BEI-1电子直线加速器定时触发系统

本文介绍了一个完整的全集成电路化的定时触发系统,用于双功率源馈送功率BEI-1电子直线加速器中。它是由七个专用NIM标准插件组成,即:同步、异步基准脉冲发生器,用于电子枪、行波管、速调管调制器、能量倍增器的延迟放大电路以及快速保护电路。这套系统在BEI-1电子直线加速器上能正常运行,证明它的各项性能达到了设计指标。     

BEPCⅡ直线定时系统光信号收发器的研制

定时系统为BEPCⅡ直线电子枪、调制器和正电子源等设备提供精确的同步触发信号.因光纤介质的传输损耗低,使用光纤收发器传输同步触发脉冲信号,不但可以实现信号的远距离传输,同时保障了信号的电气隔离,增强了系统抗噪声能力.目前,自主研发的OTB插件已经投入了BEPCⅡ的直线定时系统的运行,结果表明系统性能达到并优于定时系统的设计指标.     

上海光源150MeV直线加速器传输波导相长度测量与调整

上海光源直线加速器加速器主体由电子枪、次谐波束聚器、基波聚束器及四台加速管组成,其功能是通过低能输运线向增强器注入150 MeV能量的电子束.直线加速器2006年12月开始安装,2007年5月出束,10月完成束流调试,向增强器供束,束流指标达到设计目标.传输波导相长度的测量与调整是微波系统及加速器建设安装过程中的的关键环节,调试结果直接关系到直线加速器的升能效果,影响到束流其它相关参数.本文阐述了上海光源直线加速器波导相长度测量与调整过程,给出了加速器束流调试的相关指标结果.     

BEPCII直线定时系统光信号收发器的研制

定时系统为BEPCII直线电子枪、调制器和正电子源等设备提供精确的同步触发信号。因光纤介质的传输损耗低，使用光纤收发器传输同步触发脉冲信号，不但可以实现信号的远距离传输，同时保障了信号的电气隔离，增强了系统抗噪声能力。目前，自主研发的OTB件已经投入了BEPCII的直线定时系统的运行，结果表明系统性能达到并优于定时系统的设计指标。     

HI-13 Tandem Accelerator in 2005

直线加速器网络监控系统旨在通过网络远程监视、控制电子直线加速器，从而使管理人员能在不同的地点通过网络监控加速器，及时了解加速器的运行情况并操作加速器。目前已通过开发软件ASR.NET实现了对直线加速器的网络远程监视。     

强流质子加速器时序控制系统

针对一台用于加速器驱动洁净核能源系统研究、高占空比的强流质子加速器,开展强流质子加速器时序控制系统的研究工作.强流质子加速器时序控制系统提供加速器开机运行过程中所需要的触发信号和时钟信号,该系统的准确性和稳定性对于整个直线加速器的正常运行有重要的影响.介绍了基于ALTERA公司Cyclone Ⅲ系列FPGA串口通信硬件...     

速调管管体温差保护装置的研制与应用

速调管是直线加速器系统重要的分系统之一。它是加速器的功率源,加速器的微波功率就是通过速调管放大输出的,因此,速调管的工作状态直接影响加速器的正常运行。速调管工作时,良好的束流聚焦状态非常重要,否则,会引起速调管输出功率下降,甚至会损坏速调管。为了间接判断速调管的     

皮秒加速器的安全联锁设计

皮秒加速器安全保护主要联锁电子枪、476 MHz微波功率源和2856 MHz触发信号以确保人员与机器的安全.本文重点介绍由ADAM5511和基于单片机的定时触发器实现的紧急硬联锁和用以提高系统的运行效率的上位机辅助逻辑设计.经过修改和测试,安全设计已满足机器运行的联锁要求.     

10 MeV辐照电子直线加速器真空系统运行情况

10MeV辐照电子直线加速器的真空系统自2004年5月安装完成后,到目前已运行8个月,其运行状况基本正常。本系统使用5台钛泵,保证达到整个加速器对真空度的要求,使加速器正常、稳定地工作。5台钛泵分别放置于波导、电子枪阴极、加速管入口、加速管出口和扫描盒处。为保证电子枪能够     

2MeV行波电子直线加速器自动频率控制系统

在电子直线加速器中,微波功率源输出频率的稳定性非常重要,它直接影响到加速器整机的物理性能指标。由于微波功率源磁控管的输出频率会随外部工作环境变化而发生漂移,所以必需在电子直线加速器中采用自动频率控制(AFC)系统。讨论了2MeV小型行波电子直线加速器AFC系统的设计要素,分析了微波信号的鉴频原理及鉴频模块的测试结果。结合实际的工作环境,测试了信号处理单元主要功能模块的输出,并对测量结果的精度进行了分析。     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

The preclinical pharmacological study of dopamine transporter imaging agent 18F-FP-β-CIT

The paper is to study pharmacologic characteristics of 18F-FP-β-CIT (18F-N-(3-fluoropropyl)-2β- carbomethoxy-3β- (4-iodophenyl)nortropane) as an imaging agent for dopamine transporter. The radiochemical purity of 18F-FP-β-CIT in aqueous solution was over 95% after standing at room temperature for 4h. Biodistribution displayed rapid uptake in rat brain (1.375 %ID/organ at 5min and 0.100 %ID/organ at 180 min) and the striatal uptake was 1.444,0.731, 0.397, 0.230 and 0.146 %ID/g at 5, 30, 60, 120 and 180 min, respectively. The values of striatum/cerebellum,striatum/frontal cortex and striatum / hippocampus in rat's brain at 30 min were 3.38, 2.17 and 2.40 respectively. The uptake in striatum can be blocked by β-CFT, suggesting that 18F-FP-β-CIT binds to DAT peculiarly. The compound was rapidly cleared from monkey's blood. The striatal uptake was bilaterally decreased in the left-sided lesioned PD rats, compared with normal control. Brain PET imaging studies in normal monkey showed that 18F-FP-β-CIT was concentrated in striatum. The test of undue toxicity showed that the dose received by mice was 1250 times as by human, which indicates that 18F-FP-β-CIT is very safe. So 18F-FP-β-CIT is a promising PET imaging agent for DAT with safety and validity.     

Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

PLASMA SCIENCE AND TECHNOLOGY AUTHOR INDEX TO VOLUME 16(2014)

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Radioactivity levels in soil of salt field area,Kelambakkam,Tamilnadu,India

Soil samples in and around salt field area have been analyzed for natural radioactivity concentration using gamma ray spectrometer.The activity concentration for ~(232)Th,~(238)U and ~(40)K are ranged from 27.88 to 45.27 Bq/kg, from BDL to 13.30 Bq/kg,and from 135.54 to 381.28 Bq/kg,respectively.The measured activity concentrations for these radionuclides were compared with world average activity of soil.The average activity concentration of ~(232)Th in the present study is 1.19 times higher than world median value while the activity of ~(238)U and ~(40)K is found to be lower. The absorbed dose rates due to these radionuclides were calculated.The average absorbed gamma dose rate due to the presence of ~(232)Th,~(238)U and ~(40)K in soil samples is 36.99 nGy·h~(-1).These results indicate no radiological anomaly. The data presented in this study will serve as a base line survey for primordial radionuclides concentration in the study area.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.