Mainz 2014 – scientific programme
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T: Fachverband Teilchenphysik
T 88: Halbleiter 5
T 88.5: Talk
Wednesday, March 26, 2014, 17:45–18:00, P109a
X-Ray Calibration for the Phase 1 Upgrade of the CMS Pixel Detector — •Jennifer Sibille, Matteo Centis Vignali, Erika Garutti, Tobias Lapsien, Stefan Mättig, and Georg Steinbrück — Universität Hamburg
The instantaneous luminosity of the Large Hadron Collider (LHC) is being increased in several steps over the next 10 years to maximize its discovery potential for new physics. However, at a luminosity of twice the design luminosity of the LHC of 1 × 1034 cm−2 s−1, the performance of the current CMS pixel detector is degraded by substantial deadtime incurred by the readout chip (ROC). CMS will replace the current three-layer pixel detector in 2016/17 by a new four-layer detector. The new readout chip used in the barrel detector will have increased buffering capabilities to minimize deadtime, and digital readout protocol to increase the readout speed.
The readout chip has an internal calibration circuit that can inject charge into the preamplifier, simulating a signal. This calibration circuit is used to define many chip parameters, including the threshold, and so needs to be calibrated. This calibration is done using well-defined fluorescence x-rays. The results of this calibration on prototype modules before and after irradiation is presented.