Investigation of GaAs structures for microstrip detectors

Sammanfattning: The performance of Gallium Arsenide p-i-n detectors afterneutron irradiation has been studied. The detectors have beenirradiated with » 6 MeV neutrons at various neutronfluences up to approximately 6 ¢ 1014 n/cm2, protons andmixed beam up to 1015 p/cm2. Results are presented for thee®ect on leakage currents and charge collectione±ciencies for alpha particles irradiation and minimumionizing electrons. The signal from minimum ionizing electronswas well separated from the noise even at the highest neutronexposures achieved, therefore the diodes are still operationalas detectors. Saturation of damage is observed in both the I-Vcharacteristics and charge collection measurements. Theoperation of detectors at the LHC is most challenging in termsof radiation damage. Detectors for tracking applications insidethe inner cavity of an electromagnetic calorimeter and close tothe interaction point will receive charged particle doses inthe range of 11 Mrad and fast neutron fluences 1014 n/cm2during the lifetime of an experiment. Gallium Arsenidedetectors have been shown to be radiation resistant to neutronirradiation for fluences up to 1015 n/cm2 and consequently theuse of GaAs detectors as a part of the inner tracker has beenproposed by the ATLAS collaboration. For this work detectorswere irradiated in the Protvino I-100 Injector, U-70Accelerator and Neutrino decay channel at CERN. Allexperimental measurements was done within the RD8collaboration.