Design Study and Optimization of Irradiation Facilities for Detector and Accelerator Equipment Testing in the SPS North Area at CERN

Due to increasing performance of LHC during the last years, the strong need of new detector and electronic equipment test areas at CERN appeared from user communities. This thesis reports on two test facilities: GIF++ and H4IRRAD. GIF++, an upgrade of GIF facility, is a combined high-intensity gamma and particle beam irradiation facility for testing detectors for LHC. It combines a high-rate 137Cs source, providing photons with energy of 662 keV, together with the high-energy secondary particle beam from SPS. H4IRRAD is a new mixed-field irradiation area, designed for testing LHC electronic equipment for radiation damage effects. In particular, large volume assemblies such as full electronic racks of high current power converters can be tested. The area uses alternatively an attenuated primary 400 GeV/c proton beam from SPS, or a secondary, mainly proton, beam of 280 GeV/c directed towards a copper target. Different shielding layers are used to reproduce a radiation field similar to the LHC “tunnel” and “shielded” areas in test zones around the target. In the first part of the thesis, the motivation for creating these two facilities along with an outline of the radiation damage effects on detectors and electronics is presented. An overview of similar facilities follows. In the next sections a detailed specification of the two facilities is given with emphasis on the description of the FLUKA Monte Carlo design and optimization studies. The commissioning and operation of the H4IRRAD facility is described next together with benchmark comparison between FLUKA simulations and measurements with beam. As a last part, the Medipix/Timepix detector measurement in H4IRRAD and its comparison with the Monte Carlo prediction are presented.