Suren Kandasamy Dissertation.pdf - University of Surrey

M.Sc DissertationAbsolute total efficiency ABSis defined as the ratio of the pulses recorded by thedetector to the number of radiation quanta emitted from the source. This thereforeincludes solid angle effects, iefrom the source.ABSdecreases as the detector is moved further awayAbsolute total efficiency, ABS, expressed with the following formula:[7]where,C tABS100%2.4NCtis the number of counts recorded per unit time integrated over the wholerecorded spectrum, andtime.Nis calculated from:Nis the number of gamma rays emitted by the source per unitN D I E )2.5s ( Where,D is the disintegration rate of the source and I E ) is the fractional gammass( emitted per disintegration [7].Intrinsic efficiency is subdivided into two classes: intrinsic total efficiency andintrinsic photopeak efficiency. Intrinsic total efficiency, i, is defined as the percentageof radiation quanta incident on the detector, that are recorded and is expressed throughthe following formula:C ti 100%2.6NWhere,N is the total number of gamma rays that are incident on the detector and canbe calculated through the following expression:N DsI( E) N2.744Where, Ω is the solid angle subtended by the detector at the source position [7].K. Suren 10