Comparison of 35 and 50 μm thin HPK UFSD after neutron irradiation up to 6 • 10~(15) neq/cm~2

摘要

We report results from the testing of 35 mu m thick Ultra-Fast Silicon Detectors (UFSD) produced by Hamamatsu Photonics (HPK), Japan and the comparison of these new results to data reported in a previous paper on 50 mu m thick UFSD produced by HPK. The 35 mu m thick sensors were irradiated with neutrons to fluences of 1.10(14), 1.10(15), 3.10(15), 6.10(15) neq/cm(2). The sensors were tested pre-irradiation and post-irradiation with minimum ionizing particles (MIPs) from a Sr-90 beta-source. The leakage current, capacitance, internal gain and the timing resolution were measured as a function of bias voltage at -20 degrees C and -27 degrees C. The timing resolution was extracted from the time difference with a second calibrated UFSD in coincidence, using the constant fraction discrimination method for both devices. Within the fluence range measured, 35 mu m thick UFSD present advantages in timing accuracy, bias voltage and power consumption.