IV-E-Deposition.pdf

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1、IV.EnergyDepositionintheDetectorandSpectrumFormationa)chargedparticlesBethe-BlochformuladE4pqe4z2é2m0v2ù-=×NZ×êln-ln(1-b2)-b2údxm0v2ëIûz,v:atomicnumberandvelocityofprojectileN,Z:particledensityandatomicnumberofabsorberIntroductiontoRadiationDetectorsandElectronicsCopyrightÓ1998byHel

2、muthSpielerIV.EnergyDepositionintheDetectorandSpectrumFormationAtbg»3thedifferentialenergylossassumesaminimum(minimumionizingparticles),independentofabsorber.dE/dxvs.Eofprotonsinsilicon100.010.0m]m[keV//dxdE1.00.1110100100010000100000ENERGY[MeV]minimumionizationat23GeVIntroductionto

3、RadiationDetectorsandElectronicsCopyrightÓ1998byHelmuthSpielerIV.EnergyDepositionintheDetectorandSpectrumFormationdE/dxvs.Eofelectronsinsilicon10.0m]m1.0[keV//dxdE0.10.010.101.0010.00100.001000.00ENERGY[MeV]Minimumionizationat~1MeV.Atelectronenergies>50MeVradiativeenergylossdominate

4、s,sothestoppingpowerincreasesmorerapidlybeyondtheenergyofminimumionizationthanforprotons.IntroductiontoRadiationDetectorsandElectronicsCopyrightÓ1998byHelmuthSpielerIV.EnergyDepositionintheDetectorandSpectrumFormationForsmallvelocities(b<<1)2dEæzö-µç÷×NZdxèvøÞdE/dxincreaseswithproje

5、ctilechargesquared2decreaseswithincreasingprojectileenergy(v)increaseswithtargetatomicnumberanddensitydE/dxforalphaparticlesinvariousmaterialsIntroductiontoRadiationDetectorsandElectronicsCopyrightÓ1998byHelmuthSpielerIV.EnergyDepositionintheDetectorandSpectrumFormationdE/dxvs.Eforv

6、ariouschargedparticlesinSiIntroductiontoRadiationDetectorsandElectronicsCopyrightÓ1998byHelmuthSpielerIV.EnergyDepositionintheDetectorandSpectrumFormationdE/dxforlighttoheavychargedparticlesinAl(nearlythesameinSi)(fromNorthcliffeandSchilling,Nucl.DataTablesA7(1970)233)2Notethattheve

7、rticalscaleisnormalizedtoZanddensityr.Incontrasttoparticlesoflowatomicnumber,thespecificenergylossofheavyparticlesinitiallyincreaseswithenergy.Withincreasingvelocity,orbitalelectronsarestrippedfromthenucleus,therebyincreasingtheeffectivechargeoftheprojectile.BeyondthepeakdE/dx,where

8、theprojectilesarefu