A conventional multi-channel pulse amplitude analyzer acquires single energy spectrum,but provides no information on its tendency with time.To address the limitation,we propose a scheme of time-sharing multichannel pu...A conventional multi-channel pulse amplitude analyzer acquires single energy spectrum,but provides no information on its tendency with time.To address the limitation,we propose a scheme of time-sharing multichannel pulse amplitude analyzer(TSMCA).A dual-port random access memory is divided into two storage spaces,one for current energy spectrum data acquisition and another for previous energy spectrum data storage.The two tasks can be performed simultaneously,and the time-related variation tendency of energy spectrum can be obtained.A prototype system of TSMCA is designed.It performs nicely,with maximum channel number of 4096 in capacity of 2^(32)/Ch,minimal time-sharing slice of 25 ms,the differential nonlinearity of <1.5%,and the integral nonlinearity of <0.3%.展开更多
A multi-channel retarding field analyzer(MC-RFA) including two RFA modules and two Langmuir probes to measure the ion and electron temperature profiles within the scrape-off layer was developed for investigations of...A multi-channel retarding field analyzer(MC-RFA) including two RFA modules and two Langmuir probes to measure the ion and electron temperature profiles within the scrape-off layer was developed for investigations of the interplay between magnetic topology and plasma transport at the plasma boundary.The MC-RFA probe for the stellarator W7-X and first measurements at the tokamak EAST was designed.The probe head allows simultaneous multichannel ion temperature as well as for electron temperature measurements.The usability for radial correlation measurements of the measured ion currents is also given.展开更多
Radio frequency/microwave-directed energy sources using wide bandgap SiC photoconductive semiconductors have attracted much attention due to their unique advantages of high-power output and multi-parameter adjustable ...Radio frequency/microwave-directed energy sources using wide bandgap SiC photoconductive semiconductors have attracted much attention due to their unique advantages of high-power output and multi-parameter adjustable ability.Over the past several years,benefitting from the sustainable innovations in laser technology and the significant progress in materials technology,megawatt-class output power electrical pulses with a flexible frequency in the P and L microwave wavebands have been achieved by photoconductive semiconductor devices.Here,we mainly summarize and review the recent progress of the high-power photonic microwave generation based on the SiC photoconductive semiconductor devices in the linear modulation mode,including the mechanism,system architecture,critical technology,and experimental demonstration of the proposed high-power photonic microwave sources.The outlooks and challenges for the future of multi-channel power synthesis development of higher power photonic microwave using wide bandgap photoconductors are also discussed.展开更多
Background Plastic scintillator detectors are rugged and easily manufactured in desired shape,sizes and response time to gamma radiation is prompt as compared with any other scintillator detectors.Being popular these ...Background Plastic scintillator detectors are rugged and easily manufactured in desired shape,sizes and response time to gamma radiation is prompt as compared with any other scintillator detectors.Being popular these detectors are used in radiation monitors one of the application to restrict radioactive material movement.These are used in gross counting mode to know the presence of radioactivity.Therefore secondary survey is required to know the nature of the radionuclides.Purpose The feasibility study of Cylindrical Plastic Scintillator Detector(CPSD)was carried out for the qualitative and quantitative assessment of gamma emitting radionuclides.Methods In this work limited gamma spectrometry was carried out using NE110 equivalent cylindrical plastic scintillating material of 5.1 cm diameter and 100 cm long.CPSD is optically coupled to photomultiplier tube(PMT).The detector signal is processed using preamplifier,shaping amplifier and further analysed by a multi channel analyser(MCA).CPSD gamma spectrum consists of Compton continuum and Gaussian shaped Compton edge energy(λ_(e))appearing as Compton maxima energy(λ_(max)).Photon transport simulation is used to characterizeλ_(max) as a signature for radionuclides emitting gamma energy/energies.In case of unresolved gamma energies,it appears as weighted effective Compton maxima energy.The prominent gamma energies observed across nuclear industries are in the energy range 0.03–3 MeV.It is grouped as low energy,intermediate energy,high energy and ultra-high energy window.The simulated spectrum is obtained suing Gaussian broadening parameters deduced from experimentally measured spectrum.The efficiency response function is developed from simulated response of detector to standard gamma sources under known source detector configurations.Results The mono energetic gamma emitting radioisotopes are identified againstλ_(max) from data library.Qualitative analysis of spectrum is used to discriminate artificial radioactive material from naturally occurring radioactive material using gamma photon,corresponding Compton edge and expected Compton maxima in each energy window.The provisional quantitative assessment is carried out using efficiency deduced from response function.The detection efficiency varies within 1%–0.2%for 0.03 to 3 MeV gamma energies.In this study efficiency for ^(137)Cs source is 0.26%with FWHM 0.092 MeV and the results re within 15%for the measured activity.Estimated sensitivity and spectral dose rate coefficient for CPSD are 77 cps/µR/h and 44.29 nGy/kcps respectively.The MDA or MDL of the most prominent radioisotopes used in nuclear industry are estimated.CPSD showed an ability to detect 149 kBq,^(137)Cs radioisotope at 1 m distance.Conclusion CPSD can be utilised for gamma isotope identification with limited gamma spectroscopy tool in contamination and dose rate measurements monitors.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11375195,11375263,and 11105143)the project of National Magnetic Confinement Fusion Energy Development Research(No.2013GB104003)
文摘A conventional multi-channel pulse amplitude analyzer acquires single energy spectrum,but provides no information on its tendency with time.To address the limitation,we propose a scheme of time-sharing multichannel pulse amplitude analyzer(TSMCA).A dual-port random access memory is divided into two storage spaces,one for current energy spectrum data acquisition and another for previous energy spectrum data storage.The two tasks can be performed simultaneously,and the time-related variation tendency of energy spectrum can be obtained.A prototype system of TSMCA is designed.It performs nicely,with maximum channel number of 4096 in capacity of 2^(32)/Ch,minimal time-sharing slice of 25 ms,the differential nonlinearity of <1.5%,and the integral nonlinearity of <0.3%.
基金funding from the Euratom research and training programme 2014–2018 under grant agreement No.633053supported by the National Magnetic Confinement Fusion Science Program of China under Contracts No.20113GB106003
文摘A multi-channel retarding field analyzer(MC-RFA) including two RFA modules and two Langmuir probes to measure the ion and electron temperature profiles within the scrape-off layer was developed for investigations of the interplay between magnetic topology and plasma transport at the plasma boundary.The MC-RFA probe for the stellarator W7-X and first measurements at the tokamak EAST was designed.The probe head allows simultaneous multichannel ion temperature as well as for electron temperature measurements.The usability for radial correlation measurements of the measured ion currents is also given.
基金supported in part by the National Natural Science Foundation of China(Nos.62071477 and 62101577)the Natural Science Foundation of Hunan Province(No.2021JJ40660)。
文摘Radio frequency/microwave-directed energy sources using wide bandgap SiC photoconductive semiconductors have attracted much attention due to their unique advantages of high-power output and multi-parameter adjustable ability.Over the past several years,benefitting from the sustainable innovations in laser technology and the significant progress in materials technology,megawatt-class output power electrical pulses with a flexible frequency in the P and L microwave wavebands have been achieved by photoconductive semiconductor devices.Here,we mainly summarize and review the recent progress of the high-power photonic microwave generation based on the SiC photoconductive semiconductor devices in the linear modulation mode,including the mechanism,system architecture,critical technology,and experimental demonstration of the proposed high-power photonic microwave sources.The outlooks and challenges for the future of multi-channel power synthesis development of higher power photonic microwave using wide bandgap photoconductors are also discussed.
文摘Background Plastic scintillator detectors are rugged and easily manufactured in desired shape,sizes and response time to gamma radiation is prompt as compared with any other scintillator detectors.Being popular these detectors are used in radiation monitors one of the application to restrict radioactive material movement.These are used in gross counting mode to know the presence of radioactivity.Therefore secondary survey is required to know the nature of the radionuclides.Purpose The feasibility study of Cylindrical Plastic Scintillator Detector(CPSD)was carried out for the qualitative and quantitative assessment of gamma emitting radionuclides.Methods In this work limited gamma spectrometry was carried out using NE110 equivalent cylindrical plastic scintillating material of 5.1 cm diameter and 100 cm long.CPSD is optically coupled to photomultiplier tube(PMT).The detector signal is processed using preamplifier,shaping amplifier and further analysed by a multi channel analyser(MCA).CPSD gamma spectrum consists of Compton continuum and Gaussian shaped Compton edge energy(λ_(e))appearing as Compton maxima energy(λ_(max)).Photon transport simulation is used to characterizeλ_(max) as a signature for radionuclides emitting gamma energy/energies.In case of unresolved gamma energies,it appears as weighted effective Compton maxima energy.The prominent gamma energies observed across nuclear industries are in the energy range 0.03–3 MeV.It is grouped as low energy,intermediate energy,high energy and ultra-high energy window.The simulated spectrum is obtained suing Gaussian broadening parameters deduced from experimentally measured spectrum.The efficiency response function is developed from simulated response of detector to standard gamma sources under known source detector configurations.Results The mono energetic gamma emitting radioisotopes are identified againstλ_(max) from data library.Qualitative analysis of spectrum is used to discriminate artificial radioactive material from naturally occurring radioactive material using gamma photon,corresponding Compton edge and expected Compton maxima in each energy window.The provisional quantitative assessment is carried out using efficiency deduced from response function.The detection efficiency varies within 1%–0.2%for 0.03 to 3 MeV gamma energies.In this study efficiency for ^(137)Cs source is 0.26%with FWHM 0.092 MeV and the results re within 15%for the measured activity.Estimated sensitivity and spectral dose rate coefficient for CPSD are 77 cps/µR/h and 44.29 nGy/kcps respectively.The MDA or MDL of the most prominent radioisotopes used in nuclear industry are estimated.CPSD showed an ability to detect 149 kBq,^(137)Cs radioisotope at 1 m distance.Conclusion CPSD can be utilised for gamma isotope identification with limited gamma spectroscopy tool in contamination and dose rate measurements monitors.