最新刊期
      卷 38 ， 期 10 ， 2015
      • GENG Helong,LENG Yongbin,ZHOU Weimin,LAI Longwei,SHEN Tong,YAN Yingbing
        Vol. 38, Issue 10, Article number: 100101(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100101
        摘要：Background: Required by machine malfunction analysis, the beam orbit interlock system for the storage ring needs to be upgraded at the Shanghai Synchrotron Radiation Facility (SSRF). Purpose: This study aims to implement an upgraded new interlock system that can label 140 interlock signals coming from different Beam Position Monitor (BPM) electronics and record all data in the new system. And the turn-by-turn data in the BPM electronics Post Mortem buffer will be latched whenever the interlock occurs. Methods: The interlock signals and the latch signals were transmitted through the optical fiber and processed in an NI PXI 7813R Field Programmable Gate Array (FPGA) board. NI PXI-8106 controller is configured to run Linux operation system for Input/Output Controller (IOC) of Experimental Physics and Industrial Control System (EPICS) and communicate with PXI 7813R board which processes all interlock signals. Results: All interlock signal processing and latched trigger signal output were achieved in the FPGA board. The new system was fully integrated to the main EPICS for the storage ring. And the system runs as expected. Conclusions: The online test data show that the new system can detect the first interlock signal caused by the machine abnormality while the turn-by-turn data are latched. The analysis of turn-by-turn data shows the first BPM electronics which sends the interlock signal. The result is consistent with the FPGA board. Meanwhile, beam orbit changes were observed during beam abortions. Abstract  
        关键词：SSRF;Beam diagnostics system;Beam orbit interlock;FPGA   
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        发布时间：2021-03-03
      • WEN Pengquan,SONG Yifan,LI Bing,XUAN Ke,LIU Gongfa
        Vol. 38, Issue 10, Article number: 100102(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100102
        摘要：Background: A system based on relation database has been developed to archive history data in the Hefei Light Source II (HLS-II), which provides a foundation for analysis of the beam cleaning. Purpose: The beam cleaning analysis is to give an assessment on vacuum system and storage ring operation status. Methods: A method based on mathematical statistics is described. Lifetime data and pressure data are selected from the relation database for the beam cleaning analysis. A data processing program is designed by MATLAB. The data for the beam cleaning since HLS-II commissioning in 2014 are acquired by the program. Due to ceramic vacuum chamber of HLS-II was replaced in Nov. 2015, the process of the beam cleaning analysis is divided into two stages. Results: The results show that the dynamic vacuum pressure can meet design requirement when integrated current reaches 80 A?h. The effect of the beam cleaning in second stage is better than that in the first stage. Conclusion: The method presented in this paper is convenient and efficient. The data processing program is beneficial to researchers to evaluate beam cleaning status in storage ring quickly. Abstract  
        关键词：HLS-II;Beam cleaning;Lifetime;Vacuum pressure   
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        发布时间：2021-03-03
      • HE Jun,ZHAO Xiaoyan,WANG Lin,DU Yaoyao,ZHAO Ying,SUI Yanfeng,YUE Junhui,CAO Jianshe
        Vol. 38, Issue 10, Article number: 100103(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100103
        摘要：Background: A beam loss system that uses the PIN diode as the detector has been set up on Beijing Electron–Positron Collider II (BEPCII) storage after 8-a routine operation. Further study and analysis should been carried out based on the historical data. Purpose: This study aims to learn the beam loss process in depth and further optimize the parameters of the accelerator. Methods: Based on the machine size and beam parameter of BEPCII, the Monte Carlo simulation of the cluster electrons in the storage ring was performed to provide reference for installation position of the beam loss system. Then different methods, including adding all the beam loss monitor (BLM) counts, adding the inner detector, adding the outer detector, have been used for data analysis of the beam life time, beam loss distribution, beam envelope and dispersion, etc., under both the collider mode and synchrotron mode. Results: The results show that the BLM system is useful to study the beam life time and diagnose the beam loss processes. The beam loss system for BEPCII works stablely. The detector counts are much smaller than the dynamic range of the detector. Conclusion: Over the eight years, the response of the beam loss system does not change a lot, which implies that the radiation tolerance of beam loss system is very good. Lower than expected detector counts show that the detectors position needs to be optimized, the sensitivity is not enough. The beam loss system is an effective method to study the “dust” effect. Abstract  
        关键词：Diode;Beam loss;Storage ring;Beam life time   
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        发布时间：2021-03-03
      • LI Tao,ZHANG Bin,LIU Lubei,HE Yuan,ZHANG Shenghu
        Vol. 38, Issue 10, Article number: 100201(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100201
        摘要：Background: 162.5 MHz (?=0.10) Half Wave Resonance (HWR) superconducting cavity is used for the low-energy section of injection II in the China Initiative Accelerator Driven System (CIADS) project. Purpose: The helium pneumatic tuner is designed on the tuning range and performance requirements of the mentioned cavity above. There is no domestic reference. Methods: In order to make sure that it would run well, room temperature test was made. Results: In the test of copper modal cavity, the tuning range reached 640 kHz, which satisfied the tuning range requirements. In the test of Niobium cavity, the connection of the frequency with the gas pressure was satisfied, the tuning sensitivity was 0.272 kHz?hPa?1. Gas mass flow control scheme was put forward. And a pneumatic platform for resolution test was set up. In the test, the tuner met the requirement of the tuning resolution, of which the resolution precision reached 4.4–15 Hz. The heat transfer between superconducting cavity and the tuner was calculated, and its value was no more than 0.002 W, which was lower than the thermal radiation between the cryostat and the tuner. Conclusion: The tuner could be used for HWR cavity. Abstract  
        关键词：Helium pneumatic;Tuning;Superconducting cavity;Control of gas mass flow   
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        发布时间：2021-03-03
      • HAN Junjie,ZHU Jinhan,ZHANG Bailin,CHEN Lixin,LIU Xiaowei
        Vol. 38, Issue 10, Article number: 100202(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100202
        摘要：Background: It is well known that the main components of clinical linac such as the primary collimator, flattening filter and secondary collimator affect the X-ray energy spectra. How does it appear is the foundation of dose calculation, and it is helpful for building up a beam model. Purpose: This paper aims to make a detailed study on the effects of these main components on the X-ray energy spectra of a clinical linac beam. Methods: Monte Carlo program EGSnrc/BEAMnrc is employed to build up the beam model of Varian 600C linac, as well as the other three different beam models: without primary collimator, without flattening filter, without secondary collimator at the same time. After respective simulations, we use Beamdp program to analyze the phase space files, so as to obtain energy spectra for different models. Results: Flattening filter has heavy influence on X-ray beam’s energy spectra, the mean energy increases by 48.9% compared with its absence. But the primary collimator and secondary collimator have little influence on energy spectra, the change of mean energy is within 1% compared their absence. In the center field size of 10 cm×10 cm, flattening filter could let the energy fluence decrease by 52.4%, but the distribution becomes more flat and the unflatness changes from 15.09% to 1.82%; primary collimator could increase energy fluence by 1.58%; but secondary collimator could decrease the energy fluence by 2.00%. Conclusion: Flattening filter has mainly influence on the energy spectra of X-ray beam, it could let the mean energy increase and the energy fluence distribution become more flat; the scatter of primary collimator for X-ray beam must be taken into account whilst the scatter of secondary collimator for X-ray beam can be neglected. The results are meaningful to build a X-ray beam model for clinical linac. Abstract  
        关键词：Primary collimator;Flattening filter;Secondary collimator;X-ray energy spectrum   
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        发布时间：2021-03-03
      • XIONG Qili,SHI Yong,XU Gang,GU Qiang
        Vol. 38, Issue 10, Article number: 100203(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100203
        摘要：Background: The dose distribution of the Flatting-Filter-Free (FFF) of medical linear accelerator (LINACS) has been proved to have its advantages in clinical use. With the recent development of three-dimensional conformal radiotherapy and intensity-modulated radiation therapy, field of clinical treatment is mainly achieved by using Multi-leaf Collimator (MLC). Because of the rare researches on dosimetry characteristics of MLC field under FFF beam, it is interesting to note the importance of its further development. Purpose: For the TureBeam accelerator of 6 MV-X, the dose characteristics of the MLC are studied in the presence of the FFF beam. Methods: The off-axis dose curve characteristics are analyzed by using the Monte Carlo (MC) method, combined with three-dimensional dose scanning data. Results: The compared results, including MLC leaf position accuracy, leakage radiations along X-axis and Y-axis, field penumbra and the influence of the concave-convex structure of the leaf, show that the MC simulations result in good agreement with the clinical data. MLC irregular radiation field’s geometry, MC calculation and clinical measurement discrepancy degree are 3.6290%, 3.2626% and 2.0394%, respectively. A circle field of radius 5 cm and uneven borders field geometry and MC calculation discrepancy degree are 0.8662%, 0.8794% and 0.2314%, 0.8170%, respectively. Conclusion: The results provide a reliable basis for the clinical use of MLC. Abstract  
        关键词：FFF;MLC;Monte Carlo;Dose characteristics;Clinical measurement   
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        发布时间：2021-03-03
      • LI Lei,LI Xiaoyan,JIANG Shubin,WU Xiaoli,LI Zongjun
        Vol. 38, Issue 10, Article number: 100204(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100204
        摘要：Background: Concerning radiation hardness assurance testing of microelectronic devices, there is rigorous requirement for the dose rate uniformity of irradiation field. With existing methods, the source rods of single-plate irradiation facility cannot be configured properly in the source plaque, which consequently form the prospected irradiation field. Purpose: This study aims to construct a new method to realize the optimal deployment of source rods and meet the requirements of radiation hardness assurance testing. Methods: The new method was realized by constructing mathematical model and designing improved greedy algorithm. The algorithm mainly contained three aspects. First of all, there was the thought of existing greedy algorithm, which is to determine position of source rods with the objective function defined by uniformity of dose rate at the reference points. In addition, the position of source rods was constricted according to empirical method. Finally, the global searching ability was improved by using enumeration technique. Results: For radiation hardness assurance testing, this method was able to construct irradiation field with dose rate uniformity no more than 1.02, and it was better and 100 times faster than the empirical method. As for irradiation process, the dose rate uniformity and efficiency obtained by this new method is similar to the existing methods such as greedy algorithm and plant growth simulation algorithm. Conclusion: This new method is effective for both the radiation hardness assurance testing and the irradiation process applications. Abstract  
        关键词：Single-rack cobalt source;Optimization of source pencil deployment;Greedy algorithm;Radiation hardness assurance testing   
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        发布时间：2021-03-03
      • LI Sasa,CHENG Zhiqiang,LI Yangjuan,LONG Dewu,GONG Yu,DOU Qiang,WU Minghong,LI Qingnuan
        Vol. 38, Issue 10, Article number: 100301(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100301
        摘要：Background: The fluoride volatility process has been developed to recover uranium from spent nuclear fuel. And the fluoride adsorption technique is usually applied in the purification and collection of UF6 during the fluoride volatility process. Purpose: This study aims to investigate the characteristics and sorption performance of a novel sorbent CeO2/NaF synthesized by doping NaF with CeF3. Methods: With polymer sodium carboxymethyl cellulose (CMC) as a binder and pore-forming agent, CeF3 and NaF was mixed according to a mass ratio of 4:9:62, and then water were added (the ratio of CMC to water is 1:6). The porous CeO2/NaF adsorbent particles were prepared by a mixing, molding and sintering process. The characteristics and adsorption performance of the adsorbent particles were analyzed and characterized. Results: Specific surface area of CeO2/NaF was (0.84±0.04)m2·g?1, which was twice of NaF sorbent made under the same process. Porosity was 42.2%, which was larger than that of NaF sorbent. The initial adsorption rate of MoF6 on CeO2/NaF was much higher than that of NaF sorbent. The temperature zone for desorption of MoF6 from CeO2/NaF ranged from 150°C to 300°C, while there were two desorption zones for desorption of MoF6 from NaF sorbent, which varied from 100°C to 300°C and 350°C to 400°C, respectively. This phenomenon showed that CeO2 might stabilize Mo6+ in MoF6. Conclusion: The physical properties of NaF could be changed by doping with CeO2, and its adsorption performance was also improved. Abstract  
        关键词：NaF;Adsorbent;CeO2 doped;MoF6;TG/DTG   
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        发布时间：2021-03-03
      • TANG Lei,FU Zhonghua,LIU Xuemei,LONG Kaiming
        Vol. 38, Issue 10, Article number: 100302(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100302
        摘要：Background: Constant current coulometry is one of the most precise methods in total uranium measurement, especially for pure uranium sample. Purpose: This study aims at the whole experimental flow conditions for total uranium measurement using constant current coloumetry. Methods: U3O8 and uranium standard solution were prepared. And various experimental conditions for phosphorus acid dosage, Fe(II) dosage, oxidizer dosage, oxidation temperature and coexisting ions etc., were reviewed while measuring total uranium of samples with different weights of standard uranium solutions added in. Results: With optimized flow, total uranium weights in different uranium standard solutions were measured. For 50 mg total uranium added in, the combined uncertainty was 0.12% by constant current coulometry. Conclusions: This method can be used to measure total uranium content in pure uranium sample, and phosphorus acid plays a key role. When the concentration of phosphoric acid is more than 10 mol?L?1, the reduction reaction can be conducted at room temperature. Abstract  
        关键词：Uranium;Constant current;Coulometry   
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        发布时间：2021-03-03
      • ZHU Shengben,DING Kaizhong,DU Qingqing,FENG Hansheng,LU Kun,LIU Chenglian,SONG Yuntao
        Vol. 38, Issue 10, Article number: 100401(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100401
        摘要：Background: Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) is cooperating with India's Tata Consultancy Services (TCS) and International Thermonuclear Experimental (ITER) to build a new measurement and control system engineering for high temperature superconducting current lead (HTSCL) under the framework of CODAC (Control, Data Access and Communication). Purpose: This study aims to design a data acquisition and control system for this project that was implemented according to the requirements of CODAC system. Methods: It contains the fast controller, the conventional Programmable Logic Controller (PLC) system, i.e. the Siemens 300 series and 400 series PLC, is applied for slow controller and data acquisition sub-system, interlock sub-system using the integrated module of CODAC. Fast controller and quench detection sub-system were implemented by using National Instruments (NI)’s NI PXIe-6259, NI 9219, etc. modules and the LabVIEW programming with embedded Experimental Physics and Industrial Control System (EPICS) interface. Each subsystem is developed and applied by following the framework standard of ITER CODAC. Results: This proposed system has passed the second round of testing, showing that it full fills the experimental requirements of HTSCL test. Conclusion: The measurement and control system of HTSCL was designed completely in accordance with of ITER CODAC standard, it follows strictly the CODAC specification of ASIPP and ITER international organization. Most importantly, it’s the first time to combine CODAC and interlock protection system of ITER for real physical performance test, it can be used as a model of CODAC norms in the future. Abstract  
        关键词：ITER;HTSCL;CODAC;Measurement and control system;EPICS   
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        发布时间：2021-03-03
      • YANG Jun,SU Haijun,GUO Honglei,LI Deming
        Vol. 38, Issue 10, Article number: 100402(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100402
        摘要：Background: A small accelerator monitoring system based on local mode cannot meet the challenge of accelerator manufacturers and the accelerator users in the internet era. Purpose: This study aims to realize the remote monitoring by designing a remote monitor and control system for industrial small accelerator. Methods: Under the client/server (C/S) framework, OLE for Process Control (OPC) protocol is adopted for the data communication between client side and server end. Visual C++ programing is applied to implement functionalities such as remote monitor, remote control, equipment and authorization management and others on both sides accoring to their functional localization. Results: Testing results show the system has high real-time, stability and expansibility, which is convenient for user to monitor accelerators and change the service mode of accelerator. Conclusion: The system not only helps manufacturer to reduce the cost of accelerator maintantance, but also has a broad application prospects for industrial small accelerators. Abstract  
        关键词：Small accelerator;Remote monitor and control;VC++   
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        发布时间：2021-03-03
      • WANG Qi,BAO Jie,HOU Long,RUAN Xichao,SU Xiaobin,JING Hantao,LI Qiang
        Vol. 38, Issue 10, Article number: 100403(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100403
        摘要：Background: The fission ionization chamber is constituted by 235U and 238U materials as monitor in China Spallation Neutron Source (CSNS) reverse angle. Purpose: This paper mainly introduces the whole system time precision influence on the energy resolution and the actual measurement corrections. Method: The flux energy spectrum is measured accurately using n-TOF method. Results: The time resolution which is caused by energy resolution is proportional to 3/2 power energy, and the correction is induced less than 0.1% due to differences of the standard cross section energy. Conclusion: The experimental results show that the design of the ionization chamber can meet the requirements of CSNS neutron flux measurements. Abstract  
        关键词：Time resolution;Neutron spectrum;Fission ionization chamber   
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        发布时间：2021-03-03
      • WEI Shuping,LI Lan,CHENG Shisi,ZHU Jianping,TAN Yi
        Vol. 38, Issue 10, Article number: 100601(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100601
        摘要：Background: The mixed oxide (MOX) fuel is made from UO2 and PuO2 by post-processing of the spent duel of pressed water reactor (PWR). It has a good future for wide application but needs plenty of analyses of its characteristics prior to being used in the reactor. Purpose: This study aims to analyze the radiation characteristics of MOX fuel compared with the traditional core fuel. Methods: In accordance with the fuel management of M310 nuclear power plant (NPP) with 30% core filled with MOX fuel assemblies, fast neutron fluence, displacement per atom (DPA) rate on reactor pressure vessel (RPV) and forward factor of irradiation surveillance of the reactor core are studied and compared with both the traditional high leak reactor core with UO2 assemblies in equilibrium cycle and the low leak reactor core with UO2 assemblies which is minority in China. Results: The former comparison results show that the change of the fast neutron fluence and DPA rate on RPV are decreased by 20%, the fluence rate of irradiation surveillance in the direction of 343° is decreased by 8%, forward factor of irradiation surveillance in the direction of 343° is increased by 15%. The latter comparison results show that the change of the fast neutron fluence and DPA rate on RPV are increased by about 40%. Comparing the MOX fuel with the UO2 fuel on the same power level independently, it shows that MOX fuel releases 7% more fast neutron than UO2 fuel. Conclusion: The reactor core with MOX assemblies has less damage than the traditional high leak reactor core with UO2 assemblies. Abstract  
        关键词：MOX;RPV;Fast neutron fluence;DPA;Forward factor   
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        发布时间：2021-03-03
      • YU Jiangmei,YU Jun,GONG Xueyu,XIE Baoyi,ZHANG Neng
        Vol. 38, Issue 10, Article number: 100602(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100602
        摘要：Background: Zonal flows are the electrostatic modes with structures of toroidal symmetry and poloidal symmetry, which play an important role in restraining turbulences. In the process of turbulence suppression, the poloidal rotation widely exists in tokamak plasmas. Purpose: In this study, the effects of the poloidal rotation on zonal flows in tokamak plasmas are concluded. Methods: With the dispersion relation derived by using ideal MHD model with the adiabatic approximation, the frequencies of zonal flows are deduced. Results: Firstly, the frequency of the geodesic acoustic mode (GAM) increases with respect to the poloidal Mach number when adiabatic coefficient is 5/3. Secondly, the frequency of the sound wave (SW) increases with respect to the poloidal Mach number when adiabatic coefficient is 5/3. Thirdly, the frequency of GAM with γ=1 is different from that when γ=5/3. The fourth, the frequency of SW with γ=1 is different from that when γ=5/3. The last, the ratio between the cos and sin components of density perturbation for GAM is a very small value in the poloidally rotating plasma. Conclusion: It is shown that the frequencies of the zonal flows with the adiabatic approximation, increase with respect to the poloidal Mach number, but differ in numerical value of the frequencies of the zonal flows with the isothermal approximation. In contrast to the pure standing wave form in static plasmas, the density perturbations consist of a standing wave superimposed with a small amplitude traveling wave in the poloidally rotating plasma. Abstract  
        关键词：Tokamak;Zonal flows;Frequency;The poloidal rotation of plasmas   
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        发布时间：2021-03-03
      • SONG Mingqiang,ZHOU Tao,CHEN Baixu,HUANG Yanping,XIA Bangyang
        Vol. 38, Issue 10, Article number: 100603(2015) DOI: 10.11889/j.0253-3219.2015.hjs.38.100603
        摘要：Background: Supercritical water reactor (SCWR) is the only one that uses light water as a coolant among all fourth generation nuclear reactors. Purpose: This study aims to investigate the characteristics of supercritical water heat transfer in various pipelines. Methods: The models of rectangular, triangular, circle and annular channels are employed, with equivalent diameters of 2 mm, 3 mm and 5 mm for each of them. Based on these models, heat transfer charactersistics of supercritical water in different shape channels at certain mass flow and fluid velocity were calculated via ANSYS CFX. Results: There are two situations for the same equivalent diameter: in the condition of constant mass flow rate, the heat transfer property of circle channel outperforms other three types of channels, and the smaller equivalent diameter channels, the better of the heat transfer. In constant fluid velocity condition, the heat transfer property of annular channel presents best performance over others, and the smaller equivalent diameter channels, the better of the heat transfer in subcritical condition whilst the bigger equivalent diameter channels, the better of the heat transfer in supercritical condition. Conclusion: Compared with the experimental results, the model can provide a certain reference for the design of supercritical water reactor. Abstract  
        关键词：Different shape channels;Supercritical water;Heat transfer characteristics   
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