最新刊期
      卷 0 ， 期 0 ， 2020
      • ZHONG Yi,ZHANG Wei,ZHANG Jidong,WANG Shuhua,HE Yongzhou,ZHOU Qiaogen
        Vol. 37, Issue 4, Article number: 040101(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040101
        摘要：Background: The cryogenic calibration system of Hall probe is an important tool for high precision magnetic measurement at low temperature. Purpose: In order to setup the calibration system, simulations are performed to study the temperature distribution and thermal deformation of the conduction components which have a direct impact on the Hall probe calibration. Methods: Finite element method was used to the steady thermal analysis and cold deformation analysis. Joule effect of the Hall sensor at low temperature was simulated, and temperature differences from the Joule effect were then figured out. Results: When the temperature of the secondary cold head is 4.42 K, the simulated temperature of the Hall probe is 6.75 K, and the simulation result of Hall probe axial deformation is 1.11 mm. Experimental result of the temperature of hall probe is 6.44 K. Conclusion: The simulation result is reliable and can provide the basis for Hall probe temperature correction.Cited  
        关键词：Hall probe;Cryogenic calibration;Joule effect;Finite element analyses method   
        16
        |
        10
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116675 false
        发布时间：2021-03-03
      • TONG Jin,GU Ming,YUAN Qibing,LIU Yongfang
        Vol. 37, Issue 4, Article number: 040102(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040102
        摘要：Background: Proton has a higher precision in cancer treatment than traditional X or γ radiation because of its Bragg peak feature. Shanghai Institute of Applied Physics is participating in the development of the first proton therapy facility of China. Purpose: Stable and adjustable proton beam extraction is one of the key points of the project. The aim of this work is to design high resolution frequency signal source for slow beam extraction. Methods: A fully digital signal source platform is implemented using FPGA developing board DE2-115 and Direct Digital Synthesizer (DDS) board AD9910/PCBZ. The communication between DE2-115 and AD9910/PCBZ is realized via SPI interface with Verilog HDL programming. Results: High accuracy and flexible frequency signal is obtained through the platform and visualized clearly by oscilloscope and spectrometer, despite a little harmonic. Conclusion: The preliminary results show that scheme design of the project is reasonable and meets the needs of demands although many aspects of the scheme have to be improved further.Cited  
          
        12
        |
        8
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116662 false
        发布时间：2021-03-03
      • ZHONG Shaopeng,ZHAO Minghua,ZHANG Junqiang
        Vol. 37, Issue 4, Article number: 040103(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040103
        摘要：Background: Low-energy electrons linear accelerator with magnetron as power source has been more widely used in medical, radiation, X-ray detection and other fields. Purpose: The aim is to control magnet’s operating frequency in an industry accelerator. Methods: A set of automatic frequency control (AFC) system is developed by using digital I/Q technology combined with Field-Programmable Gate Array (FPGA). Microwave signal generated by the magnetron tube accelerates the electron beam in accelerator, the magnetron frequency stability is important for beam energy, energy spread and emittance. But magnetron is an oscillator with its frequency affected by temperature, vibration, load-pull effect, which will produce frequency drift, the AFC system, which includes travelling wave phase control and dual-cavity frequency discriminator, can stabilize frequency accurately. Results: Experimental results show that the frequency drift could be detected through phase discrimination and then be used for feedback control to achieve effective magnetron frequency control. In machine commissioning frequency drift is controlled within 1 kHz, to meet the requirement of less than 500 kHz. Conclusion: The theory and engineering design of digital I/Q technology proposed in the paper provide a feasible and achievable solution in the magnetron frequency control.Cited  
          
        15
        |
        10
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116650 false
        发布时间：2021-03-03
      • CHEN Xi,WANG Jigang,XUAN Ke,LI Chuan,WEN Pengquan,JIANG Siyuan,LIU Gongfa
        Vol. 37, Issue 4, Article number: 040104(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040104
        摘要：Background: The Hefei Light Source (HLS) is a VUV and soft X-ray synchrotron radiation source. An upgrade project was started at the end of 2009 to improve the performance of the light source. The cooling water monitor system is a part of this upgrade project. Purpose: This system is developed under EPICS environment to monitor 596 distributed signals of the cooling water system, including the water temperature, pressure and flow, magnet temperature, and environment temperature in the tunnel. Methods: The cRIO-9073 controller from National Instruments (NI) is used as the hardware platform. The software development is implemented using LabVIEW with the EPICS interface “EPICS Server IO Server” from NI. A file with the hardware information, such as chassis serial number, model serial number, etc., is used by the software to configure the installed hardware. A self-check program is developed to check whether the software matches with the hardware via the configuration file. System mirror-image method is used for the software installation to effectively speed up the installation process. Results: The test results in the commissioning indicate that this system is reliable, flexible, and easy to operate. Conclusion: NI cRIO with LabVIEW can be used to effectively monitor a large number of distributed signals, and can be easily integrated into EPICS based control systems.Cited  
        关键词：Cooling water system;EPICS;cRIO;LabVIEW   
        13
        |
        9
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116636 false
        发布时间：2021-03-03
      • DU Long,CHANG Le,WANG Yuting,ZHANG Song,CAO Xiguang,WANG Hongwei,ZHANG Guoqiang,ZHONG Chen,LI Chen
        Vol. 37, Issue 4, Article number: 040201(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040201
        摘要：Background: Being of very high detection efficiency and small size, Lithium iodide (LiI) scintillator detector is used extensively in neutron measurement and environmental monitoring. Purpose: Using thermal reactor, neutron detectors will be tested and calibrated. And a new neutron detector device will be designed and studied. Methods: The relationship between the size and detection efficiency of the thermal neutron detector 6LiI/natLiI was studied using Monte Carlo code GEANT4 and MCNP5 package, and the thermal neutron efficiency of detector was calibrated by reactor neutrons. Results: The theoretical simulation shows that the thermal neutron detection efficiency of detector of 10-mm thickness is relatively high, the enriched 6LiI is up to 98% and the nature natLiI 65%. The thermal neutron efficiency of detector is calibrated by reactor thermal neutrons. Considering the neutron scattering by the lead brick, high density polythene and environment neutron contribution, the detection efficiency of 6LiI detector is about 90% and natLiI detector 70%. Conclusion: The detector efficiency can reach the efficiency value of theoretical calculations.Cited  
        关键词：Monte Carlo;Scintillation detector;Thermal reactor;Efficiency   
        24
        |
        13
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116616 false
        发布时间：2021-03-03
      • ZHANG Wenyi,LIU Zhongchao,RUAN Shuzhou,FAN Saijun,JIAO Ling
        Vol. 37, Issue 4, Article number: 040202(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040202
        摘要：Background: Iodine-125 seeds brachytherapy is a cancer treatment method with seeds implanted in tumor tissue. Before clinic application, experiments should be done to determine the dosimetric parameters of seed due to their influences on treatment effects. In this paper, using thermoluminescent dosimeters (TLD) method, axial and radial dose distribution of Iodine-125 seed are measured and analyzed in the lumen tissue model. Purpose: The aim is to investigate the radial and axial dosimetric properties of I-125 seed, and provide scientific data for cavity cancers treatments with seeds brachtherapy. Methods: LiF (Mg, Cu, P) TL flake, grain and glass dosimeters were used for analog measurements of dose distribution inside the cavity phantom. Three kinds of TLD were measured by FJ-427A1 spectrometer after irradiation. Results: The radial dose distribution at different directions was anisotropic, and the variance of axial dose distribution was more than 10%. These results indicated that the iodide rod inside the titanium tube might deviate from the center of the axial. Conclusion: It is necessary to study the influences of seeds dosimetric parameters and arrangements on possible brachytherapy effects.Cited  
          
        13
        |
        9
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116602 false
        发布时间：2021-03-03
      • ZUO Zhenzhong,WU Zhendong,QU Guopu,LIANG Haiying,JU Wei,CHEN Dongfeng,FU Yuanyong
        Vol. 37, Issue 4, Article number: 040203(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040203
        摘要：Background: The nuclear pore membrane is a kind of liquid filtration material manufactured by irradiation and chemical etching. Various conditions in etch process have a great influence on etch rate. Purpose: The influence factors of concentration and temperature of etch solution and the irradiation energy of heavy ions on etch rate was studied. Methods: Four layers of PET (polyethylene terephthalate) films were stacked together and were irradiated with 140-MeV 32S ions at room temperature under vacuum conditions. Utilizing conductivity measurement technique, the electrical current changes through the irradiated PET film were monitored during etching, from which the breakthrough time and therefore the track etching rate was calculated. Results: The results show that there is an exponential correlation between etch rate and temperature, and a linear correlation between etch rate and concentration. The track etching rate increases linearly with energy loss rate. Empirical formula for the bulk etching rate as a function of etchant concentration and temperature was also established via fitting of measurements. Conclusion: It is concluded that by using 1.6-MeV?u?1 32S ions, PET nuclear pore membrane with cylindrical pore shape can be prepared at 85 °C with etchant concentration of 1mol?L?1.Cited  
        关键词：Nuclear pore membrane;Conductivity method;Track-etch rate;Bulk-etch rate;Energy loss rate   
        15
        |
        11
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116586 false
        发布时间：2021-03-03
      • SHANG Jianbo,SHI Quanlin,WANG Qunshu,BAI Tao,LIU Jie,DAI Yihua,LI Mou,ZHONG Zhenyuan
        Vol. 37, Issue 4, Article number: 040204(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040204
        摘要：Background: Activity-size distribution of fallout particles plays an important role in fallout prediction project. It also suggests how radioactive nuclides attached by carriers such as soil particles or debris and helps us know why fractionation happens. It should be determined by sampling, measurement and analysis, but not all this work well done in each ground explosion. Purpose: Feasibility of work to calculate the lower limit of particle size with special cumulate activity fraction by off-site contours of residual gamma radiation and dynamic model that can trace fallout particles was examined. Methods: Off-site contours of residual gamma radiation from Small Boy test were digitized, and the cumulative activity fraction in each area was estimated. Based on the spatial distribution of particles of different sizes deposited on the ground surface, which is calculated with a dynamic fallout prediction code, the lower limit of particle size with special cumulate activity fraction was discovered. Results: The results show that cumulative activity contribution from particles with diameter of a few hundred micrometer was 14% less than obtained with Bridgeman Equation. Conclusion: It’s feasible to calculate cumulative activity-size distribution of fallout particles from off-site contours of residual gamma radiation, and this work can help us to know activity-size distribution in different ground nuclear explosions.Cited  
        关键词：Fallout;Radiation field;Cumulative activity-size distribution   
        14
        |
        10
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116571 false
        发布时间：2021-03-03
      • WEI Xing,WANG Feng,WANG Ying,XIAO Wuyun,AI Xianyun,ZHANG Bin,XU Hongxuan,ZHANG Lei,MA Xinhua
        Vol. 37, Issue 4, Article number: 040401(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040401
        摘要：Background: In nuclear monitoring applications, a gamma-ray imager based on coded aperture (CA) technology can get a 2-D source intensity distribution map, which is superimposed on a corresponding video camera image, to visualize an object scene indicating the location, activity and even the type of radionuclide of radioactive sources. Though the CA imager has some advantages, it is still limited to imaging sources at large standoff distance or with high energy photon emission. There are two main barriers. One is that increasing the area of position-sensitive detector brings unacceptable additional system complexity and cost. Another is that thicker detector induces image blurring. Purpose: In order to overcome the disadvantages of CA imager, a novel gamma-ray imager prototype based on rotating modulator (RM) technique is built in our laboratory. Methods: The laboratory prototype consists of a rotating collimator, a NaI(Tl) detectors array, readout and control circuit, a stepping motor, and their supporting frame. Experimental tests were carried out. Results: The field of view (FOV) of this prototype is ±14.6?. An angular resolution of 2? is achieved. The energy resolution of the NaI(Tl) detectors is 7%@662 keV and their average detection efficiency to 662-keV gamma-rays is 22.2%. Conclusion: A RM imager is capable of imaging gamma-rays and measuring the incident photon spectrum simultaneously. Thus it can form radioactive map of different radionuclide. Through temporal modulation and image reconstruction, the angular resolution of RM imager is comparable to that of a CA imager. Using non-position-sensitive detectors, the detector area and thickness can be increased to improve the detection efficiency with relatively low cost. The study is still in progress and the performance of the RM imager is expected to be improved for further development.Cited  
        关键词：Rotating modulator;γ-ray imaging;Image reconstruction;Detection efficiency   
        13
        |
        10
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116555 false
        发布时间：2021-03-03
      • HUANG Can,YANG Kang,MA Mingwang,HAI Yang,ZHANG Zengyan,ZHAO Hongwei,ZHU Zhiyong
        Vol. 37, Issue 4, Article number: 040501(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040501
        摘要：Background: As the core component of terahertz system, terahertz source determines the performance of the whole system. The THz wave emission efficiency depends decisively on the THz emitting materials which are usually made of low-temperature-grown gallium arsenide. It is found that through ion irradiation better THz wave emission material can be prepared, which overcomes the poor reproducibility of high quality material prepared by the traditional method. Purpose: In order to find out the best irradiation condition for producing the required photoconductive material, we try to clarify the mechanism of the THz wave emission induced by ion implantation. Methods: Applying Monte Carlo method, we simulated the terahertz emission under different defect conditions, and tested the emission efficiency of GaAs and InP(Fe) irradiated by N ions with the energy of 500 keV and 1.5 MeV, respectively. Results: MC simulation study shows that both capture cross-section and trap density can cause changes in terahertz pulse width and peak intensity. From the experiments conducted on ion irradiated semiconductors we found only the peak intensity changes with the irradiation fluence. Conclusion: It is proposed that intrinsic defects introduced during growth of crystals are the key defects that contribute mainly to the terahertz wave emission behavior, and defects introduced by ion irradiation may only modify the transport property of carriers through scattering in semiconductor, by which it changes the terahertz wave emission performance.Cited  
        关键词：Monte Carlo simulation;Terahertz emission crystal;Ion irradiation induced defects   
        12
        |
        9
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116539 false
        发布时间：2021-03-03
      • HE Linfeng,HAN Songbai,WANG Yu,WEI Guohai,WU Meimei,WANG Hongli,LIU Yuntao,CHEN Dongfeng
        Vol. 37, Issue 4, Article number: 040502(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040502
        摘要：Background: Spatial resolution is the key parameter for neutron radiography facility. A model of the integrated system resolution is important when designing or using a system to ensure that the realistic resolution goals can be established and achieved. Purpose: For this resolution modeling analysis we focused on the effects of the geometry effects of L/D, the optical diffusion response of the scintillator and the sampling at the sensor (CCD or CMOS camera) and a formula was derived indicating their functional relationship. Methods: This resolution modeling analysis has been down by theoretic calculations. Then this integrated system resolution model was used as an empirical methodology to verify and optimize the performance of the detection system for real-time neutron radiography at China Advance Research Reactor. Results: The special resolutions at very collimation conditions have been calculation by using this method. And three of important parameters of this resolution model have been discussed to optimize the system performance. Conclusion: These resolution analysis concepts and methods will benefit both the design and the characterization of radiography systems.Cited  
        关键词：Neutron radiography;Spatial resolution;Modulation transfer function   
        22
        |
        10
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116524 false
        发布时间：2021-03-03
      • JI Zhilong,MA Yuanwei,WANG Dezhong
        Vol. 37, Issue 4, Article number: 040503(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040503
        摘要：Background: In radioactive nuclides atmospheric diffusion models, the empirical dispersion coefficients were deduced under certain experiment conditions, whose difference with nuclear accident conditions is a source of deviation. A better estimation of the radioactive nuclide’s actual dispersion process could be done by correcting dispersion coefficients with observation data, and Genetic Algorithm (GA) is an appropriate method for this correction procedure. Purpose: This study is to analyze the fitness functions’ influence on the correction procedure and the forecast ability of diffusion model. Methods: GA, coupled with Lagrange dispersion model, was used in a numerical simulation to compare 4 fitness functions’ impact on the correction result. Results: In the numerical simulation, the fitness function with observation deviation taken into consideration stands out when significant deviation exists in the observed data. After performing the correction procedure on the Kincaid experiment data, a significant boost was observed in the diffusion model’s forecast ability. Conclusion: As the result shows, in order to improve dispersion models’ forecast ability using GA, observation data should be given different weight in the fitness function corresponding to their error.Cited  
          
        18
        |
        11
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116512 false
        发布时间：2021-03-03
      • CHEN Haiying,QIAO Yahua,WANG Shaowei,CHEN Yan,LAN Bing,ZHANG Chunming
        Vol. 37, Issue 4, Article number: 040601(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040601
        摘要：Background: When fission occurs in fuel of reactor core, it produces a large amount of radioactive materials, which may cause harm to the environment and human health. Purpose: The radioactive materials in fuel could provide input data for shielding design of reactor coolant radioactive source term, analysis of accident source term and radioactive consequence assessment. Methods: The calculation of radioactive source in fuel was studied for pressurized water reactor, the calculation methods and models were established using ORIGEN-S, and the difference of nuclides radioactivity under different burnup was also studied. The effect of different versions of ENDF/B cross-section database on the calculation results was analyzed, so as to provide a basis for the calculation of radioactive source in fuel. Results: The results showed that the method established by ORIGEN-ARP was more suitable for calculating radioactive source term in fuel assemblies and the different versions of ENDF/B database had a great impact on radioactivity calculation. Conclusion: Based on the ENDF/B-VII database, using ORIGEN-ARP to calculate radioactive source term in fuel assemblies could not only improve efficiency, but also improve the calculation accuracy.Cited  
        关键词：Fuel assembly;ORIGEN-S;ENDF/B;Source term   
        16
        |
        12
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116498 false
        发布时间：2021-03-03
      • GUO Xueqing,SUN Zhongning,WANG Jianjun
        Vol. 37, Issue 4, Article number: 040602(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040602
        摘要：Background: The open natural circulation system has been used gradually in the passive safety system after severe accidents such as passive containment cooling system. Purpose: The aim is to investigate the start-up process of the open natural circulation system, and analyze the experimental phenomena and flow characteristics under different heating power and inlet subcooling conditions in detail. Finally, the map of the instability boundary during the startup of the natural circulation system is given. Methods: Experimental facility was set up and numbers of experiments under different conditions were conducted. The flow characteristics and mechanisms with different flow phenomena are analyzed in detail combining with the measurement results of the fluid temperature, pressure and mass flow rate. Finally, all the flow behaviors were classified under different conditions. Results: The results are as follows: the system which operates under low-power conditions will experience the stable single-phase, two-phase oscillation and stable two-phase flow sequentially with the inlet subcooling increasing. During the two-phase oscillation phase, two flow modes including the flashing-induced instability and the combination of the boiling eruption and flashing-induced instability occur. Conclusion: The instability region of the system enlarges with the increase of the heating power, which even makes it difficult to form the stable two-phase flow. During the two-phase oscillation phase, both the flashing-induced instability and the combination of the boiling eruption with flashing-induced instability belong to the density wave instability.Cited  
        关键词：Open natural circulation;Startup;Flashing;Boiling eruption;Density wave instability   
        15
        |
        9
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116487 false
        发布时间：2021-03-03
      • CAI Baowei,WANG Jianjun,SUN Licheng,ZHANG Nana,YAN Changqi
        Vol. 37, Issue 4, Article number: 040603(2014) DOI: 10.11889/j.0253-3219.2014.hjs.37.040603
        摘要：Background: The flow field in the vane-type bubble separator in the gas removal system developed for Molten Salt Reactor (MSR) was obtained by the Computational Fluid Dynamics (CFD) software of Fluent. Purpose: On the basis of the single phase water simulation, analysis was also conducted on the principle of the bubble separator as well as the factors affecting its performance. Methods: Firstly, different turbulence models were compared against the experimental data, among which the Reynolds Stress Model gave the best results under different working conditions. Then, by using of this model, further researches on the flow field in vane separator were carried out. Results: It is indicated that the water flow with low velocity and low pressure forms rapidly in the central area after flowing through the swirl vanes of the separator at the volume flow of 20 m3?h?1, and a high radial pressure gradient appears near the center of the cross section. Conclusion: As a result, if there are some bubbles in the flow, they will be pushed to the center of the separator and merge to form a steady air core due to the large radial pressure gradient, leading to the continuous separation of bubbles from the water flow.Cited  
          
        11
        |
        9
        |
        0
        <HTML>
        <L-PDF><Meta-XML>
        <引用本文> <批量引用> 7116473 false
        发布时间：2021-03-03
      0