Bonn 2020 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 63: Combined Instrumentation Session: Semiconductor Detectors (joint session HK/T)

HK 63.4: Talk

Friday, April 3, 2020, 11:45–12:00, H-HS XV

Study of thermal runaway of hadron-irradiated silicon sensors — Ingo Bloch¹, Heiko Lacker², •Felix Riemer², and Christian Scharf² — ¹Deutsches Elektronen-Synchrotron DESY — ²Humboldt-Universität zu Berlin

Silicon sensors are widely used in the several parts of the ATLAS detector at the LHC. Low leakage current is desirable since the leakage current generates heat. At the same time the leakage current increases with increasing sensor temperature. Thermal runaway will occur if the heat removed from the sensor is lower than the heat generated by the sensor. During operation the silicon sensors at hadron colliders are exposed to high fluences of highly energetic particles which introduce defects in the crystal lattice strongly increasing the leakage current. The cooling infrastructure of the detector has to be adapted order to prevent thermal runaway during operation until the end-of-life. Therefore, the capacitance and current of irradiated silicon diodes have been measured as a function of the particle fluence, temperature, bias voltage, heating power, and for different pad areas. The diodes were irradiated with 70 MeV/c protons and 1 MeV/c neutrons to equivalent fluences between 1· 10¹³ cm⁻² and 5· 10¹⁶ cm⁻². The goal of the study is to develop models for the capacity and reverse current of highly irradiated silicon sensors which can be used to estimate the cooling power needed to prevent thermal runaway while fully depleting the sensors after high particle fluences.