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T: Fachverband Teilchenphysik
T 66: Halbleiterdetektoren: Strahlenhärte und neue Materialien
T 66.8: Talk
Thursday, March 1, 2012, 18:30–18:45, ZHG 001
Diamond Pixel Detectors in High Radiation Environments — •Jieh-Wen Tsung1, Mirek Havranek1, Fabian Hügging Hügging1, Harris Kagan2, Michael Karagounis1, Hans Krüger1, and Norbert Wermes1 — 1Physikalisches Institut, Nußallee 12, Bonn, Germany — 2Department of Physics, The Ohio State University, 191 W. Woodruff Ave., Columbus, Ohio, U.S.A
Diamond is attractive for sensors of vertex detectors because of its strong radiation-hardness. Its tiny leakage current and smaller capacitance result in low noise. However, silicon (Si) gives larger signals, while its noise level is similar to diamond before irradiation. This situation changes in high radiation environments, e.g. super Large Hadron Collider, at where a particle fluence 1016 neq/cm2 is expected. To compare the diamond and Si pixel detectors, their signal-to-noise ratio (SNR) versus irradiation is estimated. For the signals, the decreasing mean free path of charge carriers versus irradiation is measured using diamond pad detectors, and the results are applied to predict the signal deterioration. The noise is calculated based on a model of the pixel readout circuit, and also simulated using chip design software with the leakage current and input capacitance to the charge sensitive amplifier as key parameters. The input capacitance has never been clearly identified in pixel detectors, so a measuring chip (PixCap) has been developed to directly measure it. With all the mentioned ingredients, the SNR of diamond and silicon pixel detectors is estimated up to 1016/cm2 fluence. Finally, we present the measurements of diamond and Si pixel detectors with the ATLAS FE-I4 pixel readout chip.