Chemical vapor deposition(CVD)-grown diamond films have been developed as irradiation-resistant materials to replace or upgrade current detectors for use in extreme radiation environments. However, their sensitivity i...Chemical vapor deposition(CVD)-grown diamond films have been developed as irradiation-resistant materials to replace or upgrade current detectors for use in extreme radiation environments. However, their sensitivity in practical applications has been inhibited by space charge stability issues caused by defects and impurities in pure diamond crystal materials. In this study, two high-quality CVD-grown single-crystal diamond(SCD) detectors with low content of nitrogen impurities were fabricated and characterized. The intrinsic properties of the SCD samples were characterized using Raman spectroscopy, stereomicroscopy, and X-ray diffraction with the rocking curve mode, cathode luminescence(CL), and infrared and ultraviolet-visible-near infrared spectroscopies. After packaging the detectors, the dark current and energy resolution under α particle irradiation were investigated. Dark currents of less than 5 pA at 100 V were obtained after annealing the electrodes, which is comparable with the optimal value previously reported. The detector that uses a diamond film with higher nitrogen content showed poor energy resolution, whereas the detector with more dislocations showed poor charge collection efficiency(CCE). This demonstrates that the nitrogen content in diamond has a significant effect on the energy resolution of detectors, while the dislocations in diamond largely contribute to the poor CCE of detectors.展开更多
This paper presents the first comprehensive simulation study of p-11B fusion reactions in a spherical torus.We developed relevant program modules for fusion reactions based on energetic particle simulation frameworks ...This paper presents the first comprehensive simulation study of p-11B fusion reactions in a spherical torus.We developed relevant program modules for fusion reactions based on energetic particle simulation frameworks and analyzed the two main fusion channels:thermal and beam-thermal.Using EHL-2 design parameters with n_(boron)=007n_(ion)and a hydrogen beam at 200 keV and 1 MW,our simulation indicates that p-11B reactions produce approximately 1.5×10^(15)αparticles per second(~0.7 kW)from the thermal channel,and5.3×10^(14)(~0.25 kW)from the beam-thermal channel.We conducted parameter scans to establish a solid physics foundation for the high ion temperature conditions(T_(i)>26ke V)designed for EHL-2.This work also laid the groundwork for studying various operation modes to explore different reaction channels.The simulation results suggest that the conditions in EHL-2 could be sufficient for investigating p-11B thermonuclear reactions.In addition,we found that EHL-2 offered good confinement for energetic particles,allowing us to research the interactions between these ions and plasmas.This research enhances our understanding of burning plasma physics.展开更多
Purpose The performance of CZT inγ-ray and X-ray detection is growing rapidly in these years.However,there are only a few reports on its utilization inαparticle detection.Therefore,to study the properties of CZT for...Purpose The performance of CZT inγ-ray and X-ray detection is growing rapidly in these years.However,there are only a few reports on its utilization inαparticle detection.Therefore,to study the properties of CZT for detection ofαparticle,a detection system has been manufactured,and a series of simulations have been done.Methods A 22×22×0.7mm^(3) planar CZT detector is deployed to detect theαparticles from a radiation source containing Am-241 and Pu-239,while COMSOL MultiPhysics and GEANT4 are employed in the simulation of charge collection and interaction betweenαparticles and CZT.Results An energy resolution of 1.47%FWHM at 5.486MeV and 1.32%at 5.157MeV has been achieved.A simulated spectrum has been created,and it is analogous to the one from experiment.Conclusion The experiment results show the potential of CZT inαdetection.The simulations are confirmed effective and will guide a better design of the detecting system.展开更多
基金This work was financially supported by the Natural Science Foundation of Beijing,China(No.4192038)National Key Research and Development Program of China(Nos.2016YFE0133200 and 2018YFB0406501)European Union’s Horizon 2020 Research and Innovation Staff Exchange Scheme(No.734578).
文摘Chemical vapor deposition(CVD)-grown diamond films have been developed as irradiation-resistant materials to replace or upgrade current detectors for use in extreme radiation environments. However, their sensitivity in practical applications has been inhibited by space charge stability issues caused by defects and impurities in pure diamond crystal materials. In this study, two high-quality CVD-grown single-crystal diamond(SCD) detectors with low content of nitrogen impurities were fabricated and characterized. The intrinsic properties of the SCD samples were characterized using Raman spectroscopy, stereomicroscopy, and X-ray diffraction with the rocking curve mode, cathode luminescence(CL), and infrared and ultraviolet-visible-near infrared spectroscopies. After packaging the detectors, the dark current and energy resolution under α particle irradiation were investigated. Dark currents of less than 5 pA at 100 V were obtained after annealing the electrodes, which is comparable with the optimal value previously reported. The detector that uses a diamond film with higher nitrogen content showed poor energy resolution, whereas the detector with more dislocations showed poor charge collection efficiency(CCE). This demonstrates that the nitrogen content in diamond has a significant effect on the energy resolution of detectors, while the dislocations in diamond largely contribute to the poor CCE of detectors.
基金supported by ENN Group and ENN Energy Research Institute.
文摘This paper presents the first comprehensive simulation study of p-11B fusion reactions in a spherical torus.We developed relevant program modules for fusion reactions based on energetic particle simulation frameworks and analyzed the two main fusion channels:thermal and beam-thermal.Using EHL-2 design parameters with n_(boron)=007n_(ion)and a hydrogen beam at 200 keV and 1 MW,our simulation indicates that p-11B reactions produce approximately 1.5×10^(15)αparticles per second(~0.7 kW)from the thermal channel,and5.3×10^(14)(~0.25 kW)from the beam-thermal channel.We conducted parameter scans to establish a solid physics foundation for the high ion temperature conditions(T_(i)>26ke V)designed for EHL-2.This work also laid the groundwork for studying various operation modes to explore different reaction channels.The simulation results suggest that the conditions in EHL-2 could be sufficient for investigating p-11B thermonuclear reactions.In addition,we found that EHL-2 offered good confinement for energetic particles,allowing us to research the interactions between these ions and plasmas.This research enhances our understanding of burning plasma physics.
文摘Purpose The performance of CZT inγ-ray and X-ray detection is growing rapidly in these years.However,there are only a few reports on its utilization inαparticle detection.Therefore,to study the properties of CZT for detection ofαparticle,a detection system has been manufactured,and a series of simulations have been done.Methods A 22×22×0.7mm^(3) planar CZT detector is deployed to detect theαparticles from a radiation source containing Am-241 and Pu-239,while COMSOL MultiPhysics and GEANT4 are employed in the simulation of charge collection and interaction betweenαparticles and CZT.Results An energy resolution of 1.47%FWHM at 5.486MeV and 1.32%at 5.157MeV has been achieved.A simulated spectrum has been created,and it is analogous to the one from experiment.Conclusion The experiment results show the potential of CZT inαdetection.The simulations are confirmed effective and will guide a better design of the detecting system.
