Data Quality Monitoring of the CMS Tracker

The Data Quality Monitoring system for the Tracker has been developed within the CMS Software framework. It has been designed to be used during online data taking as well as during offline reconstruction. The main goal of the online system is to monitor detector performance and identify problems very efficiently during data collection so that proper actions can be taken to fix it. On the other hand any issue with data reconstruction or calibration can be detected during offline processing using the same tool. The monitoring is performed using histograms which are filled with information from raw and reconstructed data computed at the level of individual detectors. Furthermore, statistical tests are performed on these histograms to check the quality and flags are generated automatically. Results are visualized with web based graphical user interfaces. Final data certification is done combining these automatic flags and manual inspection. The Tracker DQM system has been successfully used during cosmic data taking and it has been optimised to fulfill the condition of collision data taking. In this paper we describe the functionalities of the CMS Tracker DQM system and the experience acquired during proton-proton collision.