Silicon pixel sensors developed by the ATLAS collaboration to meet LHC requirements and to withstand hadronic irradiation to fluences of up to 1015 neq/cm2 have been evaluated using a test beam facility at CERN providing a magnetic field. The Lorentz angle was measured and found to alter from 9.0° before irradiation, when the detectors operated at 150 V bias at B = 1.48 T, to 3.1° after irradiation and operating at 600 V bias at 1.01 T. In addition to the effect due to magnetic field variation, this change is explained by the variation of the electric field inside the detectors arising from the different bias conditions. The depletion depths of irradiated sensors at various bias voltages were also measured. At 600 V bias 280 μm thick sensors depleted to ≈200 μm after irradiation at the design fluence of 1 × 1015 1 MeV neq/cm2 and were almost fully depleted at a fluence of 0.5 × 1015 1 MeV neq/cm2. The spatial resolution was measured for angles of incidence between 0° and 30°. The optimal value was found to be better than 5.3 μm before irradiation and 7.4 μm after irradiation. © 2002 Elsevier Science B.V. All rights reserved

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We have successfully built and characterised a small animal PET based on 4 rotating detectors with a spatial resolution < 2 mm over its field of view and a sensitivity of 640 cps/mu Ci at the centre. The scanner is based on four matrices of 400 YAP:Ce finger crystals (2x2x30 mm(3) each) coupled to Position Sensitive PhotoMultipliers (Hamamatsu R2486-06.) We have now applied two high resolution collimators to two opposite detectors, hence realising an integrated PET-SPECT scanner for small animals. The collimators are made of lead with 20 mm long, 0.6 mm hexagonal holes with 0.15mm septa. The read-out and data acquisition system are handled by NIM-CAMAC standard electronics. The Field Of View (FOV) of the tomograph has a diameter of 4 cm and an axial length of 4 cm in both PET and SPECT configuration which is appropriate for mice and rat studies