Noble-gas operation of Micro-Hole and Strip Plate electron multipliers at atmospheric-to-high pressures

We present the performance of a Micro-Hole and Strip Plate (MHSP) electron multiplier in argon–xenon mixtures, at pressures of 1–7 bar. This microstructure can operate at high pressures without significant reduction of the maximum achievable gain. Absolute gains of 1–4×103 were reached in Ar/50 mbar Xe over this pressure range; the maximum gain is imposed by the discharge limit, dropping at higher pressures. Energy resolutions between 14% and 16% were reached for 6 keV X-rays; they do not degrade significantly with increasing pressure. Better performances are expected by improved manufacturing of the MHSP.