Background Helium-3-filled linear position-sensitive detectors(LPSDs)have been widely applied to neutron scattering instruments in recent decades owing to the high detection efficiency,the excellent neutron/gamma disc...Background Helium-3-filled linear position-sensitive detectors(LPSDs)have been widely applied to neutron scattering instruments in recent decades owing to the high detection efficiency,the excellent neutron/gamma discrimination,and the ability to construct the detector with large area coverage.More than 65%of neutron instruments at the China Spallation Neutron Source(CSNS)require ^(3)He LPSDs for the building of the detector system.The detector of a neutron scattering instrument is normally an array detector composed of a large number of ^(3)He LPSDs.However,no appropriate substitute detector is available for the ^(3)He LPSD for operation over a short period,and its specifications need to be customized to satisfy the requirements of different instruments.This necessitates the development of ^(3)He LPSDs with different specifications for building and upgrading the detectors of neutron scattering instruments at CSNS.Purpose To meet the general requirements specified by the neutron instruments at CSNS,a ^(3)He LPSD was developed and its performances were investigated by using the neutron beam.Methods The neutron beam experiments for this ^(3)He LPSD,including measurements of counting rate plateau curve,position calibration,and position resolution along the tube path,were carried out at the beamline-20 of CSNS.To evaluate its performance in the instrument operation,a detector module made of this ^(3)He LPSD has been installed in the multi-physics instrument(MPI),and the comparison test with the commercial ^(3)He LPSD has been conducted at neutron scattering experiments.Results and conclusion The experimental measurements for this ^(3)He LPSD based on the neutron beam showed that it satisfies the requirements for use in neutron scattering instruments.It reaches a plateau slope of 2.6%/100 V with a plateau range from 1750 to 1950 V and attained a minimal position resolution of 5.3 mm(FWHM),superior to the one achieved by the commercial ^(3)He LPSD.In addition,this ^(3)He LPSD detector module applied to the MPI has been working steadily for half of year and is available for use in experiments.These results provide a sound basis for the subsequent construction and upgradation of the detector of neutron scattering instruments at CSNS.展开更多
Introduction China Spallation Neutron Source(CSNS)is an accelerator-based pulsed neutron source which produces neutron with spallation reaction induced by proton bombarding tungsten target.With increasing beam powers ...Introduction China Spallation Neutron Source(CSNS)is an accelerator-based pulsed neutron source which produces neutron with spallation reaction induced by proton bombarding tungsten target.With increasing beam powers and influences on target,near-target monitoring becomes extreme necessary.In this situation,an optical imaging system for proton beam diagnostics and monitoring near the target is being developed at CSNS,which can provide real-time images of the beam on target and beam distribution information.Target imaging system design and development In the design of CSNS target imaging system,coating of Cr^(3+):Al_(2)O_(3) is used to convert particle radiation into emission light.According to the geometry limits of CSNS target station,a special optical system was designed and fabricated to collect the emission light.When the proton beams strike on the target,the coating on the target will be excited,emitting luminescence at the same time.The mirrors and lenses of the optical system image the distribution of emission light into a radiation-hard imaging fiber,which transmits the images to the GigE camera located at low-dose area outside of the target station.Software was written on the LabView platform to control the camera and analyze the images on line.Mock-up of the imaging system was manufactured to test and evaluate the performances of the system.Some important characteristics of the system were obtained and studied.Conclusion Tests on the mock-up of the system present reliably expectation for beam diagnostics.The imaging system has been installed at CSNS recently.More work will be continued to improve the properties of the system.展开更多
Introduction To set up an online proton beam diagnostic system near the neutron production target of China Spallation Neutron Source(CSNS),a luminescence coating sprayed on the target windowand a corresponding optic s...Introduction To set up an online proton beam diagnostic system near the neutron production target of China Spallation Neutron Source(CSNS),a luminescence coating sprayed on the target windowand a corresponding optic system were fabricated.In the work,the fabrication of Al_(2)O_(3):Cr^(3+) coating was explored.Measurements on the sprayed samples were performed to analyze the characteristics of the Al_(2)O_(3):Cr^(3+) coating.Fabrication and tests of coating samples Three kinds of powders with different Cr concentrations were used to fabricate the luminescence coating samples.The flame spraying,plasma spraying and D-gun spraying processes were explored.Photoluminescence(PL),X-ray diffraction(XRD),scanned electron mirror(SEM)and radioluminescence experiment by 300 MeV deuterium beam were carried out to analyze and characterize the samples.Results The emission spectrum excited by 532-nm laser has two obvious peaks at 692.9 nm and 694.3 nm.The samples by flame spraying process with the powders obtained from melting method show higher luminescence intensity than the samples by plasma spraying process.It is observed that the luminescence intensity has some relationships with the alpha phase in the samples,which is deduced from the XRD and photoluminescence tests results.A lower temperature during the flame spraying process will help to keep more alpha phase in the material.The selected four samples show successful fluoresced results in the radioluminescence experiment.Conclusions The luminescence intensity of the coating is improved greatly by the studies on the fabrication process and the characteristics of the samples.The luminescence coating used in beam diagnostics will be fabricated by the confirmed technical process.More works will be continued to improve the characteristics of the luminescence light by controlling Cr concentration and annealing in 1200∼2000℃ environment in the future.展开更多
基金supported by the National Key R&D Program of China[Grant No.2021YFA1600703]the Strategic Priority Research Program of the Chinese Academy of Sciences[Grant No.XPB23]the National Natural Science Foundation of China[Grant No.12175254].
文摘Background Helium-3-filled linear position-sensitive detectors(LPSDs)have been widely applied to neutron scattering instruments in recent decades owing to the high detection efficiency,the excellent neutron/gamma discrimination,and the ability to construct the detector with large area coverage.More than 65%of neutron instruments at the China Spallation Neutron Source(CSNS)require ^(3)He LPSDs for the building of the detector system.The detector of a neutron scattering instrument is normally an array detector composed of a large number of ^(3)He LPSDs.However,no appropriate substitute detector is available for the ^(3)He LPSD for operation over a short period,and its specifications need to be customized to satisfy the requirements of different instruments.This necessitates the development of ^(3)He LPSDs with different specifications for building and upgrading the detectors of neutron scattering instruments at CSNS.Purpose To meet the general requirements specified by the neutron instruments at CSNS,a ^(3)He LPSD was developed and its performances were investigated by using the neutron beam.Methods The neutron beam experiments for this ^(3)He LPSD,including measurements of counting rate plateau curve,position calibration,and position resolution along the tube path,were carried out at the beamline-20 of CSNS.To evaluate its performance in the instrument operation,a detector module made of this ^(3)He LPSD has been installed in the multi-physics instrument(MPI),and the comparison test with the commercial ^(3)He LPSD has been conducted at neutron scattering experiments.Results and conclusion The experimental measurements for this ^(3)He LPSD based on the neutron beam showed that it satisfies the requirements for use in neutron scattering instruments.It reaches a plateau slope of 2.6%/100 V with a plateau range from 1750 to 1950 V and attained a minimal position resolution of 5.3 mm(FWHM),superior to the one achieved by the commercial ^(3)He LPSD.In addition,this ^(3)He LPSD detector module applied to the MPI has been working steadily for half of year and is available for use in experiments.These results provide a sound basis for the subsequent construction and upgradation of the detector of neutron scattering instruments at CSNS.
基金This work was supported by the China Spalla-tion Neutron Source project,the National Science Foundation of China(Grant Nos.11575289)the Project on the Integration of Indus-try,Education&Research of Guangdong Province,China(Grant No.2015B090901048).
文摘Introduction China Spallation Neutron Source(CSNS)is an accelerator-based pulsed neutron source which produces neutron with spallation reaction induced by proton bombarding tungsten target.With increasing beam powers and influences on target,near-target monitoring becomes extreme necessary.In this situation,an optical imaging system for proton beam diagnostics and monitoring near the target is being developed at CSNS,which can provide real-time images of the beam on target and beam distribution information.Target imaging system design and development In the design of CSNS target imaging system,coating of Cr^(3+):Al_(2)O_(3) is used to convert particle radiation into emission light.According to the geometry limits of CSNS target station,a special optical system was designed and fabricated to collect the emission light.When the proton beams strike on the target,the coating on the target will be excited,emitting luminescence at the same time.The mirrors and lenses of the optical system image the distribution of emission light into a radiation-hard imaging fiber,which transmits the images to the GigE camera located at low-dose area outside of the target station.Software was written on the LabView platform to control the camera and analyze the images on line.Mock-up of the imaging system was manufactured to test and evaluate the performances of the system.Some important characteristics of the system were obtained and studied.Conclusion Tests on the mock-up of the system present reliably expectation for beam diagnostics.The imaging system has been installed at CSNS recently.More work will be continued to improve the properties of the system.
基金Supported by the China Spallation Neutron Source Project,the National Science Foundation of China(Grant Nos.11575289)the Project onthe Integration of Industry,Education&Research of Guangdong Province,China(Grant No.2015B090901048).
文摘Introduction To set up an online proton beam diagnostic system near the neutron production target of China Spallation Neutron Source(CSNS),a luminescence coating sprayed on the target windowand a corresponding optic system were fabricated.In the work,the fabrication of Al_(2)O_(3):Cr^(3+) coating was explored.Measurements on the sprayed samples were performed to analyze the characteristics of the Al_(2)O_(3):Cr^(3+) coating.Fabrication and tests of coating samples Three kinds of powders with different Cr concentrations were used to fabricate the luminescence coating samples.The flame spraying,plasma spraying and D-gun spraying processes were explored.Photoluminescence(PL),X-ray diffraction(XRD),scanned electron mirror(SEM)and radioluminescence experiment by 300 MeV deuterium beam were carried out to analyze and characterize the samples.Results The emission spectrum excited by 532-nm laser has two obvious peaks at 692.9 nm and 694.3 nm.The samples by flame spraying process with the powders obtained from melting method show higher luminescence intensity than the samples by plasma spraying process.It is observed that the luminescence intensity has some relationships with the alpha phase in the samples,which is deduced from the XRD and photoluminescence tests results.A lower temperature during the flame spraying process will help to keep more alpha phase in the material.The selected four samples show successful fluoresced results in the radioluminescence experiment.Conclusions The luminescence intensity of the coating is improved greatly by the studies on the fabrication process and the characteristics of the samples.The luminescence coating used in beam diagnostics will be fabricated by the confirmed technical process.More works will be continued to improve the characteristics of the luminescence light by controlling Cr concentration and annealing in 1200∼2000℃ environment in the future.
