Characterizations of Cathode pad chamber as tracking detector for MUON Spectrometer of ALICE

The present thesis gives an overview of A Large Ion Collider Experiment (ALICE) at the Large Hadron Collider at CERN with particular emphasis on the contribution of the Indian Collaboration to the Muon Spectrometer. The two major activities of the Indian Collaboration namely, the 2$^{nd}$ Tracking Station and MANAS chip, have been covered in detail. A full scale prototype chamber (0$^{th}$ chamber) for the 2$^{nd}$ station was tested at CERN with beams from PS and SPS. Detail analysis of his data was carried out by me to validate the design and fabrication procedure for these large area Cathode Pad Chambers. This analysis also determined the production specifications of the MANAS chip. The thesis present every step which led to timely production of the ten chambers (two spare) of the 2$^{nd}$ station. At every stage strict quality control measures were adopted and various tests were carried out to validate every production step. I have been closely associated with the chamber production and all the validation tests. There are 28352 readout pads for every quadrant of the 2$^{nd}$ station. The readout scheme for these pads was implemented on an Electronic Exit board. I have been actively involved in this design which has been described in detail in Chapter 4. I have also participated in the quality control tests of all these PCBs and in the rectification of the production faults. The various validation tests for the quadrants were carried out at CERN after the air transport during November 2006 to April 2007. In this period, it was decided to install a strip support for the anode wires which was a major modification of the design and essential for the high voltage validation. This critical process was carried out successfully and has been described in Chapter 3 alongwith the validation test results. I was involved in every stage of this work. The 2$^{nd}$ station was successfully installed at the experimental site during May-July, 2007 and the final validation was completed in February 2008 by a team where I was a member. The satisfactory performance of the 2$^{nd}$ station was demonstrated in the Cosmic Muon Run in March, 2008 where I was one of the shifter. The Muon tracks through the Spectrometer was first observed during this run and the results have been reported in Chapter 6. The Indian collaboration also had a major responsibility in the design and fabrication of the Front End readout chip for all the 1,076,224 readout channels of the Muon Tracker. This readout electronics has been implemented on a 16 channel mixed signal VLSI chip named MANAS. A large number of validation tests were carried out on the first and the second production batches during April to August, 2005 to ensure satisfactory performance of MANAS. I have been closely associated to all these tests and all the results are reported in Chapter 4. The full scale production was lunched in October, 2005 and the delivery of 1,08,000 tested MANAS chips was completed in January, 2007. During my thesis work, I have successfully implemented the detail chamber geometry and pad mapping in the ALICE simulation framework, AliRoot. The incorporation of the detail detector geometry in AliRoot was essential for a realistic simulation of the Muon Tracks through the Spectrometer while the mapping is essential to decode the raw data. This work has been reported in Chapter 7. The final readout validation tests for Stations 3, 4 and 5 are currently underway and the Muon Spectrometer of ALICE will start data taking from the summer of 2009 where the first p-p collisions are expected. The measurement of p-p heavy flavour cross sections will be crucial to characterise the cold matter effects at LHC energies. This will be essential to quantify the differences between QGP and non-QGP effects. In future, the properties of the dense matter produced in A+A collisions will be investigated by studying its effect on the heavy quarkonium production cross section which will be measured by the Muon Spectrometer of ALICE.