| High energy heavy ion collision is an important tool to research new phases of nuclei matter recently. The study of the interaction and performance of nuclei matter under extreme high temperature and high density by colliding two relativistic heavy nuclei is of great importance. It helps human to understand the formation and evolution of the universe. The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Lab (BNL) is one of the accelerators with the highest collision energy in the world. Its aim is to search Quark Gluon Plasma (QGP), study its characteristic and find the critical point of phase transition. STAR experiment is one of the four collaboration experiments at RHIC. Multi-gap Resistive Plate Chambers (MRPCs) were selected to construct the barrel Time of Flight (TOF) detector for the STAR experiments. MRPC is a gaseous detector with high detection efficiency and excellent time resolution. It is a good choice for particle identification (PID) in high multiplicity final states in Heavy Ion Collision. This detector will significantly extend the reach of the STAR scientific program, and greatly enhance the identification capability of charged hadrons to more than 95% of all those produced within the MRPC-TOF acceptance (η<1). The increase in particle identification efficiency over a large solid angle will enhance the PID physics abilities, which is important to search for Quark Gluon Plasma. The extended momentum range for particle identified spectra provided by the MRPC barrel TOF detector is crucial to understand the information contained in the large scale correlations and fluctuations observed in Au+Au collisions at RHIC.Chapter 3 particularize large amount of jobs which have been done by the High Energy Physics Group of USTC during China-US cooperation—the MRPC mass production, includes the research and development of MRPC since 2000, the building of the cleaning room for MRPC assembly, the market research and quality assurance of materials of MRPC, the standardization of the production flow, the establishment of criterion, the manufacture craft, the dark current measurement of electrode, the quality control of mechanical dimensions of modules, the flow arrangement of cosmic ray test and the development of the MRPC database website. Thanks to all these contributions, the High Energy Physics Group of USTC accomplishes the production and measurement task ahead of half a year, and the excellent performance of MRPC modules has received a lot of praise from the US. Chapter 4 introduces the framework and function of database, the structure of the network station, the usage of the website, and what the role has been played in the quality control of MRPC mass production. The development of MRPC database website is one of main contribution to the quality assurance and quality control of MRPC mass production. It has expected positive effect on the conservation of the MRPC mass production and test results of MRPC modules, and the members of the Cooperation Group can grasp the information of MRPC modules in time.Chapter 5 presents research and discussion of the performance parameters of MRPC modules based on the MRPC database. To make sure the results are correct and reliable, some reasonable improvements are made based on the previous code and some effects of unstable factors have been precluded. Some conclusions are obtained: the peak of ADC spectrum is given by landau fitting, which is linear correlated with stretching of ADC spectrum. The relations between the performance parameters are studied. The ratio of avalanche signals is related to the time resolution. Time resolution performance is better with large avalanche signal ratios. A lot of statistic works are also made based on the new analysis results. With these studies, the working mechanisms of MRPC are better understood. |
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