Tertiary scintillation gas proportional scintillation counter (TS-GPSC): First experimental results

A new concept for a gas detector is presented: the Tertiary Scintillation Gas Proportional Scintillation Counter (TS-GPSC). In this detector the electric field induced secondary gas scintillation is first detected by a CsI-coated GEM-like structure where it releases photoelectrons which are transferred through the GEM holes, with no charge multiplication, to another region where further field induced scintillation (tertiary) is produced and then again detected on a planar CsI-coated photocathode at the backplane of the detector. The electrons therein released are collected at a grid and constitute the detector´s signal. Since there is no avalanche charge multiplication in the detector, the gain will be quite stable and, moreover, as the field induced scintillation yield is very high, and in spite of the low photocathode quantum efficiency, the gain will be high and with low fluctuations, so an improvement in the energy resolution is expected. The first prototype of the tertiary scintillation detector was tested in a xenon atmosphere for hard X-rays and experimental results are presented.