Suren Kandasamy Dissertation.pdf - University of Surrey

Resolution (%)M.Sc DissertationUsing the values shown in Table 4.4 the graph of energy resolution versus gammaray energy was plotted, as shown in Fig. 4.7.11.509.50Resolution% (FWHM)Resolution% (76.3/root(E))7.505.503.501.5050.00 250.00 450.00 650.00 850.00 1050.00 1250.00 1450.00Energy (keV)Figure 4.7 Energy resolutions as function of photon energyFigure 4.7 shows the energy resolution as function of photon energy between121.78 keV and 1407.92 keV. The energy resolution of 3.70 ± 0.15 % (FWHM) for 662keV gamma rays were calculated with the size of 44.450.8mmLaCl 3 :Ce(10%)scintillator detector coupled to an R6231 PMT at room temperature. Which is excellentfor scintillator based systems and it has been never achieved with established inorganicscintillator [11]. It should be noted the energy resolution obtained the size of 44.450.8mmLaCl 3 :Ce(10%) crystal approaches the energy resolution of roomtemperature semiconductor detectors such as CdTe and CdZnTe of similar size. Figure4.7 shows the energy resolution faithfully follows the statistical value of constant timesone over square root of energy [5]. That means the energy resolution of LaCl 3 :Ce(10%)is approximately inversely proportional to the square root of the energy [8].And also the energy resolution was characterized by LaCl 3 :Ce(10%) with the sizeof 44.450.8mmcrystal using other gamma ray energies such as 121.78 keV( 152 Eu), 511 keV ( 22 Na), and 1407.92 keV ( 152 Eu) and have found its energy resolutionto be 11.26 ± 0.82% (FWHM), 4.18 ± 0.20 % (FWHM) and 2.70 ± 0.07 % (FWHM),respectively, at room temperature. From the Fig. 4.7 it can be deduced that the energyresolution of LaCl 3 :Ce(10%) with the size of 44.450.8mmcrystal is poorer at lowK. Suren 25