%0 Journal Article %T Development of a triple GEM UV-photon detector operated in pure CF4 for the PHENIX experiment %A A. Kozlov %A I. Ravinovich %A L. Shekhtman %A Z. Fraenkel %A M. Inuzuka %A I. Tserruya %J Physics %D 2003 %I arXiv %R 10.1016/j.nima.2003.12.018 %X Results obtained with a triple 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 10^4. A deviation from exponential growth starts to develop when the total charge exceeds ~ 4 10^6 e leading to gain saturation when the total charge is ~ 2 10^7 e and making the structure relatively robust against discharges. No aging effects are observed in the GEM foils after a total accumulated charge of ~ 10 mC/cm^2 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 ~ 7 mC/cm^2. %U http://arxiv.org/abs/physics/0309013v1