Suren Kandasamy Dissertation.pdf - University of Surrey

Peak efficiency (%)(%)M.Sc DissertationTable 4.6 Measured photopeak efficiency for LaCl 3 :Ce detector at various – rayenergiesPhoto peakefficiencySourceEnergy(keV)Activity(Bq)I( E )NN PhotopeakC P(cps)%152 Eu 121.78 152911 0.28 42815.08 2336.94 525 22.46 0.03152 Eu 244.70 152911 0.07 10703.77 584.24 84 14.38 0.07152 Eu 344.27 152911 0.27 41285.97 2253.48 247 10.94 0.0422 Na 511.00 20045 1.80 36081.00 1969.38 73 3.72 0.02137 Cs 662.00 259845 0.85 220868.25 12055.47 1378 11.43 0.01152 Eu 778.96 152911 0.13 19878.43 1085.01 123 11.38 0.05152 Eu 964.00 152911 0.15 22936.65 1251.93 86 6.90 0.04152 Eu 1112.05 152911 0.13 19878.43 1085.01 84 7.76 0.0360 Co 1173.24 39928 1.00 39927.80 2179.35 134 6.17 0.0322 Na 1274.50 20045 1.00 20045.00 1094.10 13 1.17 0.0260 Co 1332.50 39928 1.00 39927.80 2179.35 119 5.48 0.02152 Eu 1407.92 152911 0.21 32111.31 1752.71 59 3.36 0.02pError±%The full energy photopeak efficiency expresses the ability of the detector tomeasure photons at specific energies. From Fig 4.8 it was found that, as expected, itdecreases with the energy of the photons at specific energies. This result was expectedas the cross section of the photoelectric effect decrease with the energy of photons.30.0025.0020.0015.0010.005.000.00100.00 300.00 500.00 700.00 900.00 1100.00 1300.00 1500.00Photo peak energy (keV)Figure 4.8 Photopeak efficiencies as a function of peak energy.K. Suren 27