A foil–microchannel plate(MCP)detector,which uses electrostatic lenses and possesses both good position and timing resolutions,has been designed and simulated for beam diagnostics and mass measurements at the next-ge...A foil–microchannel plate(MCP)detector,which uses electrostatic lenses and possesses both good position and timing resolutions,has been designed and simulated for beam diagnostics and mass measurements at the next-generation heavy-ion-beam facility HIAF in China.Characterized by low energy loss and good performances of timing and position measurements,it would be located at focal planes in fragment separator HFRS for position monitoring,beam turning,Bq measurement,and trajectory reconstruction.Moreover,it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(BqDETOF)method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis.Most importantly,the detector can be utilized for in-ring TOF and position measurements,beam-line TOF measurements at two achromatic foci,and position measurements at a dispersive focus of HFRS,thus making it possible to use two complementary mass measurement methods[isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(BqTOF)at the beam-line HFRS]in one single experimental run.展开更多
The low energy particle detector （LEPD） is one of the main payloads onboard the China seismic electromagnetic satellite （CSES）. The detector is designed to ascertain space electrons （0.1–10 MeV） and protons （2...The low energy particle detector （LEPD） is one of the main payloads onboard the China seismic electromagnetic satellite （CSES）. The detector is designed to ascertain space electrons （0.1–10 MeV） and protons （2–50 MeV）. It has the capability of identifying the electrons and protons, to measure the energy spectrum and the incident angle of the particles. The LEPD is made up of a silicon tracker system, a CsI （Tl） mini-calorimeter, an anti-coincidence system made by plastic scintillator, as well as electronics and a data acquisition system （DAQ）. The tracker is also a kind of E-E telescope; it consists of two layers of double-sided silicon strip detectors （DSSD）. The signals emerging from the silicon tracker can be read out by two pieces of application specific integrated circuit （ASIC）, which also can generate an event trigger for the LEPD. The functions of the DSSD system in the LEPD for charged particles were tested by 241Am @5.486 MeV α particles. The results show that the DSSD system works well, and has high performance to detect charged particles and measure the position of incident particles.展开更多
In cases of high radiation emergencies,we propose a surface contamination monitor(SCM)that can quickly measure and pinpoint the contamination distribution in the affected population.Thick gaseous electron multiplier(T...In cases of high radiation emergencies,we propose a surface contamination monitor(SCM)that can quickly measure and pinpoint the contamination distribution in the affected population.Thick gaseous electron multiplier(THGEM)has several advantages,including fast response time and good spatial resolution.Based on new THGEMs,a two-dimensional imaging detector was developed for alpha detection,with a position resolution greater than 3 mm.The detector design and test results are described in this paper.Fast radiation imaging SCMs,with a 40mm×40 mm sensitive area,are currently under development.展开更多
A 2D neutron detector based on 3He convertor and MWPC with an active area of 200 mmx200 mm has been successfully designed and fabricated. The detector has been tested with Am/Be neutron source and with collimated neut...A 2D neutron detector based on 3He convertor and MWPC with an active area of 200 mmx200 mm has been successfully designed and fabricated. The detector has been tested with Am/Be neutron source and with collimated neutron beam with the wavelength of λ=1.37A. The best spatial resolution of 1.18 mm （FWHM） and good linearity were obtained. This is in good agreement with theoretical calculations.展开更多
A 760 mm × 760 mm× 30 mm plastic scintillation detector viewed by photomultiplier tubes （PMTs） from four corners has been developed, and the detector has been tested with cosmic rays and γrays. A position...A 760 mm × 760 mm× 30 mm plastic scintillation detector viewed by photomultiplier tubes （PMTs） from four corners has been developed, and the detector has been tested with cosmic rays and γrays. A position- independent effective time Teff has been found, indicating this detector can be used as a TOF detector. The hit position can also be reconstructed by the time from the four corners.A. TOF resolution of 236 ps and a position resolution of 48 mm have been achieved, and the detection efficiency has also been investigated.展开更多
Efficient calibration methods have been applied to a complex neutron detector array by using the cosmic-ray muons. Through a differential operation on the time difference spectrum, the two edges of this spectrum can b...Efficient calibration methods have been applied to a complex neutron detector array by using the cosmic-ray muons. Through a differential operation on the time difference spectrum, the two edges of this spectrum can be precisely determined, corresponding to the geometrical two ends of the bar, and therefore the relationship between the position and time difference spectrum can be deduced for each bar. The alignment between different bars is realized by choosing cosmic- rays which are perpendicular to the bars. The position resolutions are extracted through a track fitting procedure which uses all tracks detected coincidently by the whole system, together with a simulation analysis. A method is also developed to calibrate the deposited energy by using cosmic-rays at different incident angles.展开更多
The multi-physics instrument(MPI)is the first user cooperative instrument at the China Spallation Neutron Source(CSNS).It was designed to explore the structures of complex materials at multiple scales based on the neu...The multi-physics instrument(MPI)is the first user cooperative instrument at the China Spallation Neutron Source(CSNS).It was designed to explore the structures of complex materials at multiple scales based on the neutron total scattering technique.This imposes the requirements for the detector,including a high detection efficiency to reduce the measurement time and a large solid angle coverage to cover a wide range of momentum transfers.To satisfy these demands,a large-area array of 3He-filled linear position-sensitive detectors(LPSDs)was constructed,each with a diameter of 1 inch and pressure of 20 atm.It uses an orbicular layout of the detector and an eight-pack module design for the arrangement of 3He LPSDs,covering a range of scattering angles from 3°to 170°with a total detector area of approximately 7 m2.The detector works in air,which is separated from the vacuum environment to facilitate installation and maintenance.The characteristics of the MPI detector were investigated through Monte Carlo(MC)simulations using Geant4 and experimental measurements.The results suggest that the detectors are highly efficient in the wavelength range of the MPI,and an efficiency over 25%is achievable for above 0.1 A neutrons.A minimal position resolution of 6.4 mm full width at half maximum(FWHM)along the tube length was achieved at a working voltage of 2200 V,and a deviation below 2 mm between the real and measured positions was attained in the beam experiment.The detector module exhibited good consistency and an excellent counting rate capacity of up to 80 kHz,which satisfied the requirements of experiments with a high event rate.Observations of its operation over the past year have shown that the detector works steadily in sample experiments,which allows the MPI to serve the user program successfully.展开更多
An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, an...An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, and to improve the position determination especially for positions close to the two ends of a long scintillation bar. An overall position resolution of about 3.0 cm （FWHM） was extracted from the residual analysis method and verified by a direct measurement. Energy calibration was also realized by selecting cosmic rays at different incident angles. The bulk light attenuation lengths for the four test bars were also determined. It is demonstrated that these methods are especially efficient for calibrating large and complex detector arrays展开更多
A nonzero intermediate frequency (IF) likelihood acquisition scheme designed for S-band Single Access (SSA) link of China’s Tracking and Data Relay Satellite System (CTDRSS) is introduced. The received signal is down...A nonzero intermediate frequency (IF) likelihood acquisition scheme designed for S-band Single Access (SSA) link of China’s Tracking and Data Relay Satellite System (CTDRSS) is introduced. The received signal is downconverted to IF, and then direct sampled in IF using a 1-bit A/D. After the digitalization, the sampled data is detected using a hybrid likelihood acquisition scheme. Using this structure, large noise figure of the analog mixer or active filters, amplitude and phase imbalance between low-frequency in-phase and quandrature-phase channel can be avoided. An easy designing algorithm of the acquisition scheme is also derived. The performance and algorithm are verified by computer simulation.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11605248,11605249,11605267,and 11805032.)
文摘A foil–microchannel plate(MCP)detector,which uses electrostatic lenses and possesses both good position and timing resolutions,has been designed and simulated for beam diagnostics and mass measurements at the next-generation heavy-ion-beam facility HIAF in China.Characterized by low energy loss and good performances of timing and position measurements,it would be located at focal planes in fragment separator HFRS for position monitoring,beam turning,Bq measurement,and trajectory reconstruction.Moreover,it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(BqDETOF)method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis.Most importantly,the detector can be utilized for in-ring TOF and position measurements,beam-line TOF measurements at two achromatic foci,and position measurements at a dispersive focus of HFRS,thus making it possible to use two complementary mass measurement methods[isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(BqTOF)at the beam-line HFRS]in one single experimental run.
基金Supported by China 863 High Technology Development Program "Study on identification and Quantitative Retriveval of the Lunar Surface Composition" (2010AA122203)
文摘The low energy particle detector （LEPD） is one of the main payloads onboard the China seismic electromagnetic satellite （CSES）. The detector is designed to ascertain space electrons （0.1–10 MeV） and protons （2–50 MeV）. It has the capability of identifying the electrons and protons, to measure the energy spectrum and the incident angle of the particles. The LEPD is made up of a silicon tracker system, a CsI （Tl） mini-calorimeter, an anti-coincidence system made by plastic scintillator, as well as electronics and a data acquisition system （DAQ）. The tracker is also a kind of E-E telescope; it consists of two layers of double-sided silicon strip detectors （DSSD）. The signals emerging from the silicon tracker can be read out by two pieces of application specific integrated circuit （ASIC）, which also can generate an event trigger for the LEPD. The functions of the DSSD system in the LEPD for charged particles were tested by 241Am @5.486 MeV α particles. The results show that the DSSD system works well, and has high performance to detect charged particles and measure the position of incident particles.
基金supported by the China Institute of Atomic Energy and University of Chinese Academy of SciencesNational Natural Science Foundation of China(Nos.11575193 and U1732266)+2 种基金Key Research Program of Frontier Sciences,CAS(No.QYZDB-SSWSLH039)the Youth Innovation Promotion Association of CAS(No.2016153)the Natural Science Key Foundation of Guangxi(No.2015GXNSFDA139002)
文摘In cases of high radiation emergencies,we propose a surface contamination monitor(SCM)that can quickly measure and pinpoint the contamination distribution in the affected population.Thick gaseous electron multiplier(THGEM)has several advantages,including fast response time and good spatial resolution.Based on new THGEMs,a two-dimensional imaging detector was developed for alpha detection,with a position resolution greater than 3 mm.The detector design and test results are described in this paper.Fast radiation imaging SCMs,with a 40mm×40 mm sensitive area,are currently under development.
基金supported by the National Natural Science Foundation of China(Grant No.11127508)
文摘A 2D neutron detector based on 3He convertor and MWPC with an active area of 200 mmx200 mm has been successfully designed and fabricated. The detector has been tested with Am/Be neutron source and with collimated neutron beam with the wavelength of λ=1.37A. The best spatial resolution of 1.18 mm （FWHM） and good linearity were obtained. This is in good agreement with theoretical calculations.
基金Supported by National Natural Science Foundation of China(U1332207,11405242)
文摘A 760 mm × 760 mm× 30 mm plastic scintillation detector viewed by photomultiplier tubes （PMTs） from four corners has been developed, and the detector has been tested with cosmic rays and γrays. A position- independent effective time Teff has been found, indicating this detector can be used as a TOF detector. The hit position can also be reconstructed by the time from the four corners.A. TOF resolution of 236 ps and a position resolution of 48 mm have been achieved, and the detection efficiency has also been investigated.
基金supported by the National Basic Research Program of China (No. 2007CB815002)National Natural Science Foundation of China(Nos. 11035001, 10775003, 10827505, 10821140159)
文摘Efficient calibration methods have been applied to a complex neutron detector array by using the cosmic-ray muons. Through a differential operation on the time difference spectrum, the two edges of this spectrum can be precisely determined, corresponding to the geometrical two ends of the bar, and therefore the relationship between the position and time difference spectrum can be deduced for each bar. The alignment between different bars is realized by choosing cosmic- rays which are perpendicular to the bars. The position resolutions are extracted through a track fitting procedure which uses all tracks detected coincidently by the whole system, together with a simulation analysis. A method is also developed to calibrate the deposited energy by using cosmic-rays at different incident angles.
基金supported by the National Key R&D Program of China (No. 2021YFA1600703)National Natural Science Foundation of China (No. 12175254)Youth Innovation Promotion Association CAS
文摘The multi-physics instrument(MPI)is the first user cooperative instrument at the China Spallation Neutron Source(CSNS).It was designed to explore the structures of complex materials at multiple scales based on the neutron total scattering technique.This imposes the requirements for the detector,including a high detection efficiency to reduce the measurement time and a large solid angle coverage to cover a wide range of momentum transfers.To satisfy these demands,a large-area array of 3He-filled linear position-sensitive detectors(LPSDs)was constructed,each with a diameter of 1 inch and pressure of 20 atm.It uses an orbicular layout of the detector and an eight-pack module design for the arrangement of 3He LPSDs,covering a range of scattering angles from 3°to 170°with a total detector area of approximately 7 m2.The detector works in air,which is separated from the vacuum environment to facilitate installation and maintenance.The characteristics of the MPI detector were investigated through Monte Carlo(MC)simulations using Geant4 and experimental measurements.The results suggest that the detectors are highly efficient in the wavelength range of the MPI,and an efficiency over 25%is achievable for above 0.1 A neutrons.A minimal position resolution of 6.4 mm full width at half maximum(FWHM)along the tube length was achieved at a working voltage of 2200 V,and a deviation below 2 mm between the real and measured positions was attained in the beam experiment.The detector module exhibited good consistency and an excellent counting rate capacity of up to 80 kHz,which satisfied the requirements of experiments with a high event rate.Observations of its operation over the past year have shown that the detector works steadily in sample experiments,which allows the MPI to serve the user program successfully.
基金Supported by National Natural Science Foundation of China (10827505, 11035001, 10775003, 10905002)National Basic Research Program of China (2007CB815002)
文摘An overall irradiation and calibration technique was introduced and applied to a test scintillation detector array. An integral conversion method was used to reduce the nonlinearity of the time difference spectrum, and to improve the position determination especially for positions close to the two ends of a long scintillation bar. An overall position resolution of about 3.0 cm （FWHM） was extracted from the residual analysis method and verified by a direct measurement. Energy calibration was also realized by selecting cosmic rays at different incident angles. The bulk light attenuation lengths for the four test bars were also determined. It is demonstrated that these methods are especially efficient for calibrating large and complex detector arrays
文摘A nonzero intermediate frequency (IF) likelihood acquisition scheme designed for S-band Single Access (SSA) link of China’s Tracking and Data Relay Satellite System (CTDRSS) is introduced. The received signal is downconverted to IF, and then direct sampled in IF using a 1-bit A/D. After the digitalization, the sampled data is detected using a hybrid likelihood acquisition scheme. Using this structure, large noise figure of the analog mixer or active filters, amplitude and phase imbalance between low-frequency in-phase and quandrature-phase channel can be avoided. An easy designing algorithm of the acquisition scheme is also derived. The performance and algorithm are verified by computer simulation.
