Bonn 2020 – scientific programme

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T: Fachverband Teilchenphysik

T 110: Combined instrumentation session IV: Semiconductor detectors (joint session HK/T)

T 110.7: Talk

Friday, April 3, 2020, 12:30–12:45, H-HS XV

A precision floating, high-voltage picoamperemeter — •Florian Rössing, Tobias Rudolph, Dimitri Schaab, and Bernhard Ketzer — Universität Bonn, Helmholtz-Institut für Strahlen- und Kernphysik, Bonn, Germany

Many modern tracking detectors, e.g. the Time Projection Chambers for ALICE and CBELSA, are based on Micropattern Gaseous Detector (MPGD) technology. In the examples given above, Gas Electron Multipliers (GEM) will be used for the amplification of primary charges. The optimization of MPGD often requires current measurements at the level of picoamperes on the high-voltage lines. Therefore, current-meters with a complete electrical insulation from ground are needed, requiring wireless data transmission and floating power supply. Previous versions of devices custom-made at TU München and further developed at Bonn University showed problems with the overvoltage-protection, a residual non-linearity and a non-negligible temperature dependence. In order to overcome these issues the analog signal processing was completely revised. The shunt resistor configuration in use was replaced by a zero burden transimpedance amplifier, with high input impedance. A precise temperature sensor and a photovoltaic powering were added. In the talk design characteristics and the performance of the devices will be discussed.