RESEARCH AND DEVELOPMENT ON RESISTIVE PLATE CHAMBER BASED MUON TOMOGRAPHY SYSTEM

Abstract

Cosmic ray muons are the particles which are continuously falling on earth’s surface. It is observed that while travelling through materials having high atomic number , muons undergo the phenomenon called multiple Coulomb scattering. Using this property and detecting the unscattered and scattered muons their tracks can be reconstructed to get a image of the material through which muons have passed. It is possible by using particle detectors like Gas electron multiplier (GEM) ,drift tubes etc. In this dissertation , I have reported the process of fabrication of six resistive plate chambers (RPC) for this purpose. Six resistive plate chambers were fabricated using high resistive bakelite plates . These gaseous detectors were thoroughly tested to determine whether they are suitable or not for the purpose of muon tomography. The characterization reports, which have shown very successful results are given in details . It includes surface resistance measurement, I-V characterization, current stability test , efficiency measurement and calculation of noise rate in different voltages. A proper simulation study of the resistive plate chamber dynamics was also carried out by using the simulation toolkit GARFIELD++ , the study report is presented in chapter 3. The calculation of electrostatic field , generation of ionization in avalanche mode of RPC was done along with calculation of signal generation with the simulation toolkit. After completion of fabrication of the detectors, suitable front end electronics was selected by testing them with RPCs. Among conventional electronics , PADI-application specific integrated circuit (ASIC) and NINO-ASIC front end electronics. Among these, NINO-ASIC have shown the best result . Further testing was done using NINOASIC based front end electronics. A six bakelite resistive plate chamber based muon tomography prototype system was constructed and preliminary data was collected using cosmic ray muons . A MUCH-XYTER ASIC based data acquisition system was used for this purpose.