Background:The Einstein Probe mission is an astronomical satellite developed in China,focusing on time-domain astronomy in the soft X-ray energy band.A key payload of this mission is the follow-up X-ray telescope(FXT)...Background:The Einstein Probe mission is an astronomical satellite developed in China,focusing on time-domain astronomy in the soft X-ray energy band.A key payload of this mission is the follow-up X-ray telescope(FXT),which is the result of international collaboration between China and Europe.The FXT features gold-coated nickel Wolter-I-type focusing mirrors and utilizes PNCCD detectors for imaging and spectroscopy in the focal plane.Methods:We reviewed the seven-year development history of the FXT.Initially,the configuration of the FXT consisted of a single telescope unit in 2017,but it later evolved into a dual-unit setup.Building on the successful design of eROSITA,the FXT team has innovatively introduced new operational modes for the PNCCD.FXT team also developed an ultra-compact helium pulse tube refrigerator,which cools the PNCCD down to-90℃.Additionally,various passive shielding measures have been implemented to protect against high-energy charged particles and enhance radiation resistance.These advancements have significantly improved the overall performance and reliability of the FXT.Results and conclusion:The ground calibrations and tests of the FXT demonstrate that its primary performance meets the established design goals.The FXT has exhibited outstanding performance in orbit,establishing itself as one of the space X-ray telescopes with considerable international influence.展开更多
Purpose The Einstein Probe(EP)satellite is a science mission of the Chinese Academy of Sciences,which is dedicated to time-domain astronomy and high-energy astrophysics.The X-ray baffle is a crucial component of follo...Purpose The Einstein Probe(EP)satellite is a science mission of the Chinese Academy of Sciences,which is dedicated to time-domain astronomy and high-energy astrophysics.The X-ray baffle is a crucial component of follow-up X-ray telescope(FXT),which is an important payload onboard EP.It was designed to efficiently reduce stray light,especially single reflection on the hyperboloid of Wolter-I Mirrors.Methods In this paper,based on the parameters of FXT's mirror module and the detector,the design parameters of the X-ray baffle are optimized through preliminary design and detailed ray-tracing simulation.Fabrication involved precision laser cutting,roll forming,laser welding and integration processes.The thermal stability and mechanical environment adaptability were validated through thermal cycling and mechanical vibration tests.Finally,the X-ray baffle was mounted onto the mirror module with alignment precisely controlled using optical methods.Results The height of the X-ray baffle ranges from 60 to 120 mm from the outside to the inside;the aperture corresponds to each layer of the mirror module.In order to reduce weight and reduce light occlusion,the thickness of each thin shell is 0.125 mm.The ray-tracing simulation results with X-ray baffle are shown that the stray light is effectively reduced in the effective region of the detector.The Eigen-frequency change of the X-ray baffle after the thermal cycle test and mechanical vibration tests is only 0.52%and 0.77%,respectively.The results proved that X-ray baffle has a high thermo-mechanical reliability.The half power diameter(HPD)of the mirror module remained unchanged on-axis with/without X-ray baffle.Conclusion The introduction of X-ray baffle is expected to be highly significantly reduce stray light.展开更多
Purpose This study aimed to optimize the pre-treatment process for electroless nickel-phosphorus plating in the Einstein Probe project,addressing technical challenges encountered with 6061 aluminum alloy substrates to...Purpose This study aimed to optimize the pre-treatment process for electroless nickel-phosphorus plating in the Einstein Probe project,addressing technical challenges encountered with 6061 aluminum alloy substrates to enhance coating quality and operational efficiency.Methods Verification experiments were conducted using 6061 aluminum alloy sheets as substitutes for large aluminum mandrels.The effects of surface roughness,rinsing methods,and the necessity of acid pickling were systematically evaluated.The samples were characterized by scanning electron microscopy,atomic force microscopy,and energy-dispersive X-ray spectroscopy to analyze surface morphology and elemental composition.Results and Conclusion Excessive surface roughness should be avoided,with a roughness below 338 nm ensuring uniform coatings.Flowing water rinsing after each step was critical to prevent contamination from residual solutions,whereas stagnant water immersion proved inadequate.Acid pickling was determined to be non-essential,as it had minimal impact on coating quality.The zinc layer formed during immersion exhibited weak adhesion and should be rinsed gently to avoid detachment.These findings offer valuable insights for pre-treatment process refinement in the Einstein Probe project and related applications.展开更多
Purpose The purpose of the study was to prepare and evaluate the performance of graphite/copper composites in accelerators.Methods A series of graphite/copper composites were prepared by powder metallurgy.Based on the...Purpose The purpose of the study was to prepare and evaluate the performance of graphite/copper composites in accelerators.Methods A series of graphite/copper composites were prepared by powder metallurgy.Based on the relative density,bending strength,thermal conductivity,linear expansion coefficient,steady-state stability normalized index(SSNI),and electrical conductivity,the ratio of graphite/copper in the composites was optimized.Results The type of graphite greatly influenced the properties of the resulting graphite/copper composites.Compared with flake graphite/copper,spherical graphite/copper had a higher bending strength,thermal conductivity coefficient,SSNI,and conductivity.Although the dopant did not react with graphite,it greatly impacted the properties of the graphite/copper composite.Increasing the graphite content after doping with Ti and Ni resulted in a higher thermal conductivity and SSNI compared with the undoped or mono-doped composites.The graphite content greatly influenced the thermal conductivity of the composite.When the graphite content did not exceed 40 vol%,the thermal conductivity of the graphite/copper composite changed only slightly with the temperature.When the graphite content exceeded 45 vol%,the thermal conductivity of the graphite/copper composite decreased with temperature.Conclusion Among the prepared graphite/copper composites,titanium/nickel/spherical graphite/copper with a spherical graphite content of 50 vol%had the largest SSNI,which was higher than that of copper.Under specific conditions,it may be used as a substitute for copper in collimators or beam dumps.Different graphite/copper composites showed different coefficients of linear expansion,with a reasonable allocation of graphite and dopants.These composites may be used as transition layers in the brazing connection of large graphite and copper-based materials.展开更多
The Einstein Probe(EP)is a space X-ray astronomical mission led by Chinese Academy of Sciences(CAS)in collaboration with Europe.It was successfully launched into a low-Earth orbit with an altitude of 580 km and an inc...The Einstein Probe(EP)is a space X-ray astronomical mission led by Chinese Academy of Sciences(CAS)in collaboration with Europe.It was successfully launched into a low-Earth orbit with an altitude of 580 km and an inclination of 29 degrees on January 9,2024.Its primary objectives are to discover and characterize X-ray transients in the universe,observe outbursts from dormant black holes,and search for X-ray counterparts of gravitational wave events.展开更多
1.Aims and scope.Radiation Detection Technology and Methods(RDTM)focuses on all aspects of radiation detection technology and methods,including electronics and system design,computer and control techniques,detection t...1.Aims and scope.Radiation Detection Technology and Methods(RDTM)focuses on all aspects of radiation detection technology and methods,including electronics and system design,computer and control techniques,detection technology and methods,data processing and imaging.It presents an attractive mix of authoritative and comprehensive reviews,original articles on cutting-edge research and brief communications.The journal offers rapid review and publication of articles.展开更多
1.Aimsand scope.Radiation Detection Technology and Methods(RDTM)focuses on all aspects of radiation detection technology and methods,including electronics and system design,computer and control techniques,detection te...1.Aimsand scope.Radiation Detection Technology and Methods(RDTM)focuses on all aspects of radiation detection technology and methods,including electronics and system design,computer and control techniques,detection technology and methods,data processing and imaging.It presents an attractive mix of authoritative and comprehensive reviews,original articles on cutting-edge research and brief communications.The journal offers rapid review and publication of articles.展开更多
The Einstein Probe(EP)satellite represents a significant milestone in China's pursuit of advancing time-domain astronomy and high-energy astrophysics.At its core lies the Follow-up X-ray Telescope(FXT),a groundbre...The Einstein Probe(EP)satellite represents a significant milestone in China's pursuit of advancing time-domain astronomy and high-energy astrophysics.At its core lies the Follow-up X-ray Telescope(FXT),a groundbreaking payload that marks China's first foray into Wolter-I focusing technology for X-ray imaging.Designed with a dual-telescope structure,FXT incorporates 54 layers of ultra-smooth,gold-coated nickel mirror shells nested within each focusing mirror,paired with an advanced PNCCD focal plane detector,coupled with an advanced PNCCD focal plane detector.展开更多
This study presents a mathematical model for the peak efficiency of a coaxial high-purity germanium detector using the Monte Carlo code(MCNP),based on data provided by the manufacturer.Consequently,the detector’s mod...This study presents a mathematical model for the peak efficiency of a coaxial high-purity germanium detector using the Monte Carlo code(MCNP),based on data provided by the manufacturer.Consequently,the detector’s model is optimized using a trial-and-error methodology,either by increasing/decreasing the dead layer thickness,aligning the peak efficiency results with experimental measurements.Results indicate that,over 15 years of continuous operation,the dead layer is approximately twice as thick as initially quoted by the manufacturer.Therefore,the dead layer results would confirm that it is crucial to regularly optimize the dead layer over time,as the operator needs to address potential occasional changes.The results indicate that the optimized MC model is suitable for calculating the activity of point/volumetric radioactive sources,with relative errors of 4.40 and 3.23%,respectively.Moreover,this work discusses the different factors that affect the accuracy of the absolute efficiency calibration of gamma spectrometers.展开更多
Correction to:Radiation Detection Technology and Methods(2024)8:1486-1495.https://doi.org/10.1007/s41605-024-00470-z.In this article Methods section of the publication,the term(beamline scientific data acquisition sys...Correction to:Radiation Detection Technology and Methods(2024)8:1486-1495.https://doi.org/10.1007/s41605-024-00470-z.In this article Methods section of the publication,the term(beamline scientific data acquisition system)is incorrectly written and redundant,it has been removed.展开更多
Purpose The follow-up X-ray telescope(FXT)is one of the two payloads of the Einstein Probe(EP),consisting of the upper composite with the X-ray mirror module as the core,the lower composite with the pnCCD module as th...Purpose The follow-up X-ray telescope(FXT)is one of the two payloads of the Einstein Probe(EP),consisting of the upper composite with the X-ray mirror module as the core,the lower composite with the pnCCD module as the core,and the interface structure.The FXT thermal control subsystem is responsible for the thermal design,thermal implementations,and testing of the entire FXT payload thermal control.Methods A design approach is adopted with passive thermal control technology as the main method and active thermal control technology as a supplement for common components.The X-ray mirror modules are high-precision optical components,utilizing active closed-loop temperature control to ensure high precision and stability.The pnCCD detectors operate at a stable low temperature,with refrigerators used to cool the detector houses,ensuring they can operate under stable low-temperature conditions.The hot ends of the refrigerators are connected to the external radiator panels through heat pipes for heat dissipation.Results The thermal control subsystem of FXT is operating properly in-orbit.All component temperatures meet the design requirements.Conclusion After multiple rounds of design and test verification,FXT was successfully launched with EP and completed in-orbit testing.During the in-orbit testing phase of EP,the function of the FXT thermal control subsystem works well.The temperatures of the components and units are normal.This paper introduces the design of FXT thermal control and the in-orbit performance of the thermal control subsystem.展开更多
The Einstein Probe(EP)mission,approved by the Chinese Academy of Sciences(CAS)in 2017 and launched in 2024,is a significant advancement in time-domain astronomy.The Follow-up X-ray Telescope(FXT),equipped with a Wolte...The Einstein Probe(EP)mission,approved by the Chinese Academy of Sciences(CAS)in 2017 and launched in 2024,is a significant advancement in time-domain astronomy.The Follow-up X-ray Telescope(FXT),equipped with a Wolter I focusing mirror system and a PNCCD detector,is critical for detecting and analyzing cosmic X-rays.To ensure its reliability in space,structural and structural-thermal models were developed,and mechanical and thermal tests were conducted to verify its ability to withstand launch stresses and space conditions.The Wolter I mirrors,manufactured and integrated by the HIT team,achieved an angular resolution of 57 arcseconds at 1.5 keV and an effective area of 250 cm^(2).This paper presents the verification results of these tests,including insights from the flight spare model,and discusses potential reasons for the observed loss of effective area,such as alignment imperfections or thermal distortions.These findings are essential for optimizing the FXT’s design and ensuring the mission’s success,highlighting the importance of rigorous testing in space-based observatory development.展开更多
PandaX-4T is a xenon-based multi-purpose experiment,focusing on particle and astrophysics research.The data quality monitoring system plays a crucial role in the experiment.This system enables the prompt detection of ...PandaX-4T is a xenon-based multi-purpose experiment,focusing on particle and astrophysics research.The data quality monitoring system plays a crucial role in the experiment.This system enables the prompt detection of potential issues during data collection.In order to meet the upgrade requirements of the experiment,we have implemented several updates to improve overall data throughput and provide users with more comprehensive information.As a result,the system is capable of monitoring half of the collected data in future operations of the PandaX-4T experiment.Furthermore,with updated hardware,the system is also well equipped to meet the requirements of the future multi-ten-tonne-level PandaX-xT experiment.展开更多
Background Optical fiber radioluminescence measurement(OFRLM)is a cutting-edge technique poised to play a major role in radiation detection and dosimetry.Time-resolved measurement involves capturing the temporal dynam...Background Optical fiber radioluminescence measurement(OFRLM)is a cutting-edge technique poised to play a major role in radiation detection and dosimetry.Time-resolved measurement involves capturing the temporal dynamics of light emission from scintillators,providing detailed information about radiation pulses.Objective This review aims to evaluate various scintillator materials used in time-resolved OFRLM systems and their critical importance in capturing ionizing radiation pulses.Content The article discusses the properties of scintillator materials,including organic,inorganic,and composite compositions,and highlights their unique properties and suitability for time-resolved measurements with OFRLM systems.Performance characteristics,advantages,and limitations of different scintillator materials are thoroughly reviewed.Conclusion This review provides insights into the optimal selection of scintillator materials for time-resolved OFRLM systems,offering criteria for improving their performance and facilitating advancements in radiation detection and dosimetry.展开更多
Purpose This study is part of the Balqarad system's commissioning project.Optimizing the radioactivity detection and measurement using the Balqarad setup is highly important to investigate and explain the self-ind...Purpose This study is part of the Balqarad system's commissioning project.Optimizing the radioactivity detection and measurement using the Balqarad setup is highly important to investigate and explain the self-induced and ambient backgrounds to determine the actual sample-related features in the spectra acquired.Methods Balqarad is a radiation detection system composed of a clover,a variety of scintillators,lead shielding,and the standard electronics needed for the construction of gamma spectra.Four distinct setup configurations were set up to measure background radiation using a tailored analysis code.Results Background radiation from Balqarad components was assessed using two-dimensional background spectra features(hotspots and lines).Background sources in the system’s proximity were studied using one-dimensional spectra in both direct(single)and addback modes.Furthermore,these spectra were crucial in detecting and investigating any potential ^(207)Bi contamination of the bismuth germanium oxide(BGO)material.The results show that the decay from ^(211+211m)Po to the energy levels of ^(207m)Pb was measured,and this could be incorrectly interpreted as the decay of ^(207)Bi.Another noteworthy finding is the presence of a 59.5 keV peak,which was a significant contribution from the shielding to the detector’s background.This study also confirmed the detection of the cosmic peak of ^(74*)Ge generated by the(n,γ)reaction at 596.5 keV in the Ge-BGO system.Conclusion The technique was applied for Balqarad setup components in different configurations for background measurement.The study applied a coincidence/anticoincidence technique to the various configurations,resulting in a reduced cosmic background and the Compton continuum by a factor of 53%.展开更多
Introduction The 2 K laminated-finned heat exchanger(Lf-HX)enhances the efficiency of 2 K superfluid helium production,a pivotal equipment in the cryogenic system of the China Initiative Accelerator Driven System(CiAD...Introduction The 2 K laminated-finned heat exchanger(Lf-HX)enhances the efficiency of 2 K superfluid helium production,a pivotal equipment in the cryogenic system of the China Initiative Accelerator Driven System(CiADS).Materials and Methods This study utilizes computational fluid dynamics(CFD)simulations and experimental methods to investigate the impact of environmental heat leaks,ranging from 0 to 15 W,and flow rates from 1 to 5 g/s on the Lf-HX’s performance.Conclusion The results show that the heat exchanger’s effectiveness declines with increased flow rates under low heat leakage conditions,but this trend inverts under higher heat leakage scenarios.CFD and experimental data reveal that the axial heat leakage of the Lf-HX is 10 W/m2,and higher heat leakage reduces Lf-HX’s robustness.This study provides valuable data for the design and optimization of similar 2 K heat exchangers.展开更多
Purpose The Einstein Probe(EP)satellite is a space X-ray satellite for time-domain astronomy and high-energy astrophysics.The precision control of the optical structure directly affects the imaging quality and positio...Purpose The Einstein Probe(EP)satellite is a space X-ray satellite for time-domain astronomy and high-energy astrophysics.The precision control of the optical structure directly affects the imaging quality and positioning accuracy of the Follow-up X-ray Telescope(FXT),playing a crucial role in achieving the on-orbit scientific objectives of the FXT.Higher positioning accuracy makes it easier to identify corresponding bodies for the discovery and positioning of transient sources.Accurate positioning is beneficial for follow-up observations in other bands,such as optical spectroscopy.Methods This article mainly introduces the precision control methods and processes of the FXT optical structure,which have been tested and verified through satellite test.The on-orbit source positioning accuracy of the FXT telescope is within 20 arcseconds(90% confidence level),meeting the requirements of the FXT mission.Results and Conclusion To ensure the accuracy of the EP satellite’s FXT optical structure,measures such as component processing control,installation control,and posttest adjustments are taken on the ground to ensure that the detector mounting position,optical axis deviation,and other precision indicators before and after the satellite lever test meet the design requirements.After a successful launch,through on-orbit calibration,the FXT-A and FXT-B optical axis pointing direction deviation is 39 arcseconds,and the source positioning error is better than 3'' at 68% confidence level.FXT optical structure meets all the requirements from design,processing,installation,etc.,successfully meeting scientific needs.展开更多
Background With the widespread application of machine learning in neutron-gamma(n-γ)scenarios,assessing the performance and applications of machine learning in real-time discrimination scenarios has significant pract...Background With the widespread application of machine learning in neutron-gamma(n-γ)scenarios,assessing the performance and applications of machine learning in real-time discrimination scenarios has significant practical importance.LabVIEW enables tight integration of data with hardware,facilitating rapid prototyping and customizable development.The k-nearest neighbor(KNN)algorithm is a fundamental and straightforward technique in machine learning.Purpose Optimizing KNN to achieve enhanced accuracy and superior real-time performance in n-γ discrimination,developing a virtual instrument platform to provide researchers with a more convenient method for studying real-time n-γ discrimination algorithms without the need for physical experiments.Method Firstly,this study uses a Gaussian mixture model(GMM)to obtain the training set.Then,we implement the K-nearest neighbor(KNN)algorithm in the LabVIEW programming environment.Finally,the model is deployed on a development computer with a field-programmable gate array(FPGA).By comparing the classification accuracy of GMM-KNN with that of charge comparison method(CCM)in the feature space,we effectively address the issue of inaccurate labeling for pulses in the low-energy domain.Results and conclusion Experimental results demonstrate that KNN correctly classifies 5.52% of gamma rays,showing higher accuracy than CCM,with an average pulse processing time of only 67μs,indicating substantial real-time performance.Using a development computer equipped with a FPGA terminal,KNN not only achieves higher precision real-time n-γ discrimination but also provides a virtual instrument platform for n-γ discrimination.展开更多
Purpose As a high-intensity hadron accelerator-based user facility,minimizing the radiation dose induced by uncontrollable beam loss at the China Spallation Neutron Source(CSNS)is crucial for manual maintenance by ope...Purpose As a high-intensity hadron accelerator-based user facility,minimizing the radiation dose induced by uncontrollable beam loss at the China Spallation Neutron Source(CSNS)is crucial for manual maintenance by operators.A correlation has been observed between the beam transmission efficiency of the Rapid Cycling Synchrotron(RCS)and outdoor temperature.Given that the only RCS components located outdoors are the resonant power supply systems,further investigation into this relationship is necessary to identify opportunities for improving beam transmission efficiency during operation.Methods To address the nonlinear relationship between the resonant power supply variables(amplitude and phase)and beam transmission efficiency,this study employs machine learning techniques.Decision Tree-based algorithms,including Extra Trees,Gradient Boosting Decision Trees(GBDT),Random Forest,and LightGBM,are used for the analysis.These methods enable a statistical examination of the most influential factors affecting beam transmission efficiency in the RCS,with a focus on the amplitude and phase of the resonant power supply.Results The analysis highlights the significance of two amplitudes from higher-order harmonic components in affecting transmission efficiency.It is suggested that increasing the RCS transmission efficiency can be achieved by adjusting these critical amplitudes.Conclusion Adjusting the K3 amplitude of QPS02 and the K2 amplitude of BPS01 has the potential to significantly improve beam transmission efficiency in the RCS,contributing to more efficient operations.展开更多
Purpose The high-precision detection of vertex detectors in the circular electron positron collider(CEPC)has been a research focus in high-energy physics.However,the vibration characteristics of these detectors under ...Purpose The high-precision detection of vertex detectors in the circular electron positron collider(CEPC)has been a research focus in high-energy physics.However,the vibration characteristics of these detectors under external excitations have not been thoroughly studied.Methods To achieve extremely high spatial resolution,the vertex detector supports(hereafter referred to as the supports)are designed to be lightweight and thin.This study employs theoretical analysis and numerical simulation methods,proposing a multi-objective genetic algorithm to optimize the structural stiffness.The optimized structure is validated through modal analysis and computational fluid dynamics.Results The inner and middle supports exhibit good rigidity,with the first natural frequency exceeding 100 Hz.However,the first natural frequency of the outer support is less than 100 Hz.When subjected to cooling fluid impacts at a flow rate of 4 m/s or higher,this can easily lead to structural resonance.At airflow rates of 2 m/s and 3 m/s,the ratio of the excitation frequency to the natural frequency of the structure exceeds 0.6,resulting in significant vibration amplification.Conclusion The outer support exhibits significant vibration amplification under the impact of cooling airflow at different speeds.By optimizing the structural dimensions and cooling airspeed while ensuring lightweight and structural integrity,this study effectively mitigates the vibration amplification phenomenon in the outer support induced by fluid excitation.展开更多
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA 15310103).
文摘Background:The Einstein Probe mission is an astronomical satellite developed in China,focusing on time-domain astronomy in the soft X-ray energy band.A key payload of this mission is the follow-up X-ray telescope(FXT),which is the result of international collaboration between China and Europe.The FXT features gold-coated nickel Wolter-I-type focusing mirrors and utilizes PNCCD detectors for imaging and spectroscopy in the focal plane.Methods:We reviewed the seven-year development history of the FXT.Initially,the configuration of the FXT consisted of a single telescope unit in 2017,but it later evolved into a dual-unit setup.Building on the successful design of eROSITA,the FXT team has innovatively introduced new operational modes for the PNCCD.FXT team also developed an ultra-compact helium pulse tube refrigerator,which cools the PNCCD down to-90℃.Additionally,various passive shielding measures have been implemented to protect against high-energy charged particles and enhance radiation resistance.These advancements have significantly improved the overall performance and reliability of the FXT.Results and conclusion:The ground calibrations and tests of the FXT demonstrate that its primary performance meets the established design goals.The FXT has exhibited outstanding performance in orbit,establishing itself as one of the space X-ray telescopes with considerable international influence.
基金supported by the Natural Science Basic Research Program of Shaanxi Province(2024JC-YBMS-532)the Natural Science Basic Research Program of Shaanxi Province(2023-JC-ZD-40)+1 种基金the Natural Science Basic Research Program of Shaanxi Province(2024JC-YBQN-0003)the Natural Science Basic Research Program of Shaanxi Province(2024JC-YBQN-0686).
文摘Purpose The Einstein Probe(EP)satellite is a science mission of the Chinese Academy of Sciences,which is dedicated to time-domain astronomy and high-energy astrophysics.The X-ray baffle is a crucial component of follow-up X-ray telescope(FXT),which is an important payload onboard EP.It was designed to efficiently reduce stray light,especially single reflection on the hyperboloid of Wolter-I Mirrors.Methods In this paper,based on the parameters of FXT's mirror module and the detector,the design parameters of the X-ray baffle are optimized through preliminary design and detailed ray-tracing simulation.Fabrication involved precision laser cutting,roll forming,laser welding and integration processes.The thermal stability and mechanical environment adaptability were validated through thermal cycling and mechanical vibration tests.Finally,the X-ray baffle was mounted onto the mirror module with alignment precisely controlled using optical methods.Results The height of the X-ray baffle ranges from 60 to 120 mm from the outside to the inside;the aperture corresponds to each layer of the mirror module.In order to reduce weight and reduce light occlusion,the thickness of each thin shell is 0.125 mm.The ray-tracing simulation results with X-ray baffle are shown that the stray light is effectively reduced in the effective region of the detector.The Eigen-frequency change of the X-ray baffle after the thermal cycle test and mechanical vibration tests is only 0.52%and 0.77%,respectively.The results proved that X-ray baffle has a high thermo-mechanical reliability.The half power diameter(HPD)of the mirror module remained unchanged on-axis with/without X-ray baffle.Conclusion The introduction of X-ray baffle is expected to be highly significantly reduce stray light.
基金supported by the National Natural Science Foundation of China(Grant Nos.42327802 and 22479035).
文摘Purpose This study aimed to optimize the pre-treatment process for electroless nickel-phosphorus plating in the Einstein Probe project,addressing technical challenges encountered with 6061 aluminum alloy substrates to enhance coating quality and operational efficiency.Methods Verification experiments were conducted using 6061 aluminum alloy sheets as substitutes for large aluminum mandrels.The effects of surface roughness,rinsing methods,and the necessity of acid pickling were systematically evaluated.The samples were characterized by scanning electron microscopy,atomic force microscopy,and energy-dispersive X-ray spectroscopy to analyze surface morphology and elemental composition.Results and Conclusion Excessive surface roughness should be avoided,with a roughness below 338 nm ensuring uniform coatings.Flowing water rinsing after each step was critical to prevent contamination from residual solutions,whereas stagnant water immersion proved inadequate.Acid pickling was determined to be non-essential,as it had minimal impact on coating quality.The zinc layer formed during immersion exhibited weak adhesion and should be rinsed gently to avoid detachment.These findings offer valuable insights for pre-treatment process refinement in the Einstein Probe project and related applications.
基金supported by the National Natural Science Foundation of China(grant Nos.12105296,and 12105308)the Guangdong Provincial Key Laboratory of Extreme Conditions(2023B1212010002).
文摘Purpose The purpose of the study was to prepare and evaluate the performance of graphite/copper composites in accelerators.Methods A series of graphite/copper composites were prepared by powder metallurgy.Based on the relative density,bending strength,thermal conductivity,linear expansion coefficient,steady-state stability normalized index(SSNI),and electrical conductivity,the ratio of graphite/copper in the composites was optimized.Results The type of graphite greatly influenced the properties of the resulting graphite/copper composites.Compared with flake graphite/copper,spherical graphite/copper had a higher bending strength,thermal conductivity coefficient,SSNI,and conductivity.Although the dopant did not react with graphite,it greatly impacted the properties of the graphite/copper composite.Increasing the graphite content after doping with Ti and Ni resulted in a higher thermal conductivity and SSNI compared with the undoped or mono-doped composites.The graphite content greatly influenced the thermal conductivity of the composite.When the graphite content did not exceed 40 vol%,the thermal conductivity of the graphite/copper composite changed only slightly with the temperature.When the graphite content exceeded 45 vol%,the thermal conductivity of the graphite/copper composite decreased with temperature.Conclusion Among the prepared graphite/copper composites,titanium/nickel/spherical graphite/copper with a spherical graphite content of 50 vol%had the largest SSNI,which was higher than that of copper.Under specific conditions,it may be used as a substitute for copper in collimators or beam dumps.Different graphite/copper composites showed different coefficients of linear expansion,with a reasonable allocation of graphite and dopants.These composites may be used as transition layers in the brazing connection of large graphite and copper-based materials.
文摘The Einstein Probe(EP)is a space X-ray astronomical mission led by Chinese Academy of Sciences(CAS)in collaboration with Europe.It was successfully launched into a low-Earth orbit with an altitude of 580 km and an inclination of 29 degrees on January 9,2024.Its primary objectives are to discover and characterize X-ray transients in the universe,observe outbursts from dormant black holes,and search for X-ray counterparts of gravitational wave events.
文摘1.Aims and scope.Radiation Detection Technology and Methods(RDTM)focuses on all aspects of radiation detection technology and methods,including electronics and system design,computer and control techniques,detection technology and methods,data processing and imaging.It presents an attractive mix of authoritative and comprehensive reviews,original articles on cutting-edge research and brief communications.The journal offers rapid review and publication of articles.
文摘1.Aimsand scope.Radiation Detection Technology and Methods(RDTM)focuses on all aspects of radiation detection technology and methods,including electronics and system design,computer and control techniques,detection technology and methods,data processing and imaging.It presents an attractive mix of authoritative and comprehensive reviews,original articles on cutting-edge research and brief communications.The journal offers rapid review and publication of articles.
文摘The Einstein Probe(EP)satellite represents a significant milestone in China's pursuit of advancing time-domain astronomy and high-energy astrophysics.At its core lies the Follow-up X-ray Telescope(FXT),a groundbreaking payload that marks China's first foray into Wolter-I focusing technology for X-ray imaging.Designed with a dual-telescope structure,FXT incorporates 54 layers of ultra-smooth,gold-coated nickel mirror shells nested within each focusing mirror,paired with an advanced PNCCD focal plane detector,coupled with an advanced PNCCD focal plane detector.
文摘This study presents a mathematical model for the peak efficiency of a coaxial high-purity germanium detector using the Monte Carlo code(MCNP),based on data provided by the manufacturer.Consequently,the detector’s model is optimized using a trial-and-error methodology,either by increasing/decreasing the dead layer thickness,aligning the peak efficiency results with experimental measurements.Results indicate that,over 15 years of continuous operation,the dead layer is approximately twice as thick as initially quoted by the manufacturer.Therefore,the dead layer results would confirm that it is crucial to regularly optimize the dead layer over time,as the operator needs to address potential occasional changes.The results indicate that the optimized MC model is suitable for calculating the activity of point/volumetric radioactive sources,with relative errors of 4.40 and 3.23%,respectively.Moreover,this work discusses the different factors that affect the accuracy of the absolute efficiency calibration of gamma spectrometers.
文摘Correction to:Radiation Detection Technology and Methods(2024)8:1486-1495.https://doi.org/10.1007/s41605-024-00470-z.In this article Methods section of the publication,the term(beamline scientific data acquisition system)is incorrectly written and redundant,it has been removed.
基金supported by the Einstein-Probe(EP)Program which is funded by the Strategic Priority Research Program of the Chinese Academy of Sciences Grant No.XDA15310103.
文摘Purpose The follow-up X-ray telescope(FXT)is one of the two payloads of the Einstein Probe(EP),consisting of the upper composite with the X-ray mirror module as the core,the lower composite with the pnCCD module as the core,and the interface structure.The FXT thermal control subsystem is responsible for the thermal design,thermal implementations,and testing of the entire FXT payload thermal control.Methods A design approach is adopted with passive thermal control technology as the main method and active thermal control technology as a supplement for common components.The X-ray mirror modules are high-precision optical components,utilizing active closed-loop temperature control to ensure high precision and stability.The pnCCD detectors operate at a stable low temperature,with refrigerators used to cool the detector houses,ensuring they can operate under stable low-temperature conditions.The hot ends of the refrigerators are connected to the external radiator panels through heat pipes for heat dissipation.Results The thermal control subsystem of FXT is operating properly in-orbit.All component temperatures meet the design requirements.Conclusion After multiple rounds of design and test verification,FXT was successfully launched with EP and completed in-orbit testing.During the in-orbit testing phase of EP,the function of the FXT thermal control subsystem works well.The temperatures of the components and units are normal.This paper introduces the design of FXT thermal control and the in-orbit performance of the thermal control subsystem.
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences,Grant No.XDA1531010301.
文摘The Einstein Probe(EP)mission,approved by the Chinese Academy of Sciences(CAS)in 2017 and launched in 2024,is a significant advancement in time-domain astronomy.The Follow-up X-ray Telescope(FXT),equipped with a Wolter I focusing mirror system and a PNCCD detector,is critical for detecting and analyzing cosmic X-rays.To ensure its reliability in space,structural and structural-thermal models were developed,and mechanical and thermal tests were conducted to verify its ability to withstand launch stresses and space conditions.The Wolter I mirrors,manufactured and integrated by the HIT team,achieved an angular resolution of 57 arcseconds at 1.5 keV and an effective area of 250 cm^(2).This paper presents the verification results of these tests,including insights from the flight spare model,and discusses potential reasons for the observed loss of effective area,such as alignment imperfections or thermal distortions.These findings are essential for optimizing the FXT’s design and ensuring the mission’s success,highlighting the importance of rigorous testing in space-based observatory development.
基金supported by the grants from National Natural Science Foundation of China(No.12175139).
文摘PandaX-4T is a xenon-based multi-purpose experiment,focusing on particle and astrophysics research.The data quality monitoring system plays a crucial role in the experiment.This system enables the prompt detection of potential issues during data collection.In order to meet the upgrade requirements of the experiment,we have implemented several updates to improve overall data throughput and provide users with more comprehensive information.As a result,the system is capable of monitoring half of the collected data in future operations of the PandaX-4T experiment.Furthermore,with updated hardware,the system is also well equipped to meet the requirements of the future multi-ten-tonne-level PandaX-xT experiment.
基金TM R&D(grant number RDTC/241145)for their support of this research.
文摘Background Optical fiber radioluminescence measurement(OFRLM)is a cutting-edge technique poised to play a major role in radiation detection and dosimetry.Time-resolved measurement involves capturing the temporal dynamics of light emission from scintillators,providing detailed information about radiation pulses.Objective This review aims to evaluate various scintillator materials used in time-resolved OFRLM systems and their critical importance in capturing ionizing radiation pulses.Content The article discusses the properties of scintillator materials,including organic,inorganic,and composite compositions,and highlights their unique properties and suitability for time-resolved measurements with OFRLM systems.Performance characteristics,advantages,and limitations of different scintillator materials are thoroughly reviewed.Conclusion This review provides insights into the optimal selection of scintillator materials for time-resolved OFRLM systems,offering criteria for improving their performance and facilitating advancements in radiation detection and dosimetry.
文摘Purpose This study is part of the Balqarad system's commissioning project.Optimizing the radioactivity detection and measurement using the Balqarad setup is highly important to investigate and explain the self-induced and ambient backgrounds to determine the actual sample-related features in the spectra acquired.Methods Balqarad is a radiation detection system composed of a clover,a variety of scintillators,lead shielding,and the standard electronics needed for the construction of gamma spectra.Four distinct setup configurations were set up to measure background radiation using a tailored analysis code.Results Background radiation from Balqarad components was assessed using two-dimensional background spectra features(hotspots and lines).Background sources in the system’s proximity were studied using one-dimensional spectra in both direct(single)and addback modes.Furthermore,these spectra were crucial in detecting and investigating any potential ^(207)Bi contamination of the bismuth germanium oxide(BGO)material.The results show that the decay from ^(211+211m)Po to the energy levels of ^(207m)Pb was measured,and this could be incorrectly interpreted as the decay of ^(207)Bi.Another noteworthy finding is the presence of a 59.5 keV peak,which was a significant contribution from the shielding to the detector’s background.This study also confirmed the detection of the cosmic peak of ^(74*)Ge generated by the(n,γ)reaction at 596.5 keV in the Ge-BGO system.Conclusion The technique was applied for Balqarad setup components in different configurations for background measurement.The study applied a coincidence/anticoincidence technique to the various configurations,resulting in a reduced cosmic background and the Compton continuum by a factor of 53%.
基金financially supported by the Strategically leading scientific and technological project of the Chinese Academy of Sciences(No:E12G821Y)the Large Research Infrastructures China initiative Accelerator Driven System(No:2017-000052-75-01-000590).
文摘Introduction The 2 K laminated-finned heat exchanger(Lf-HX)enhances the efficiency of 2 K superfluid helium production,a pivotal equipment in the cryogenic system of the China Initiative Accelerator Driven System(CiADS).Materials and Methods This study utilizes computational fluid dynamics(CFD)simulations and experimental methods to investigate the impact of environmental heat leaks,ranging from 0 to 15 W,and flow rates from 1 to 5 g/s on the Lf-HX’s performance.Conclusion The results show that the heat exchanger’s effectiveness declines with increased flow rates under low heat leakage conditions,but this trend inverts under higher heat leakage scenarios.CFD and experimental data reveal that the axial heat leakage of the Lf-HX is 10 W/m2,and higher heat leakage reduces Lf-HX’s robustness.This study provides valuable data for the design and optimization of similar 2 K heat exchangers.
基金supported by the Strategic Priority Research Program on Space Science,the Chinese Academy of Sciences(Grant No.XDA 15310103).
文摘Purpose The Einstein Probe(EP)satellite is a space X-ray satellite for time-domain astronomy and high-energy astrophysics.The precision control of the optical structure directly affects the imaging quality and positioning accuracy of the Follow-up X-ray Telescope(FXT),playing a crucial role in achieving the on-orbit scientific objectives of the FXT.Higher positioning accuracy makes it easier to identify corresponding bodies for the discovery and positioning of transient sources.Accurate positioning is beneficial for follow-up observations in other bands,such as optical spectroscopy.Methods This article mainly introduces the precision control methods and processes of the FXT optical structure,which have been tested and verified through satellite test.The on-orbit source positioning accuracy of the FXT telescope is within 20 arcseconds(90% confidence level),meeting the requirements of the FXT mission.Results and Conclusion To ensure the accuracy of the EP satellite’s FXT optical structure,measures such as component processing control,installation control,and posttest adjustments are taken on the ground to ensure that the detector mounting position,optical axis deviation,and other precision indicators before and after the satellite lever test meet the design requirements.After a successful launch,through on-orbit calibration,the FXT-A and FXT-B optical axis pointing direction deviation is 39 arcseconds,and the source positioning error is better than 3'' at 68% confidence level.FXT optical structure meets all the requirements from design,processing,installation,etc.,successfully meeting scientific needs.
基金supported by the National Natural Science Foundation of China(No 0.12205062)Guizhou Provincial Science and Technology Plan project(LH[2017]7225).
文摘Background With the widespread application of machine learning in neutron-gamma(n-γ)scenarios,assessing the performance and applications of machine learning in real-time discrimination scenarios has significant practical importance.LabVIEW enables tight integration of data with hardware,facilitating rapid prototyping and customizable development.The k-nearest neighbor(KNN)algorithm is a fundamental and straightforward technique in machine learning.Purpose Optimizing KNN to achieve enhanced accuracy and superior real-time performance in n-γ discrimination,developing a virtual instrument platform to provide researchers with a more convenient method for studying real-time n-γ discrimination algorithms without the need for physical experiments.Method Firstly,this study uses a Gaussian mixture model(GMM)to obtain the training set.Then,we implement the K-nearest neighbor(KNN)algorithm in the LabVIEW programming environment.Finally,the model is deployed on a development computer with a field-programmable gate array(FPGA).By comparing the classification accuracy of GMM-KNN with that of charge comparison method(CCM)in the feature space,we effectively address the issue of inaccurate labeling for pulses in the low-energy domain.Results and conclusion Experimental results demonstrate that KNN correctly classifies 5.52% of gamma rays,showing higher accuracy than CCM,with an average pulse processing time of only 67μs,indicating substantial real-time performance.Using a development computer equipped with a FPGA terminal,KNN not only achieves higher precision real-time n-γ discrimination but also provides a virtual instrument platform for n-γ discrimination.
文摘Purpose As a high-intensity hadron accelerator-based user facility,minimizing the radiation dose induced by uncontrollable beam loss at the China Spallation Neutron Source(CSNS)is crucial for manual maintenance by operators.A correlation has been observed between the beam transmission efficiency of the Rapid Cycling Synchrotron(RCS)and outdoor temperature.Given that the only RCS components located outdoors are the resonant power supply systems,further investigation into this relationship is necessary to identify opportunities for improving beam transmission efficiency during operation.Methods To address the nonlinear relationship between the resonant power supply variables(amplitude and phase)and beam transmission efficiency,this study employs machine learning techniques.Decision Tree-based algorithms,including Extra Trees,Gradient Boosting Decision Trees(GBDT),Random Forest,and LightGBM,are used for the analysis.These methods enable a statistical examination of the most influential factors affecting beam transmission efficiency in the RCS,with a focus on the amplitude and phase of the resonant power supply.Results The analysis highlights the significance of two amplitudes from higher-order harmonic components in affecting transmission efficiency.It is suggested that increasing the RCS transmission efficiency can be achieved by adjusting these critical amplitudes.Conclusion Adjusting the K3 amplitude of QPS02 and the K2 amplitude of BPS01 has the potential to significantly improve beam transmission efficiency in the RCS,contributing to more efficient operations.
文摘Purpose The high-precision detection of vertex detectors in the circular electron positron collider(CEPC)has been a research focus in high-energy physics.However,the vibration characteristics of these detectors under external excitations have not been thoroughly studied.Methods To achieve extremely high spatial resolution,the vertex detector supports(hereafter referred to as the supports)are designed to be lightweight and thin.This study employs theoretical analysis and numerical simulation methods,proposing a multi-objective genetic algorithm to optimize the structural stiffness.The optimized structure is validated through modal analysis and computational fluid dynamics.Results The inner and middle supports exhibit good rigidity,with the first natural frequency exceeding 100 Hz.However,the first natural frequency of the outer support is less than 100 Hz.When subjected to cooling fluid impacts at a flow rate of 4 m/s or higher,this can easily lead to structural resonance.At airflow rates of 2 m/s and 3 m/s,the ratio of the excitation frequency to the natural frequency of the structure exceeds 0.6,resulting in significant vibration amplification.Conclusion The outer support exhibits significant vibration amplification under the impact of cooling airflow at different speeds.By optimizing the structural dimensions and cooling airspeed while ensuring lightweight and structural integrity,this study effectively mitigates the vibration amplification phenomenon in the outer support induced by fluid excitation.
