When lead tungstate scintillating crystals are used as dense and fast radiat ors for γ ray detectors in high radiation environment in future high energy a c celerators such as LHC,the main problems are (1) radiation ...When lead tungstate scintillating crystals are used as dense and fast radiat ors for γ ray detectors in high radiation environment in future high energy a c celerators such as LHC,the main problems are (1) radiation hardness is not yet s atisfactory,(2) light yield is low. When some impurities are removed from the raw materials,the origin of radiation damage is not related to the purity of the raw material but to structural defect s produced during the growth process.These defects result from the leakage of le ad ( V c(Pb)) and oxygen ( V o) and introduce local charge unbalance that ea sily traps electrons or holes and act as temporary color centers under irradiati on. So doping different ions to compensate charge and suppress the existing defe cts is necessary.展开更多
Background In this study,three sample detectors have been prepared by using cerium-activated YAG nanoscintillator(Y_(3)Al_(5)O_(12):Ce^(3+))synthesized by sol-gel method and heat-treat at 900°C for 2 h in differe...Background In this study,three sample detectors have been prepared by using cerium-activated YAG nanoscintillator(Y_(3)Al_(5)O_(12):Ce^(3+))synthesized by sol-gel method and heat-treat at 900°C for 2 h in different atmospheres such as vacuum,air and nitrogen.Purpose Many studies about YAG:Ce^(3+)single crystal have been carried out,but the material at the nanoscale remains not enough understood.The objective of the present paper is to investigate the effects of annealing atmosphere on the scintillation properties and identify the suitable atmosphere that allow to design radiation detectors with high scintillation efficiency.Methods In order to accurately assess the scintillation properties,the nanoscintillator sample powders have been designed as a detector,in which,preparation operations such as surface homogenization and efficiency coupling with photomultiplier tube(PMT)window were developed.The study was performed usingγ-rays 662 keV released from137Cs radioactive source,the bi-alkali GDB-4FF PMT was used as a photodetector.Nuclear instrumentation chain was set up in order to collect the pulse height spectra,NaI:Tl single-crystal scintillator was used as a reference detector to estimate the scintillation light yield.The delayed coincidence method was used for measuring the scintillation decay time of nanoscintillator sample detectors.Results The sample detector annealed at vacuum atmosphere exhibits the best scintillation properties,the scintillation light yield was estimated to be 14,600±3400 ph/MeV and the fast component in the scintillation decay was 90 ns.Conclusion The vacuum is the suitable atmosphere which allows the development of radiation detectors with high scintillation efficiency.展开更多
The scintillation properties of a CdMoO_4 crystal have been investigated experimentally.The fluorescence yields and decay times measured from 22 K to 300 K demonstrate that CdMoO_4 crystal is a good candidate for an a...The scintillation properties of a CdMoO_4 crystal have been investigated experimentally.The fluorescence yields and decay times measured from 22 K to 300 K demonstrate that CdMoO_4 crystal is a good candidate for an absorber for a bolometer readout,for both heat and scintillation signals.The results from Monte Carlo studies,taking the backgrounds from 2ν2β of_(42)^(100)Mo(_(48)^(116)Cd) and internal trace nuclides ^(214)Bi and ^(208)Tl into account,show that the expected sensitivity of a CdMoO_4 bolometer for neutrinoless double beta decay experiments with an exposure of 100kg·years is one order of magnitude higher than those of the current sets of the limT_(1/2)^(0νββ) of_(42)^(100)Mo and_(48)^(116)Cd.展开更多
文摘When lead tungstate scintillating crystals are used as dense and fast radiat ors for γ ray detectors in high radiation environment in future high energy a c celerators such as LHC,the main problems are (1) radiation hardness is not yet s atisfactory,(2) light yield is low. When some impurities are removed from the raw materials,the origin of radiation damage is not related to the purity of the raw material but to structural defect s produced during the growth process.These defects result from the leakage of le ad ( V c(Pb)) and oxygen ( V o) and introduce local charge unbalance that ea sily traps electrons or holes and act as temporary color centers under irradiati on. So doping different ions to compensate charge and suppress the existing defe cts is necessary.
文摘Background In this study,three sample detectors have been prepared by using cerium-activated YAG nanoscintillator(Y_(3)Al_(5)O_(12):Ce^(3+))synthesized by sol-gel method and heat-treat at 900°C for 2 h in different atmospheres such as vacuum,air and nitrogen.Purpose Many studies about YAG:Ce^(3+)single crystal have been carried out,but the material at the nanoscale remains not enough understood.The objective of the present paper is to investigate the effects of annealing atmosphere on the scintillation properties and identify the suitable atmosphere that allow to design radiation detectors with high scintillation efficiency.Methods In order to accurately assess the scintillation properties,the nanoscintillator sample powders have been designed as a detector,in which,preparation operations such as surface homogenization and efficiency coupling with photomultiplier tube(PMT)window were developed.The study was performed usingγ-rays 662 keV released from137Cs radioactive source,the bi-alkali GDB-4FF PMT was used as a photodetector.Nuclear instrumentation chain was set up in order to collect the pulse height spectra,NaI:Tl single-crystal scintillator was used as a reference detector to estimate the scintillation light yield.The delayed coincidence method was used for measuring the scintillation decay time of nanoscintillator sample detectors.Results The sample detector annealed at vacuum atmosphere exhibits the best scintillation properties,the scintillation light yield was estimated to be 14,600±3400 ph/MeV and the fast component in the scintillation decay was 90 ns.Conclusion The vacuum is the suitable atmosphere which allows the development of radiation detectors with high scintillation efficiency.
基金Supported by National Natural Science Foundation of China(11275199)
文摘The scintillation properties of a CdMoO_4 crystal have been investigated experimentally.The fluorescence yields and decay times measured from 22 K to 300 K demonstrate that CdMoO_4 crystal is a good candidate for an absorber for a bolometer readout,for both heat and scintillation signals.The results from Monte Carlo studies,taking the backgrounds from 2ν2β of_(42)^(100)Mo(_(48)^(116)Cd) and internal trace nuclides ^(214)Bi and ^(208)Tl into account,show that the expected sensitivity of a CdMoO_4 bolometer for neutrinoless double beta decay experiments with an exposure of 100kg·years is one order of magnitude higher than those of the current sets of the limT_(1/2)^(0νββ) of_(42)^(100)Mo and_(48)^(116)Cd.
