The calibration of the resistive plate chambers of ATLAS

Resistive Plate Chambers (RPC) are used in ATLAS to provide the first level muon trigger in the barrel region. The total size of the system is about 16000 m(2), read out by about 350000 electronic channels. To reach the needed trigger performance, a precise knowledge of the detector working point (from the point of view of both high and low voltage settings) is necessary and the high number of readout channels calls for severe requirements on the analysis tools. First of all, high-statistics data samples will have to be used as input. Second, the results would me unmanageable without a proper interface to some database technology. Moreover, the CPU power needed for the analysis makes it necessary to used is tributed computing resources. A set of analysis tools will be presented, coping with all the critical aspects of this task, ranging from the use of a dedicated data stream (the so-called muon calibration stream), to the automatic job submission on the GRID, to the implementation of an interface to the conditions database of ATLAS. The integration with Detector Control System information and the impact of the calibration on the performance of there construction algorithms will be discussed as well.