Gaseous Photomultiplier Research Articles

The scintillation of CF 4 and its relevance to detection science

The scintillation properties of CF 4 are presented in comparison with those of Xe and CH 4. Alpha-particle induced photon emission was measured with vacuum phototubes and with a CsI-based gaseous photomultiplier. The latter method provides an absolute sensitivity of such devices to particle-induced UV-photon background in CF4 and CH4 gaseous Cherenkov radiators. Integrated CF 4 scintillation yields over the range of 150–220 nm are, on the average, 315±95 to 242±60 photons/MeV, in the respective pressure range of 0.063 to 0.75 atm, compared to CH 4 which emits 0.06±0.01 photons/MeV at 1 atm. The total photon yield, integrated over the full emission spectrum of CF 4 (150–500 nm), is of the order of 1200 photons/MeV × 4 π. The primary scintillation photon yield of CF 4 is about 16(±5)% of that of Xe. No proportional secondary scintillation was observed in CF 4. The avalanche-induced photon yield was measured to be of the order of 0.3 photons per electron. The implications of this considerable photon emission, are discussed.