Freya Blekman

Shown: A CMS endcap pixel half-ring. There are two out of twelve blades equipped with active detectors, the other locations are occupied with dummy panels.

The CMS pixel detector is situated in the center of the experiment, it is the first layer of the apparatus after collision. As all tracking in CMS, it is based on analogue tracking technology, which enables us to also measure the energy deposited by the particle when traversing the detector layers. The pixel consists of about 66 million pixels, and is divided in a central (barrel, 48 million pixels) and two forward (endcap, 18 million pixels) detectors.

In the forward pixel detector the individual pixels are 100x150 microns. The pixels are bump-bonded to readout chips, each chip is used to read out 4160 (80x52) channels.

Vital statistics

A list of numbers.

• Number of channels
• Number of detector units (plaquettes)
• Number of ROCs
• Number of FEDs

Detector Calibration

On the calibration of the detector.

Gain Calibration

The gain calibration is used to parameterize the response of the pixel detector, which is particularly important for the case when only little energy is deposited in each pixel.

Pixel detector software in CMSSW

Part of the calibrations and a significant part of the calibration analysis is done in CMSSW, the CMS software framework. I am responsible for the development of the following calibration packages

Gain Calibration.

This calibration will run on the trigger farm.

Pixel Alive calibration.

This calibration is mainly used for commissioning purposes in the Tracker Integration Facility (TIF).

S-Curve calibration.

This calibration, which probes the noise and threshold levels of single pixels, will be run mainly during commissioning at the TIF and detector installation.

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