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Development of a triple GEM UV-photon detector operated in pure CF4 for the PHENIX experiment

2004; Elsevier BV; Volume: 523; Issue: 3 Linguagem: Inglês

10.1016/j.nima.2003.12.018

1872-9576

A. Kozlov, I. Ravinovich, L. Shekhtman, Z. Fraenkel, M. Inuzuka, I. Tserruya,

Dark Matter and Cosmic Phenomena

Results obtained with a triple Gas Electron Multiplier (GEM) detector operated in pure CF4 with and without a reflective CsI photocathode are presented. The detector operates in a stable mode at gains up to 104. A deviation from exponential growth starts to develop when the total charge exceeds ∼4×106 e leading to gain saturation when the total charge is ∼2×107 e and making the structure relatively robust against discharges. No aging effects are observed in the GEM foils after a total accumulated charge of ∼10mC/cm2 at the anode. The ion back-flow current to the reflective photocathode is comparable to the electron current to the anode. However, no significant degradation of the CsI photocathode is observed for a total ion back-flow charge of ∼7mC/cm2.