar Xe and Kr are 5*104 and 105, respectively; they drop by about one order of magnitude at 2bar and by almost another order of magnitude at 5-6 bar; they reach gains of 500 and 4000 at 5 bar in Xe and Kr, respectively. In Ar, the gain varies very little with pressure, from 3*103 to 9*103; in Ne the maximum attainable gain, about 105, is pressure independent above 2 bar. The results are compared with that of single- and triple-GEM multipliers operated in similar conditions. Potential applications are in hard X-ray imaging and in cryogenic radiation detectors. In the Ar - Xe mixture no significant reduction of the maximum achievable gain was measured. Absolute gains of 1–4*103 were reached in Ar/50 mbar Xe over this pressure range from 1 to 7 bar. Energy resolutions between 14% and 16% were reached for 6 keV X-rays.