Speaker
Description
Summary
The ATLAS Pixel Detector [1] was connected to the electrical and cooling services and off-detector readout electronics in March 2008. All connections were certified before the detector was closed. Prior to the operation with the Large Hadron Collider (LHC) beam, all the necessary tuning procedures for the pixel detector have been performed, and the detector itself has been fully qualified. The detector has been successfully integrated into ATLAS Trigger and DAQ system, allowing for high efficiency in data recording, synchronously with other sub-detectors.
The detector functionality checks have been performed starting from the early production phase. For this purpose, dedicated calibration techniques have been implemented [2]. These techniques have been developed in each detector assembly stage, matching the demands for the real detector services and for the readout system. Additional calibration procedure, related to the operation within ATLAS, have been introduced. The characterization aims for stable operation of the detector and provides input for the offline analysis to guarantee high quality of the reconstructed data. Important detector characterization issues are:
- tuning of optical links - to have reliable connections between the detector and readout electronics and to adjust fine detector timing;
- threshold tuning - to have a uniform predefined threshold for all detector channels;
- ToT 1 tuning - to have a uniform detector response upon detection of the same deposited charge for all detector channels ;
- bump connectivity check - to check for unconnected channels;
- ToT calibration - to calibrate detector response to the input charge;
- noise occupancy check - to verify low-noise performance and spot noisy channels;
- timewalk check - to study timing behavior of detector channels;
- sensor check - to study charge collection efficiency and detector leakage current.
Previous experience with detector characterization so far has been limited to parts of the detector. For combined operation with test beam, only a few modules were used, whereas just one whole endcap (10% of the detector) was tested as a stand-alone setup under real operating conditions with cosmic muons [3]. In contrast, the results shown in this presentation give a summary of qualification tests for the whole detector in situ.
In addition to the above, the analysis of special data-taking runs with pseudo-random triggers to verify noise occupancy, as well as the outcome of combined runs with cosmic muons will be presented.
References
[1] G. Aad et al., ATLAS Pixel Detector Electronics and Sensors, to be published in Journal of Instrumentation, 2008
[2] ATLAS Pixel Collaboration, ATLAS Pixel Module Electrical Test Description, ATL-IP-QP-0144, 2004
[3] ATLAS Pixel Collaboration, Pixel Offline Analysis of Endcap A Cosmic Data, ATL-INDET-PUB-2008-003
