Development of gaseous PMT with micropattern gas detector

We have developed gaseous photomultiplier tubes (PMTs) with a bialkali photocathode, combined with micropattern gas detectors (MPGDs) such as a glass capillary plate (CP), a gas electron multiplier (GEM) and a Micromegas detector. Gaseous PMTs with two different gas mixtures of Ar (90%)+CH4 (10%) and Ne (90%)+CF4 (10%) were investigated at a gas pressure of 1 atm. Quantum efficiencies of up to 12% were obtained for both neon and argon gas mixtures. A new glass CP made of Pyrex glass has been developed for a hole-type MPGD. The glass is well-suited for high-level cleanliness and reaction conditions required for the production of bialkali photocathodes. A gain of up to 1.5×104 and an energy resolution of 23% were obtained for 5.9 keV X-rays. This latest result and the basic performance of the gaseous PMTs are described.