VUV EMISSIONS IN GASEOUS DETECTORS

Following our previous works, we describe the time evolution of VUV ph otons emitted in Ar/CH4 and Ar/CO2 mixtures, during the development of electron avalanches occurring in cylindrical coaxial radiation detect ors. Particular attention is payed to emissions considered as relevant to the photon feedback mechanisms, namely the C I atomic lines at 156 .1, 165.7 and 193.1 nm. A correlation is obtained between the time spe ctra and the corresponding mean anode current signals, both for the pr oportional and the self-quenching streamer modes of operation. A compa rison is also made between the data obtained with two detectors having different cathode diameters (16 and 30 mm).