Speaker
Andre Lukas Schorlemmer
(CERN / Georg-August-Universitaet Goettingen (DE))
Description
With the rapidly increasing LHC luminosity, radiation damage effects in the ATLAS Pixel Detector will become critical to the detector operation and performance. Thus, it is necessary to monitor the impact of the irradiation on a regular basis. One crucial observable is the voltage that is needed to fully deplete the pixel sensor. Before type-inversion this is monitored in the Pixel Detector during routine maintenance stops of the LHC by a scan that exploits the cross-talk between neighbouring pixels. A high-ohmic short between pixels exists as long as the sensor is not fully depleted. If the sensor is fully depleted, then the pixels are isolated from each other. The cross-talk scan reads-out a pixel while charge is injected into two adjacent pixels. The change in cross-talk is measured while increasing the bias voltage. Radiation damage effects cause a decrease of the n-type doping concentration in the sensor bulk. Thus, the effective depletion voltage reduces with time, while annealing effects can induce a rise of the effective depletion voltage. The evolution of the effective depletion voltage during the last year is reported in this talk.
Author
Andre Lukas Schorlemmer
(CERN / Georg-August-Universitaet Goettingen (DE))
