Multiplexing technologies based on superconducting quantum interference devices(SQUIDs) are crucial to cryogenic readout of superconducting transition-edge sensor(TES) arrays. Demands for large-scale TES arrays promot...Multiplexing technologies based on superconducting quantum interference devices(SQUIDs) are crucial to cryogenic readout of superconducting transition-edge sensor(TES) arrays. Demands for large-scale TES arrays promote the development of multiplexing technologies towards large multiplexing factors and low readout noise. The development of multiplexing technologies also facilitates new applications of TES arrays in a wide range of frequencies. Here we summarize different types of SQUID-based multiplexing technologies including time-division multiplexing, code-division multiplexing, frequency-division multiplexing and microwave SQUID multiplexing. The advances and parameter constraints of each multiplexing technology are also discussed.展开更多
Resonators in circuit quantum electrodynamics systems naturally carry multiple modes, which may have non-negligible influence on qubit parameters and device performance. While new theories and techniques are under inv...Resonators in circuit quantum electrodynamics systems naturally carry multiple modes, which may have non-negligible influence on qubit parameters and device performance. While new theories and techniques are under investigation to deal with the multi-mode effects in circuit quantum electrodynamics systems, researchers have proposed novel engineering designs featuring multi-mode resonators to achieve enhanced functionalities of superconducting quantum processors. Here, we propose multi-mode bus coupling architecture, in which superconducting qubits are coupled to multiple bus resonators to gain larger coupling strength. Applications of multi-mode bus couplers can be helpful for improving i SWAP gate fidelity and gate speed beyond the limit of single-mode scenario. The proposed multi-mode bus coupling architecture is compatible with a scalable variation of the traditional bus coupling architecture. It opens up new possibilities for realization of scalable superconducting quantum computation with circuit quantum electrodynamics systems.展开更多
Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the ...Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the neutron capture cross-sectional measurements for the low neutron sensitivity and fast time response.The Back-n white neutron source at China Spallation Neutron Source is the first spallation white neutron source in China,and it is suitable for neutron capture cross-sectional measurement.Materials and methods A C_(6)D_(6)detector system was built in the Back-n experimental station.The pulse height weighting technique was used to determine the system’s detection efficiency.The response to gamma rays of the C_(6)D_(6)detector was measured,and the energy resolution function was determined.Monte Carlo simulation with Geant4 code was carried out to get the weighting function of this C_(6)D_(6)detector system.Additionally,the systematic uncertainty of the weighting function was also determined.Conclusion According to the experimental and simulation results,this C_(6)D_(6)detector system can be used to measure neutron capture cross section.展开更多
The China Spallation Neutron Source is an accelerator-based user facility for neutron,proton,muon applications and so on.The designed proton beam power is 100 kW for the first phase.Overall,the scope of accelerator co...The China Spallation Neutron Source is an accelerator-based user facility for neutron,proton,muon applications and so on.The designed proton beam power is 100 kW for the first phase.Overall,the scope of accelerator control system covers four parts,the global systems,the device layer local controls and remote controls,the high-level applications and services and the integration of conventional facilities.The principle guideline is to adopt as many as possible matured technologies and commercial products in the design and implementation.The control system is based on Experimental Physics and Industrial Control System.VME64x bus is chosen for timing system and fast protection system.PLCs and embedded industrial computers are used in the device layer slow controls.Control System Studio is adopted as the high-level applications.Blade server-based virtualization platform is deployed for the computer system.The accelerator control system was completed in September 2017 and then transited to routine operations.The design,implementation and operation of the accelerator control system are described in this paper.展开更多
The capture cross sections of the ^(169)Tm(n,γ)reaction were measured at the back streaming white neutron beam line(Back-n)of the China Spallation Neutron Source(CSNS)using four C_(6)D_(6) liquid scintillation detect...The capture cross sections of the ^(169)Tm(n,γ)reaction were measured at the back streaming white neutron beam line(Back-n)of the China Spallation Neutron Source(CSNS)using four C_(6)D_(6) liquid scintillation detectors.The background subtraction,normalization,and correction were carefully considered in the data analysis to obtain accurate cross sections.For the resonance at 3.9 eV,the R-matrix code SAMMY was used to determine the resonance parameters with the internal normalization method.The average capture cross sections of ^(169)Tm for energy between 30 and 300 keV were extracted relative to the ^(197)Au(n,γ)reaction.The measured cross sections of the ^(169)Tm(n,γ)reaction were reported in logarithmically equidistant energy bins with 20 bins per energy decade with a total uncertainty of 5.4%-7.0% in this study and described in terms of average resonance parameters using a Hauser-Feshbach calculation with fluctuations.The point-wise cross sections and the average resonance parameters showed fair agreement with the evaluated values of the ENDF/B-Ⅷ.0 library in the energy region studied.展开更多
The^6 Li(n,t)~4 He reaction was measured as the first experiment involving neutron-induced charged particle emission reactions at the CSNS(China Spallation Neutron Source)Back-n white neutron source.The differential c...The^6 Li(n,t)~4 He reaction was measured as the first experiment involving neutron-induced charged particle emission reactions at the CSNS(China Spallation Neutron Source)Back-n white neutron source.The differential cross-sections of the^6 Li(n,t)~4 He reaction at 15 detection angles ranging from 19.2°to 160.8°are obtained from 1.0 eV to 3.0 MeV at 80 neutron energy points;for 50 energy points below 0.1 MeV they are reported for the first time.The results indicate that the anisotropy of the emitted tritium is noticeable above E_n=100 eV.The angle-integrated cross-sections are also obtained.The present differential cross-sections agree in general with the previous evaluations,but there are some differences in the details.More importantly,the present results indicate that the cross-sections of the^6 Li(n,t)~4 He reaction might be overestimated by most evaluations in the 0.5-3.0 MeV region,although they are recommended as standards below 1.0 MeV.展开更多
Differential and angle-integrated cross sections for the 10B(n,α)^7 Li,10B(n,α0)^7 Li and 10B(n,α1)^7 Li^*reactions have been measured at CSNS Back-n white neutron source.Two enriched(90%)10B samples 5.0 cm in diam...Differential and angle-integrated cross sections for the 10B(n,α)^7 Li,10B(n,α0)^7 Li and 10B(n,α1)^7 Li^*reactions have been measured at CSNS Back-n white neutron source.Two enriched(90%)10B samples 5.0 cm in diameter and^85.0μg/cm^2 in thickness each with an aluminum backing were prepared,and back-to-back mounted at the sample holder.The charged particles were detected using the silicon-detector array of the Light-charged Particle Detector Array(LPDA)system.The neutron energy En was determined by TOF(time-of-flight)method,and the valid a events were extracted from the En-Amplitude two-dimensional spectrum.With 15 silicon detectors,the differential cross sections of a-particles were measured from 19.2°to 160.8°.Fitted with the Legendre polynomial series,the(n,a)cross sections were obtained through integration.The absolute cross sections were normalized using the standard cross sections of the 10B(n,α)^7 Li reaction in the 0.3-0.5 MeV neutron energy region.The measurement neutron energy range for the 10B(n,α)^7 Li reaction is 1.0 eV≤En<2.5 Me V(67 energy points),and that for the 10B(n,α0)^7 Li and10B(n,α1)^7 Li^*reactions is 1.0 eV≤En<1.0 MeV(59 energy points).The present results have been analyzed by the resonance reaction mechanism and the level structure of the 11B compound system,and compared with existing measurements and evaluations.展开更多
Purpose In order to increase CSNS beam power from 100 to 500 kW,the linac injection energy needs to be increased from 80 to 300 MeV.The combined layout of superconducting spoke cavities and elliptical cavities will be...Purpose In order to increase CSNS beam power from 100 to 500 kW,the linac injection energy needs to be increased from 80 to 300 MeV.The combined layout of superconducting spoke cavities and elliptical cavities will be adopted to accelerate H−beam to 300 MeV.In this paper,a compact single spoke cavity withΦ50-mm beam aperture was proposed,with the RF performance of the spoke cavity optimized to Ep/Eacc<5,Bp/Eacc<9,as well as the good multipacting behavior.Methods CST Microwave Studio was used to optimize the RF performance(Epeak/Eacc,Bpeak/Eacc,R/Q)with cavity geometry parameters.After electromagnetic design was finished,multipacting behavior was studied with CST Particle Studio module,and cavity shape modification was made to get a reasonable<SEY>value.Results The simulation got optimum results of Epeak/Eacc=4.97 and Bpeak/Eacc=8.42 mT/(MV/m),and the<SEY>max is 1.52 at Eacc=7.74 MV/m.Conclusion A 648 MHzβg=0.4 single spoke cavity with beam apertureΦ50 mm was proposed in the paper.This compact cavity may be a very promising option for CSNS linac upgrading.In addition to the optimization of the RF parameters,the multipacting behavior of the cavity is also studied,and cavity shape is optimized to reduce<SEY>value.展开更多
The neutron total cross section data of^(9)Be are essential in the nuclear structure model research of light nuclei and nuclear power installations.The neutron total cross section of^(9)Be in the 0.3 eV−120 MeV energy...The neutron total cross section data of^(9)Be are essential in the nuclear structure model research of light nuclei and nuclear power installations.The neutron total cross section of^(9)Be in the 0.3 eV−120 MeV energy region has been measured using time-of-flight and transmission methods with the Neutron Total Cross Sectional Spectrometer(NTOX)based on the multi-cell fast fission chamber at the China Spallation Neutron Source(CSNS)-Back-n white neutron source(Back-n).The fission count-neutron energy distributions of ^(235)U and ^(238)U without samples and with Be samples with three thicknesses were measured in the double-bunch operation mode for a beam power of 100 kW.The Bayesian method was used to eliminate the influence of the double-bunch problem on neutron measurement in the energy region above 10 keV.The neutron total cross section of^(9)Be results was consistent with ENDF/B-VIII.0 evaluation library data in the 0.3 eV−20 MeV energy region.In the energy ranges of 0.3 eV to 10 keV and 0.01 to 20 MeV,the deviations between our results and the evaluation results of ENDF/B-VIII.0 were within 2.5%and 15%,respectively.In the resonance energy region,the measured resonance energies in our experiment were 0.63,0.82,and 2.8 MeV,respectively.The results showed that the total cross section uncertainties of three Be samples were within 2.2%in the energy region below 1 MeV.The total cross section uncertainty of 30 mm Be from ^(235)U was the smallest and less than 5%in the energy region of 0.3 eV−120 MeV.The results of this experiment can provide technical support for further data analysis and related nuclear data evaluation.展开更多
The Back-n white neutron source(known as Back-n)is based on back-streaming neutrons from the spallation target at the China Spallation Neutron Source(CSNS).With its excellent beam properties,e.g.,a neutron flux of app...The Back-n white neutron source(known as Back-n)is based on back-streaming neutrons from the spallation target at the China Spallation Neutron Source(CSNS).With its excellent beam properties,e.g.,a neutron flux of approximately 1.8×107 n/cm2/s at 55 m from the spallation target,energy range spanning from 0.5 eV to 200 MeV,and time-of-flight resolution of a few per thousand,along with the equipped physical spectrometers,Back-n is considered to be among the best facilities in the world for carrying out nuclear data measurements.Since its completion and commencement of operation in May 2018,five types of cross-section measurements concerning neutron capture cross-sections,fission cross-sections,total cross-sections,light charged particle emissions,in-beam gamma spectra,and more than forty nuclides have been measured.This article presents an overview of the experimental setup and result analysis on the neutron-induced cross-section measurements and gamma spectroscopy at Back-n in the initial years.展开更多
Purpose As a fourth-generation light source,High Energy Photon Source(HEPS)has much more stringent requirements to the beam orbit stability in both horizontal and vertical directions than the previous sources due to t...Purpose As a fourth-generation light source,High Energy Photon Source(HEPS)has much more stringent requirements to the beam orbit stability in both horizontal and vertical directions than the previous sources due to the much smaller beam sizes.Methods A Fast Orbit FeedBack(FOFB)system,with the closed-loop bandwidth around 500 Hz,is needed to meet the critical requirements.The latency of the FOFB system is the key to achieve these requirements.Results Proper design and implementation of the feedback logic to have low latency is illustrated in the paper.Calculation accuracy is kept in the whole operation except for the last-minute data translation into 32-bit floating point number.展开更多
Reprogrammable soft matter brings flexibility to soft robots so that they can display various motions,which is flourishing in soft robotics.However,the reprogramming of photoresponsive materials used in soft robots is...Reprogrammable soft matter brings flexibility to soft robots so that they can display various motions,which is flourishing in soft robotics.However,the reprogramming of photoresponsive materials used in soft robots is time-consuming using existing methods.In this study,we promote a strategy for rapid reprogramming via switchable photothermal conversion efficiency(PCE).The liquid crystalline elastomers doped with semiconductor bismuth compounds(Bi-LCE)used in this work exhibited large photothermal actuation with over 35%shrinkage in 5 s at high PCE state,which demonstrated little deformation at low PCE state.Furthermore,the material was capable of being reprogrammed up to 10 times,with only 20 min required for one PCE reversible switch.Based on this switchable PCE effect,the same Bi-LCE film displayed various shape changes through different programmable pattern.Additionally,a reprogrammable hollow tube made of PCE reprogrammable materials could tune the diameter,cross-section configuration,and surface morphology,which was crucial for microfluidics field.Reprogrammable materials provide endless possibilities for reusability and sustainability in robotics.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 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
The angle-differential cross sections of neutron-induced deuteron production from carbon were measured at six neutron energies from 25 to 52 MeV relative to those of n-p elastic scattering at the China Spallation Neut...The angle-differential cross sections of neutron-induced deuteron production from carbon were measured at six neutron energies from 25 to 52 MeV relative to those of n-p elastic scattering at the China Spallation Neutron Source(CSNS)Back-n white neutron source.By employing theΔE-E telescopes of the Light-charged Particle Detector Array(LPDA)system at 15.1°to 55.0°in the laboratory system,ratios of the angle-differential cross sections of the ^(12)C(n,xd)reactions to those of the n-p scattering were measured,and then,the angle-differential cross sections of the ^(12)C(n,xd)reactions were obtained using the angle-differential cross sections of the n-p elastic scattering from the JENDL-4.0/HE-2015 library as the standard.The obtained results are compared with data from previous measurements,all of which are based on mono-energic neutrons,the evaluated data from the JENDL-4.0/HE-2015 library and the ENDF-B/VIII.0 library,and those from theoretical calculations based on INCA code and Talys-1.9 code.Being the first white-neutron-source-based systematic measurement of the angle-differential cross sections of neutron-induced deuteron production reactions on carbon in several tens of MeV,the present work can provide a reference to the data library considering the lack of experimental data.展开更多
Purpose China spallation neutron source(CSNS)operates as a pulsed neutron source with a 25 Hz repetition rate.Precise data synchronization with the beam cycle is essential for analyzing abnormal beam status and diagno...Purpose China spallation neutron source(CSNS)operates as a pulsed neutron source with a 25 Hz repetition rate.Precise data synchronization with the beam cycle is essential for analyzing abnormal beam status and diagnosing faults at CSNS.This study aims to develop a beam-synchronized data acquisition system(BSDAQ)for the CSNS accelerator,which will be used to improve the understanding and optimization of accelerator performance.Methods To tackle the network bandwidth and data storage limitations caused by continuous full-cycle data storage,this paper introduces a BSDAQ(beamline scientific data acquisition system)that employs a time window,trigger-based data collection approach.The system can be operated in two modes:periodic trigger for regular data collection intervals and random trigger for event-driven scenarios,providing a flexible triggering mechanism for comprehensive data acquisition.Upon receiving a trigger,the system is designed to capture high-precision timestamped data segments from front-end device caches,align them precisely with the beam pulse cycle,and store the processed data in the database.Furthermore,the system provides the data access interface to facilitate subsequent offline analysis.Results and conclusion The prototype of the beam-synchronized BSDAQ has been implemented and tested at the CSNS accelerator.Some fast processes,such as intra-pulse beam chopping and the automatic recovery of the beam following the activation of the fast protection system,were documented and illustrated.These results are instrumental for refining beam control and improving the reliability of the accelerator's operation.展开更多
基金Project supported by the National Science Foundation of China (Grant Nos. 11653001 and 11653004)。
文摘Multiplexing technologies based on superconducting quantum interference devices(SQUIDs) are crucial to cryogenic readout of superconducting transition-edge sensor(TES) arrays. Demands for large-scale TES arrays promote the development of multiplexing technologies towards large multiplexing factors and low readout noise. The development of multiplexing technologies also facilitates new applications of TES arrays in a wide range of frequencies. Here we summarize different types of SQUID-based multiplexing technologies including time-division multiplexing, code-division multiplexing, frequency-division multiplexing and microwave SQUID multiplexing. The advances and parameter constraints of each multiplexing technology are also discussed.
基金partially supported by the National Natural Science Foundation of China(Grant No.60836001)the Key R&D Program of Guangdong Province(Grant No.2019B010143002)。
文摘Resonators in circuit quantum electrodynamics systems naturally carry multiple modes, which may have non-negligible influence on qubit parameters and device performance. While new theories and techniques are under investigation to deal with the multi-mode effects in circuit quantum electrodynamics systems, researchers have proposed novel engineering designs featuring multi-mode resonators to achieve enhanced functionalities of superconducting quantum processors. Here, we propose multi-mode bus coupling architecture, in which superconducting qubits are coupled to multiple bus resonators to gain larger coupling strength. Applications of multi-mode bus couplers can be helpful for improving i SWAP gate fidelity and gate speed beyond the limit of single-mode scenario. The proposed multi-mode bus coupling architecture is compatible with a scalable variation of the traditional bus coupling architecture. It opens up new possibilities for realization of scalable superconducting quantum computation with circuit quantum electrodynamics systems.
基金the National Natural Science Foundation of China(Grant Nos.11790321 and 11805282)the National Key R&D Program of China(Grant No.2016YFA0401601).
文摘Introduction The neutron capture cross sections are very important in the field of nuclear device design and basic physics research.Hydrogen-free liquid scintillator such as C_(6)D_(6)detectors are widely used in the neutron capture cross-sectional measurements for the low neutron sensitivity and fast time response.The Back-n white neutron source at China Spallation Neutron Source is the first spallation white neutron source in China,and it is suitable for neutron capture cross-sectional measurement.Materials and methods A C_(6)D_(6)detector system was built in the Back-n experimental station.The pulse height weighting technique was used to determine the system’s detection efficiency.The response to gamma rays of the C_(6)D_(6)detector was measured,and the energy resolution function was determined.Monte Carlo simulation with Geant4 code was carried out to get the weighting function of this C_(6)D_(6)detector system.Additionally,the systematic uncertainty of the weighting function was also determined.Conclusion According to the experimental and simulation results,this C_(6)D_(6)detector system can be used to measure neutron capture cross section.
文摘The China Spallation Neutron Source is an accelerator-based user facility for neutron,proton,muon applications and so on.The designed proton beam power is 100 kW for the first phase.Overall,the scope of accelerator control system covers four parts,the global systems,the device layer local controls and remote controls,the high-level applications and services and the integration of conventional facilities.The principle guideline is to adopt as many as possible matured technologies and commercial products in the design and implementation.The control system is based on Experimental Physics and Industrial Control System.VME64x bus is chosen for timing system and fast protection system.PLCs and embedded industrial computers are used in the device layer slow controls.Control System Studio is adopted as the high-level applications.Blade server-based virtualization platform is deployed for the computer system.The accelerator control system was completed in September 2017 and then transited to routine operations.The design,implementation and operation of the accelerator control system are described in this paper.
基金Supported by the National Natural Science Foundation of China(11790321,11805282)the National Key Research and Development Program of China(2016YFA0401601)。
文摘The capture cross sections of the ^(169)Tm(n,γ)reaction were measured at the back streaming white neutron beam line(Back-n)of the China Spallation Neutron Source(CSNS)using four C_(6)D_(6) liquid scintillation detectors.The background subtraction,normalization,and correction were carefully considered in the data analysis to obtain accurate cross sections.For the resonance at 3.9 eV,the R-matrix code SAMMY was used to determine the resonance parameters with the internal normalization method.The average capture cross sections of ^(169)Tm for energy between 30 and 300 keV were extracted relative to the ^(197)Au(n,γ)reaction.The measured cross sections of the ^(169)Tm(n,γ)reaction were reported in logarithmically equidistant energy bins with 20 bins per energy decade with a total uncertainty of 5.4%-7.0% in this study and described in terms of average resonance parameters using a Hauser-Feshbach calculation with fluctuations.The point-wise cross sections and the average resonance parameters showed fair agreement with the evaluated values of the ENDF/B-Ⅷ.0 library in the energy region studied.
基金Supported by National Key R&D Program of China(2016YFA0401604)National Natural Science Foundation of China(11775006)Science and Technology on Nuclear Data Laboratory and China Nuclear Data Center
文摘The^6 Li(n,t)~4 He reaction was measured as the first experiment involving neutron-induced charged particle emission reactions at the CSNS(China Spallation Neutron Source)Back-n white neutron source.The differential cross-sections of the^6 Li(n,t)~4 He reaction at 15 detection angles ranging from 19.2°to 160.8°are obtained from 1.0 eV to 3.0 MeV at 80 neutron energy points;for 50 energy points below 0.1 MeV they are reported for the first time.The results indicate that the anisotropy of the emitted tritium is noticeable above E_n=100 eV.The angle-integrated cross-sections are also obtained.The present differential cross-sections agree in general with the previous evaluations,but there are some differences in the details.More importantly,the present results indicate that the cross-sections of the^6 Li(n,t)~4 He reaction might be overestimated by most evaluations in the 0.5-3.0 MeV region,although they are recommended as standards below 1.0 MeV.
基金Supported by financially the National Key R&D Program of China(2016YFA0401604)the National Natural Science Foundation of China(11775006)
文摘Differential and angle-integrated cross sections for the 10B(n,α)^7 Li,10B(n,α0)^7 Li and 10B(n,α1)^7 Li^*reactions have been measured at CSNS Back-n white neutron source.Two enriched(90%)10B samples 5.0 cm in diameter and^85.0μg/cm^2 in thickness each with an aluminum backing were prepared,and back-to-back mounted at the sample holder.The charged particles were detected using the silicon-detector array of the Light-charged Particle Detector Array(LPDA)system.The neutron energy En was determined by TOF(time-of-flight)method,and the valid a events were extracted from the En-Amplitude two-dimensional spectrum.With 15 silicon detectors,the differential cross sections of a-particles were measured from 19.2°to 160.8°.Fitted with the Legendre polynomial series,the(n,a)cross sections were obtained through integration.The absolute cross sections were normalized using the standard cross sections of the 10B(n,α)^7 Li reaction in the 0.3-0.5 MeV neutron energy region.The measurement neutron energy range for the 10B(n,α)^7 Li reaction is 1.0 eV≤En<2.5 Me V(67 energy points),and that for the 10B(n,α0)^7 Li and10B(n,α1)^7 Li^*reactions is 1.0 eV≤En<1.0 MeV(59 energy points).The present results have been analyzed by the resonance reaction mechanism and the level structure of the 11B compound system,and compared with existing measurements and evaluations.
基金the China Spallation Neutron Source project—the National Science Foundation of China(Grant No.11575289)State Key Laboratory of Particle Detection and Electronics(Institute of High Energy Physics,CAS and University of Science and Technology of China)and Key Laboratory of Particle Acceleration Physics andTechnology(Institute of High Energy Physics,CAS).
文摘Purpose In order to increase CSNS beam power from 100 to 500 kW,the linac injection energy needs to be increased from 80 to 300 MeV.The combined layout of superconducting spoke cavities and elliptical cavities will be adopted to accelerate H−beam to 300 MeV.In this paper,a compact single spoke cavity withΦ50-mm beam aperture was proposed,with the RF performance of the spoke cavity optimized to Ep/Eacc<5,Bp/Eacc<9,as well as the good multipacting behavior.Methods CST Microwave Studio was used to optimize the RF performance(Epeak/Eacc,Bpeak/Eacc,R/Q)with cavity geometry parameters.After electromagnetic design was finished,multipacting behavior was studied with CST Particle Studio module,and cavity shape modification was made to get a reasonable<SEY>value.Results The simulation got optimum results of Epeak/Eacc=4.97 and Bpeak/Eacc=8.42 mT/(MV/m),and the<SEY>max is 1.52 at Eacc=7.74 MV/m.Conclusion A 648 MHzβg=0.4 single spoke cavity with beam apertureΦ50 mm was proposed in the paper.This compact cavity may be a very promising option for CSNS linac upgrading.In addition to the optimization of the RF parameters,the multipacting behavior of the cavity is also studied,and cavity shape is optimized to reduce<SEY>value.
基金Supported by the National Key Research and Development Plan(2016YFA0401603)the National Natural Science Foundation of China(11675155,11790321)Foundation of President of China Academy of Engineering Physics(YZJLX2016003)。
文摘The neutron total cross section data of^(9)Be are essential in the nuclear structure model research of light nuclei and nuclear power installations.The neutron total cross section of^(9)Be in the 0.3 eV−120 MeV energy region has been measured using time-of-flight and transmission methods with the Neutron Total Cross Sectional Spectrometer(NTOX)based on the multi-cell fast fission chamber at the China Spallation Neutron Source(CSNS)-Back-n white neutron source(Back-n).The fission count-neutron energy distributions of ^(235)U and ^(238)U without samples and with Be samples with three thicknesses were measured in the double-bunch operation mode for a beam power of 100 kW.The Bayesian method was used to eliminate the influence of the double-bunch problem on neutron measurement in the energy region above 10 keV.The neutron total cross section of^(9)Be results was consistent with ENDF/B-VIII.0 evaluation library data in the 0.3 eV−20 MeV energy region.In the energy ranges of 0.3 eV to 10 keV and 0.01 to 20 MeV,the deviations between our results and the evaluation results of ENDF/B-VIII.0 were within 2.5%and 15%,respectively.In the resonance energy region,the measured resonance energies in our experiment were 0.63,0.82,and 2.8 MeV,respectively.The results showed that the total cross section uncertainties of three Be samples were within 2.2%in the energy region below 1 MeV.The total cross section uncertainty of 30 mm Be from ^(235)U was the smallest and less than 5%in the energy region of 0.3 eV−120 MeV.The results of this experiment can provide technical support for further data analysis and related nuclear data evaluation.
基金Supported by the National Key Research and Development Plan(2016YFA0401600)the National Natural Science Foundation of China(11675155,11790321)。
文摘The Back-n white neutron source(known as Back-n)is based on back-streaming neutrons from the spallation target at the China Spallation Neutron Source(CSNS).With its excellent beam properties,e.g.,a neutron flux of approximately 1.8×107 n/cm2/s at 55 m from the spallation target,energy range spanning from 0.5 eV to 200 MeV,and time-of-flight resolution of a few per thousand,along with the equipped physical spectrometers,Back-n is considered to be among the best facilities in the world for carrying out nuclear data measurements.Since its completion and commencement of operation in May 2018,five types of cross-section measurements concerning neutron capture cross-sections,fission cross-sections,total cross-sections,light charged particle emissions,in-beam gamma spectra,and more than forty nuclides have been measured.This article presents an overview of the experimental setup and result analysis on the neutron-induced cross-section measurements and gamma spectroscopy at Back-n in the initial years.
基金This work is supported by Youth Innovation Promotion Association(Y9291420K2).
文摘Purpose As a fourth-generation light source,High Energy Photon Source(HEPS)has much more stringent requirements to the beam orbit stability in both horizontal and vertical directions than the previous sources due to the much smaller beam sizes.Methods A Fast Orbit FeedBack(FOFB)system,with the closed-loop bandwidth around 500 Hz,is needed to meet the critical requirements.The latency of the FOFB system is the key to achieve these requirements.Results Proper design and implementation of the feedback logic to have low latency is illustrated in the paper.Calculation accuracy is kept in the whole operation except for the last-minute data translation into 32-bit floating point number.
基金supported by the National Natural Science Foundation of China(62075064)the Key R&D Program of Guangzhou(202007020003)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(2021B1515020095,2021A1515110919)the Fundamental Research Funds for the Central Universities(2022ZYGXZR003).
文摘Reprogrammable soft matter brings flexibility to soft robots so that they can display various motions,which is flourishing in soft robotics.However,the reprogramming of photoresponsive materials used in soft robots is time-consuming using existing methods.In this study,we promote a strategy for rapid reprogramming via switchable photothermal conversion efficiency(PCE).The liquid crystalline elastomers doped with semiconductor bismuth compounds(Bi-LCE)used in this work exhibited large photothermal actuation with over 35%shrinkage in 5 s at high PCE state,which demonstrated little deformation at low PCE state.Furthermore,the material was capable of being reprogrammed up to 10 times,with only 20 min required for one PCE reversible switch.Based on this switchable PCE effect,the same Bi-LCE film displayed various shape changes through different programmable pattern.Additionally,a reprogrammable hollow tube made of PCE reprogrammable materials could tune the diameter,cross-section configuration,and surface morphology,which was crucial for microfluidics field.Reprogrammable materials provide endless possibilities for reusability and sustainability in robotics.
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.
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.
基金Supported by the National Natural Science Foundation of China(11775006)the National Key R&D Program of China(2016YFA0401604)。
文摘The angle-differential cross sections of neutron-induced deuteron production from carbon were measured at six neutron energies from 25 to 52 MeV relative to those of n-p elastic scattering at the China Spallation Neutron Source(CSNS)Back-n white neutron source.By employing theΔE-E telescopes of the Light-charged Particle Detector Array(LPDA)system at 15.1°to 55.0°in the laboratory system,ratios of the angle-differential cross sections of the ^(12)C(n,xd)reactions to those of the n-p scattering were measured,and then,the angle-differential cross sections of the ^(12)C(n,xd)reactions were obtained using the angle-differential cross sections of the n-p elastic scattering from the JENDL-4.0/HE-2015 library as the standard.The obtained results are compared with data from previous measurements,all of which are based on mono-energic neutrons,the evaluated data from the JENDL-4.0/HE-2015 library and the ENDF-B/VIII.0 library,and those from theoretical calculations based on INCA code and Talys-1.9 code.Being the first white-neutron-source-based systematic measurement of the angle-differential cross sections of neutron-induced deuteron production reactions on carbon in several tens of MeV,the present work can provide a reference to the data library considering the lack of experimental data.
基金funded by Youth Innovation Promotion Association of the Chinese Academy of Sciences,Y9291420K2,Yuliang Zhang。
文摘Purpose China spallation neutron source(CSNS)operates as a pulsed neutron source with a 25 Hz repetition rate.Precise data synchronization with the beam cycle is essential for analyzing abnormal beam status and diagnosing faults at CSNS.This study aims to develop a beam-synchronized data acquisition system(BSDAQ)for the CSNS accelerator,which will be used to improve the understanding and optimization of accelerator performance.Methods To tackle the network bandwidth and data storage limitations caused by continuous full-cycle data storage,this paper introduces a BSDAQ(beamline scientific data acquisition system)that employs a time window,trigger-based data collection approach.The system can be operated in two modes:periodic trigger for regular data collection intervals and random trigger for event-driven scenarios,providing a flexible triggering mechanism for comprehensive data acquisition.Upon receiving a trigger,the system is designed to capture high-precision timestamped data segments from front-end device caches,align them precisely with the beam pulse cycle,and store the processed data in the database.Furthermore,the system provides the data access interface to facilitate subsequent offline analysis.Results and conclusion The prototype of the beam-synchronized BSDAQ has been implemented and tested at the CSNS accelerator.Some fast processes,such as intra-pulse beam chopping and the automatic recovery of the beam following the activation of the fast protection system,were documented and illustrated.These results are instrumental for refining beam control and improving the reliability of the accelerator's operation.
