Intensive irradiation studies, monitoring and commissioning data analysis on the ATLAS MDT chambers

The ATLAS MDT chambers have been extensively studied, starting from irradiation test to commissioning activities. First, a detailed description of high rate and high background tests is given. These tests have been carried out on a small ATLAS-like MDT chamber, by the Cosenza and Roma TRE groups. The precision tracking chambers of the muon spectrometer, in fact, have to operate for more than 10 years in the harsh LHC background, due mainly to low energy neutrons and photons. Aging effects, such as the deterioration of the tube themselves can appear and difficulties in pattern recognition and tracking may occur. Moreover an upgrade to Super-LHC is foreseen. Then, there is an accurate description of the MDTGnam package, the official software for the on-line monitoring of MDT performances. When dealing with a complex apparatus, such as the ATLAS experiment, an on-line monitoring system is a fundamental tool. The GNAM project, developed by Cosenza, Pavia, Pisa and Napoli groups, is a monitoring framework to be used by all the ATLAS detectors. The work described in this thesis consisted in writing and optimizing the GNAM C++ code for the MDT detector specific part. The last part is devoted to commissioning data analysis from barrel sector 13. Sector 13 was used as a pilot system to test different detector data taking in their final conditions. Up to November 2006, 13 MDT chambers were installed and their performance monitored both by means of usual noise tests and by cosmic rays penetrating the ATLAS cavern. In addition, the barrel toroid was switched on for the first time at the nominal current. Results from the magnet test are also reported.