Ourania Sidiropoulou (Bayerische Julius Max. Universitaet Wuerzburg (DE))
Radiation studies on several resistive bulk-micromegas chambers produced at the CERN will be overviewed in this presentation. These resistive bulk-micromegas chambers have been installed at the new CERN Gamma Irradiation Facility (GIF++) exposed to an intense gamma irradiation with the aim of carrying out a long-term ageing study in order to evaluate the detector behaviour under high irradiation. The chambers under study have an active area of 10 x 10 cm2, strip pitch of 400 μm, amplification gap of 128 μm, and the possibility to adjust the width of the drift gap as needed. The results on the detector performance as function of the photon rate up to 130 MHz/cm2 will be shown as well as the ageing properties as function of the integrated charge and the current intensity and its stability with time. In addition, the results of the efficiency measurements before, during and after the irradiation will be also presented as a function of the amplification voltage as which the chambers are operated. Finally, the experimental results will be compared with GEANT simulations in particular for the determination of the detector sensitivity to photons from 137Cesium.
Barbara Alvarez Gonzalez (CERN) Edoardo Maria Farina (Universita e INFN, Pavia (IT)) Fabian Kuger (Bayerische Julius Max. Universitaet Wuerzburg (DE)) Joerg Wotschack (Aristotle Univ. of Thessaloniki (GR)) Ourania Sidiropoulou (Bayerische Julius Max. Universitaet Wuerzburg (DE)) Paolo Iengo (CERN)