THE SCINTILLATION OF CF4 AND ITS RELEVANCE TO DETECTION SCIENCE

The scintillation properties of CF4 are presented in comparison with t hose of Xe and CH4. Alpha-particle induced photon emission was measure d with vacuum phototubes and with a CsI-based gaseous photomultiplier. The latter method provides an absolute sensitivity of such devices to particle-induced W-photon background in CF4 and CH4 gaseous Cherenkov radiators. Integrated CF4 scintillation yields over the range of 150- 220 nm are, on the average, 315+/-95 to 242+/-60 photons/MeV, in the r espective pressure range of 0.063 to 0.75 atm, compared to CH4 which e mits 0.06 +/- 0.01 photons/MeV at 1 atm. The total photon yield, integ rated over the full emission spectrum of CF4 (150-500 nm), is of the o rder of 1200 photons/MeV X 4 pi. The primary scintillation photon yiel d of CF4 is about 16(+/-5)% of that of Xe. No proportional secondary s cintillation was observed in CF4. The avalanche-induced photon yield w as measured to be of the order of 0.3 photons per electron. The implic ations of this considerable photon emission, are discussed.