Advances in thick GEM-like gaseous electron multipliers Part II: Low-pressure operation

We present results on THGEM operation at low gas pressures, in the range 0.5–50 Torr. Gaseous gain up to 105 was recorded at 10 Torr of Isobutane in a single multiplier element, with pulses rise-time in the few ns range. Cascaded operation of two THGEMs is reported, with similar total gain but at lower voltages on each element. The present work encompasses a large variety of THGEM geometries and includes electric-field distribution calculations and electron transport simulations. We discuss the operation mechanism and some possible applications of THGEMs at low gas pressures.