Suren Kandasamy Dissertation.pdf - University of Surrey

M.Sc DissertationChapter 3Experimental Apparatus and MethodH.VSourceDetectorPMTShapingAmplifierMCADisplayFigure 3.1 The schematic diagram is used to get the energy spectrum from theLaCl 3 :Ce(10%) detector.3.1 To select the supply voltage of the LaCl 3 :Ce DetectorAs shown in the Fig. 3.1 the LaCl 3 :Ce(10%) with the size of 44.450.8mmBrilLanCe B350 scintillator detector directly coupled with Hamamatsu R6231photomultiplier tube (PMT). Then the PMT tube was connected with Canberra 3102Dpositive high voltage power supply and ORTEC 672 shaping amplifier. The amplifieroutput signal was connected to ORTEC (1024 channel) Multi-Channel Analyser (MCA)and the data analyzed with the ORTEC Maestro for windows software.After that the shaping time and coarse gain of the shaping amplifier were set tolow values, such as 0.5 s and 20 respectively. Then the 137 Cs source was placed infront of the detector and the distance between source and detector was kept around 4cm. The voltage of the high voltage power supply was increased slowly from 0 Voltuntil get the signal in MCA. Then the corresponding voltage was noted down. After thatthis voltage was increased by 20 Volt and corresponding spectrum was collected in thecomputer. For each step the acquiring time was kept as 300 sec. Finally the totalnumber of net counts was noted down for each spectrum and then the graph of totalnumber of net counts versus supply voltage was plotted.K. Suren 13