最新刊期
      卷 44 ， 期 1 ， 2021

        SYNCHROTRON RADIATION TECHNOLOGY AND APPLICATIONS

      • “在高能同步辐射光源项目中，通过多路激光干涉测量系统与磁铁预准直技术结合，实现了高精度磁铁定位，为实验工作提供解决方案。”
        ZHANG Zebin,MEN Lingling,XIN Hongbing,DONG Lan,LU Shang,LIANG Jing,LI Bo,WANG Xiaolong,LUO Tao,WANG Tong,MA Na,HE Zhenqiang,KE Zhiyong,HAN Yuanying,YAN Luping
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010101
        摘要：BackgroundThe main body of the high energy photon source (HEPS) storage ring contains 288 pre-collimating units. Due to the smaller size of the magnets in the cells, the positioning accuracy of magnets is required to be 3~5 times higher than that in previous projects.PurposeThis study aims to improve the accuracy of magnet pre-collimation and explore the high measurement accuracy and positioning accuracy of the unit magnet in the pre-collimation experiment.MethodsThe influence of multi-path laser layout schemes on the accuracy of magnetic pre-collimation was firstly simulated by combining the multichannel laser interferometry system with the magnet pre-collimation technology. Then, the simulation software MATLAB was used to optimize the layout scheme of "three high and one low" with the minimum standard deviation of the measured target point as the objective. Finally, four Leica AT960 laser trackers were employed for experimental verification of the measurement accuracy.ResultsThe results show that the standard deviation of the measured target point is less than 10 μm in the space range of 12.1 m×5.97 m×3 m, and the measurement accuracy is significantly improved compared with that of a single laser tracker.ConclusionsThe designed project meets the experimental working conditions and design requirements, it lays a foundation for subsequent beam center calibration and magnet calibration.  
        关键词：Multi-path laser;High precision;Magnet pre-alignment;Optimization;Layout   
        379
        |
        27
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973584 false
        发布时间：2024-10-25
      • “在小角散射实验站领域，专家开发了光路优化自动校准程序，提高了实验站的自动化程度。”
        HONG Chunxia,ZHOU Ping,HUA Wenqiang,YANG Chunming,BIAN Fenggang
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010102
        摘要：BackgroundThe quality of the experimental data is closely related to the optimal optical conditions of the end-station in the small-angle X-ray scattering (SAXS) beamline (lower scattering background, accurate beam intensity before and after the sample, etc.). At present, the optical conditions of the end-station are manually optimized in SAXS beamline (BL16B1) of shanghai synchrotron radiation facility (SSRF), which can not utilize the user's time effectively.PurposeThis study aims to design and implement an automatic calibration procedure with Python on the platform of EPICS (experimental physics and industrial control system) and CSS (control system studio).MethodsFirstly, the direct beam was searched and targeted using slit blades scanning, and then beam center was automatically optimized according to the single-objective and multi-objective optimization methods of genetic algorithm, the calibration is not completed until an optimal scattering background image is obtained.ResultsThe results show that the automatic beamline calibration system can complete the motors optimization of slits and beamstop in 30 min, much faster than manual operation.ConclusionsProposed automatic calibration system simplifies the optical path optimization of experimental station and improves the automation of the SAXS beamline station at SSRF.  
        关键词：Synchrotron radiation;EPICS;SAXS;Genetic algorithm;Automatic beamline alignment system   
        396
        |
        39
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973724 false
        发布时间：2024-10-25
      • “在纳米催化领域，科学家利用尿素沉积沉淀法合成了与FeOx形成界面作用的负载型Pt团簇，显著提升了CO催化氧化活性。”
        LIU Chengyong,HUANG Li,SONG Xueyang,HE Wenxue,WANG Siyu,LONG Zhixin,SUN Zhihu,WEI Shiqiang
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010103
        摘要：BackgroundMetal-oxide interface plays critical roles in promoting the catalytic activities of metal catalysts in a vast diversity of reactions. Maximizing this interfacial interaction so as to optimize the catalytic performance is an active subject of research that is worthy of intensive exploration.PurposeThis study aims to develop new Pt-group catalysts that are highly active towards cryogenic CO catalytic oxidation, and explore effective strategies to engineer metal-oxide (hydroxide) interfaces to weaken the adsorption of CO and to enhance the adsorption/activation of O2.MethodsSupported ultrasmall Pt nanoclusters (Ptnc-FeOx/SiO2) of (1.4±0.2) nm were synthesized using deposition-precipitation with urea (DPU). The catalytic performance towards CO oxidation was examined by using a fixed-bed U-shape flow quartz reactor. Extended X-ray absorption fine structure (EXAFS), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), transmission electron microscopy (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and energy-dispersive X-ray spectroscopy (EDX) techniques were combined to study the Ptnc-FeOx interfacial interaction.ResultsThe Ptnc-FeOx/SiO2 catalyst shows superior catalytic performance than Pt/SiO2 towards the CO oxidation reaction. Kinetics tests show that both the apparent activation energy and turnover frequency of Ptnc-FeOx/SiO2 are greatly enhanced as compared with Pt/SiO2 (19 kJ·mol-1 vs. 64 kJ·mol-1; 0.044 s-1 vs. 0.002 s-1 at 37 °C).ConclusionThe charge transfer from Fe to Pt results in the downshifted d-band center of Pt and reduces the CO adsorption strength, and hence, playing important roles in promoting the catalytic activity of Pt catalysts.  
        关键词：Metal-oxide interface;Ptnc-FeOx catalyst;CO catalytic oxidation;XAFS;DRIFTS   
        365
        |
        25
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973556 false
        发布时间：2024-10-25

        ACCELERATOR, RAY TECHNOLOGY AND APPLICATIONS

      • “上海软X射线自由电子激光低电平系统时钟本振设备设计，满足物理设计需求，达到国际先进水平。”
        XIAO Chengcheng,YIN Zhe,ZHANG Junqiang,GU Qiang
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010201
        摘要：BackgroundThe linear accelerator of Shanghai soft X-ray free-electron laser facility (SXFEL) operates at 5 712 MHz frequency. In the low level radio frequency (LLRF) system, C band microwave signals were down converted from the 5 686.556 MHz local oscillator (LO) signal to 26.444 MHz intermediate (IM) signal, and then quadruple frequency sampled by the 105.778 MHz clock signal. The stability of LO signal and clock signal can make great influence on the performance of the LLRF system.PurposeThis study aims to design and manufacture a local oscillator and clock device for satisfying the theoretical design requirements of the LLRF in SXFEL.MethodThe LO signal and clock signal were designed to be auto-correlated with the master oscillator signal. All the functional discrete device modules were installed in a shielded aluminum alloy shell, and were matched and interconnected by RF connectors after debugging and testing separately. The phase jitter integral of clock signal and LO signal, as well as the possible temperature sensitive nonlinear modules, i.e., temperature control of frequency divider and frequency multiplier, in clock Lo equipment were experimentally tested.ResultsThe experimental results show that the additional phase jitter integral of LO signal is 21.43 fs, better than the requirement of 40 fs.ConclusionsThe performance of this manufactured LO and clock device can meet the theoretical requirement of the SXFEL.  
        关键词：LLRF;C band;Local oscillator and clock;Phase jitter;Temperature control   
        404
        |
        39
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973401 false
        发布时间：2024-10-25
      • “随钻方位伽马测井技术取得新进展，专家设计实验装置，计算方位灵敏度，提高测量准确度。”
        YU Huawei,WANG Wending,ZHANG Li,XIAO Hongbing,YANG Quanjin,ZHANG Yuxin,YANG Zhengchun
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010202
        摘要：BackgroundThe response of azimuth gamma well logging in multiple sectors around the well cannot reflect the actual radioactive distribution of the formation.PurposeThis study aims to obtain the contribution factors of different sectors around the instrument on the detector.MethodsFirst of all, the influence of the formation around the well on the measurement results was verified through numerical simulation. Then an experimental device was designed and implemented for azimuthal sensitivity calibration, and an azimuthal sensitivity calculation method was derived by combining experimental data and numerical results.ResultsThe azimuthal gamma logging can obtain data that reflect the radioactive intensity distribution of the formation to a certain extent, but the calculated azimuth sensitivity factor can be used to accurately reflect the contribution of the 16 azimuth sectors around the well to the detector, and the intensity distribution contrast becomes better.ConclusionsThe radioactivity intensity of the formation calculated by the azimuthal sensitivity factor is closer to the real formation, hence effectively improves the measurement accuracy of azimuthal gamma logging, providing technical support for improving the measurement accuracy of azimuthal gamma logging and identifying formation boundary in the future.  
        关键词：Azimuth gamma logging;Azimuth sensitivity;Geosteering;Monte Carlo simulation   
        369
        |
        29
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973773 false
        发布时间：2024-10-25

        NUCLEAR ELECTRONICS AND INSTRUMENTATION

      • “在金属费米动量和费米能研究领域，基于连续硅酸钇镥晶体阵列探测器的一维湮没角关联测量方法，无需角度扫描即可实现高分辨和高效测量，极大缩短成谱时间。”
        LIU Jinyang,LIU Fuyan,KUANG Peng,ZHANG Huaiqiang,ZHANG Peng,YU Runsheng,CAO Xingzhong,WANG Baoyi
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010401
        摘要：BackgroundAngular correlation of annihilation radiation (ACAR) is a high-precision (sub-milliradian level) method for studying Fermi momentum and Fermi energy in metals. However, there are some disadvantages in traditional 1D-ACAR experimental device, such as complex device structure and long spectrum formation.PurposeThis study aims to propose a new 1D-ACAR measuring method with improved efficiency based on continuous LYSO crystal array detectors without angle scanning.MethodsContinuous LYSO crystal array and silicon photomultiplier (SiPM) array were used to form detector array, and the truncated center-of-gravity (TCOG) method was adopted as basic location algorithm. Based on the dependence of angular resolution of the array detector completely on its spatial resolution, Geant4 was employed to simulate the continuous crystal array detector (CCAD) to optimize detector structure and location algorithm. Both the array cell width and crystal size were optimized to increase the most possible resolution.ResultsSimulation results show that the angular resolution of the detector can be improved by forming photoelectric conversion array with suitable width of SiPM and increasing the size of continuous crystal. When the width of SiPM array unit is 1 mm and the crystal size is 30 mm (length)×35 mm (width), the angular resolution of CCAD is 0.84 mrad, reaching the angle resolution level of the 1D-ACAR experimental device. Angle resolution of CCAD can be further improved by increasing the crystal size.ConclusionsThe 1D-ACAR experimental device based on the CCAD can greatly shorten the long-time of spectrum formation without decreasing the angle resolution.  
        关键词：ACAR;Continuous crystal;Location algorithm;Position resolution   
        368
        |
        30
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973449 false
        发布时间：2024-10-25
      • “在数字化核仪器领域，尖峰脉冲成形算法引入平顶参数，与梯形脉冲成形方法对比，为高能量分辨率能谱获取提供新方案。”
        FAN Xinyang,WANG Min,HONG Xu,YANG Tibo,LIAO Guanghui,OUYANG Zhouxuan
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010402
        摘要：BackgroundDigital shaping algorithms are widely applied to improving the energy resolution of digital nuclear instruments.PurposeThis work aims to improve and analyze the performance of cusp-like shaping algorithm for digital nuclear signal with emphasis on the influence of shaping parameters on the shape of the shaped pulse.MethodsBased on the peak pulse forming algorithm, flat-top parameter was introduced into cusp-like pulse shaping algorithm. The fast silicon drift detector (FAST-SDD) detector produced by Amptek company was employed to measure the pulse signal obtained from manganese sample, the effect of shaping parameters on the shape of the output signal and the separation of pile-up pulses were investigated by the cusp-like pulse shaping method, and compared with the common trapezoidal pulse shaping methods. In addition, Cusp-like shaping and trapezoidal pulse shaping were used for the sampled nuclear pulse signals, and then amplitude discrimination was performed to obtain energy spectrum information. Finally, the influences of the two methods on the counting rate and energy resolution of the same time were studied.ResultsThe results show that the cusp-like pulse shaping has a fast falling edge and a narrow pulse width, makes it easier to separate the pile-up pulses than triangle pulse shaping.ConclusionsUnder the same peak time, trapezoidal pulse shaping has more advantages in energy resolution than cusp-like shaping, while cusp-like pulse shaping shows better performance in count rate.  
        关键词：Digital nuclear instrument;Cusp-like shaping;Energy resolution;Pile-up pulse   
        446
        |
        52
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973821 false
        发布时间：2024-10-25

        NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH

      • “在土壤侵蚀研究领域，137Cs示踪技术已广泛应用。专家分析了其主要问题和发展趋势，为建立高精度背景值预报模型和全球数据库提供解决方案。”
        WANG Yong,WU Zuo,SU Zheng'an,ZHOU Tao,WANG Junjie,LIU Yihan,WANG Xiaoyi
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010501
        摘要：As a new method of soil erosion research, 137Cs tracer technology has been widely used in soil erosion research due to its simplicity, rapidity and accurate. After the development of germination exploration, rapid development, popularization and application, the 137Cs technical system has become more mature. In order to understand and apply 137Cs trace technology more scientifically and lay a theoretical foundation for the application of 137Cs technology. The historical process of 137Cs tracer technology was reviewed using scientific bibliometrics. Meanwhile, the main problems existing in the current research were summarized, and the future development trend is prospected. At present, the research on the application of 137Cs to trace soil erosion mainly focuses on the determination of reference inventory, the construction and modification of 137Cs erosion model. It is necessary to establish a high-precision and high-resolution 137Cs reference inventory prediction model (suitable for different scenarios) and a global 137Cs reference inventory database. Due to the short half-life of 137Cs, the concentration of 137Cs is gradually decreasing, hence it is necessary to carry out the joint research of multi-nuclide tracing and multi-method in the future, and simultaneously revise the 137Cs erosion model to fit for estimation of soil erosion rate.  
        关键词：137Cs;Soil erosion;Reference inventory;137Cs erosion model   
        376
        |
        32
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973355 false
        发布时间：2024-10-25
      • “在正电子碰撞厚Ti靶的K壳层特征X射线产额研究中，通过实验测量与理论模拟值比较，发现实验值明显低于理论值，为后续研究提供参考。”
        TIAN Lixia,FANG Bingbing,HANG Zhongbin,CAO Xingzhong
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010502
        摘要：BackgroundX-ray emission from solid samples exposed to positron beams in the low-energy region is the basis of some material analysis techniques.PurposeThis study aims to measure the K-shell characteristic X-ray yields of Ti (Z=22) target collided by 10~30 keV positrons preliminarily.MethodsBased on the thick-target method, the Si-PIN detector with ultra-thin sensitive layer was adopted to detect the X-rays, and the positron intensity was determined through the 511 keV γ photon counts detected by the HPGe detector. The experimental data were compared with the PENELOPE simulations software which was based on the Distorted-Wave Born Approximation (DWBA) theory.ResultsThe results indicate that the shape of the characteristic X-ray yield curves is consistent in the considered energy regions, but the experimental data are obviously lower than those of the simulation, especially in the lower energy (≦15 keV).ConclusionsThe experimental method adopted in this paper is applicable, providing a reference for the future work.  
        关键词：Positron;X-ray yields;Thick-target;PENELOPE simulation   
        349
        |
        28
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973265 false
        发布时间：2024-10-25

        NUCLEAR ENERGY SCIENCE AND ENGINEERING

      • “在空间核动力领域，专家设计了小型氦氙冷却反应堆关键参数，通过编程建模和敏感性分析，确定了关键参数范围，为设计提供参考。”
        HU Wenzhen,DENG Jian,LIU Xiaojing,LI Zhongchun,XUE Bing
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010601
        摘要：BackgroundThe fast breeder reactor using helium-xenon mixture gas as coolant combined with Brayton thermoelectric conversion system is the development trend of space nuclear power in the future. In order to improve the system efficiency and reduce the system mass, many scholars have carried out research on the design of reactor parameters, but few of them involved helium xenon cooled reactors.PurposeThis study aims to design key parameters of small helium xenon cooled reactor.MethodsThe single channel model, primary surface regenerator and other component models were built by using FORTRAN 95 language programming, and the thermal system program was established afterward. The basic parameters of submerged subcritical reactor were used to verify the program, and the range of key parameters was determined by sensitivity analysis of a single parameter.ResultsThe results show that the regenerator has the greatest influence on the system efficiency and mass, and the pressure ratio of the compressor over 1.52 has less influence on the system mass.ConclusionsThis study provides a reference for the design of small helium xenon cooled reactor.  
        关键词：Helium-xenon cooled reactors;Thermal system;Key parameters   
        406
        |
        41
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973622 false
        发布时间：2024-10-25
      • “在射频负离子源领域，铯注入显著提升H-离子产额，为离子源性能优化提供新思路。”
        WANG Haoming,HU Chundong,CHEN Shiyong,XU Yongjian,PAN Junjun,WEI Jianglong,LIU Wei,CUI Qinglong,XIE Yahong,XIE Yuanlai,LIANG Lizhen
        Vol. 44, Issue 1, (2021) DOI: 10.11889/j.0253-3219.2021.hjs.44.010602
        摘要：BackgroundCesium injection can significantly reduce the work function of plasma grid surface of the radio frequency (RF) negative ion source, which is an effective way to promote the surface generation and improve the yield of H- ions.PurposeThis study aims to find the impact of the temperature of plasma grid (PG) and the cesium injection velocity on the yield of H- ions under the condition of cesium injection.MethodsBased on the experimental platform of high power radio frequency negative ion source, the mechanism of H- ions surface generation and cesium injection were the theoretical basis, the current of H- ions, electron current and the relative strength of cesium characteristic spectral line were taken as numerical benchmarks. The effects of PG plate temperature and cesium injection rate on the yield of RF negative H- ion source were investigated by emperiments.Results & ConclusionsUnder current experimental conditions, cesium injection has the best effect when the PG temperature is in the range of 180~200 ℃. The H- ions conversion rate reaches dynamic equilibrium after about 162 min when the temperature of cesium injection is 250 ℃/270 ℃.  
        关键词：Radio frequency negative ion source;Surface generation;Cesium injection;Thermostatic control   
        350
        |
        26
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 5973671 false
        发布时间：2024-10-25
      0