用三梯度法测量束流发射度的研究

准确测量发射度对加速器束流的调制和性能的评估极端重要，本文介绍在HIRFL(兰州重离子加速器)现有设备基础上，利用三梯度法测量束流发射度的系统，讨论了测量原理和方法，以及测量中要注意的问题．并对数据的计算处理做了详述。专门设计了一套软件系统，以实现束流发射度、束流剖面等束流参数的实时测量。该系统具有可靠性好、测量直观、测量较准确等优点。     

集装箱检测系统中射线束流中心测量方法的研究

在集装箱检测系统中，射线的实际束流中心可能与光学法测量的束流中心存在差异。试图探讨一种新的实验方法来解决测量实际的束流中心问题。在假设加速器射出的束流横截面，其强度呈高斯分布的条件下，讨论分析了一种精细测量系统柬流横截面强度分布的方法，并用实验对这种方法的正确性做了验证。这种方法对监测、调试射线成像系统的性能，具有重要的意义。     

基于容性感应探针测量方法的研究

介绍了利用兰州重离子加速器束流输运线上的圆柱型容性感应探针进行无阻挡束流强度测量方法的研究。该方法在测量束流相宽和中心相位的同时通过对感应束流信号的计算．进行束流强度监测,以满足HIRFL束流诊断系统在线测量及调束的要求;说明了测量束流感应信号并从中提取束团相宽,束流相位及束流强度等信息的原理;介绍了测量系统装置及虚拟仪器技术在本系统中的应用,并给出了测量结果和测量精度的分析。     

基于闪烁凝胶的放疗二维剂量验证系统研制及可行性研究

为实现放疗二维剂量验证结果的实时、高分辨获取,基于灌装好的组织等效闪烁凝胶材料和相机等光学元器件搭建了剂量测量系统,并对该系统在IMRT质控剂量验证中的可行性进行实验验证。采用TPS剂量值对放疗均匀射束闪烁凝胶发光图像的像素灰度值进行标定。构建便于分区域对比分析的放疗计划,利用标定系数将凝胶闪烁光分布转换为剂量的二维分布。利用平板电离室对放疗计划进行测量,将凝胶系统与平板电离室的测量结果进行对比。结果显示,凝胶系统的测量分辨率远高于平板电离室;在有效成像区域内,凝胶系统的测量结果与平板电离室测量结果相对误差小于5%。这充分说明基于闪烁凝胶的放疗二维剂量验证系统在IMRT质控剂量验证中具有较高的可行性,尤其是对高剂量梯度放疗计划的实时、高分辨验证,后续深入开发可用于临床剂量验证。     

海关集装箱检测用电子直线加速器聚集线圈磁场设计与测试

介绍了在电子直线加速器粒子动力学基础上进行聚集线圈轴向磁场的设计；利用ＬＩＮＥ－ＡＣＣ／ＰＣ程序模拟计算，给出了不同初始发射度情况下满足束流包络要求的各种聚焦磁场数据。对已经加工好的聚焦系统进行了磁场分布测量，并将实际磁场与理论计算进行了比较。上述工作为确定聚焦线圈的设计方案和加速器的出束实验提供了可靠、丰富的数据。     

兰州高能电子成像实验平台电子束团长度测量研究

为提高高能电子成像的时间和空间分辨率,实验需低能散、低发射度、短脉冲的高品质束流。本文利用相干渡越辐射能谱分析法测量基于热阴极微波电子枪的高能电子成像用直线加速器的电子束团长度。通过用迈克尔逊干涉仪测量太赫兹辐射能谱,利用自相关曲线拟合法得到电子束团长度。实验结果表明,当束流宏脉冲峰值强度约为24 mA,即电荷量约为15 pC时,电子束团均方根长度约为0723 5 ps。另外,用Kramers Kronig(K K)相位分析法可重建一种可能的电子束团纵向分布。电子束团长度测量的研究可优化束流品质,对后续高能电子成像实验有重要的参考意义。     

海关集装箱检测用电子直线加速器聚焦线圈磁场设计与测试

介绍了在电子直线加速器粒子动力学基础上进行聚焦线圈轴向磁场的设计；利用ＬＩＮＥ－ＡＣＣ／ＰＣ程序模拟计算，给出了不同初始发射度情况下满足束流包络要求的各种聚焦磁场数据。对已经加工好的聚焦系统进行了磁场分布测量，并将实际磁场与理论计算进行了比较。上述工作为确定聚焦线圈的设计方案和加速器的出束实验提供了可靠、丰富的数据。     

HI—13串列加速器大厅辐射剂量实验研究

本文报道了对ＨＩ－１３串列加速器大厅内辐射剂量进行了实验研究获得的一些结果，确定了供束时沿束流输运线主要辐射源的分布，给出了加速器大厅辐射产生的特点和规律；建立了加速质子、氘核等较轻粒子辐射水平较高时加速器大厅辐射场分布的计算模式，此外还介绍了对剩余射场的监测结果。     

纵向和横向高斯型束团发射度增长的比率关系

采用直线加速器中的有限圆柱空间电荷模型,并假设该有限圆柱体电荷密度分布在纵向z和横向γ都满足高斯分布,推导得到了该电荷束团的自场能与发射度增长公式;通过数值模拟计算,给出了束流发射度增长随束团参数和加速器系统参数变化的图表曲线,讨论了     

电荷束团非均匀密度分布引起的发射度增长

直线加速器中电荷束团的非线性效应是导致束流发射度增长的一个重要原因。文中给出了直线加速器中几种常见的非均匀密度分布的有限长空间电荷束团所具有的非线性自场能，即纵向非均匀电荷密度分布分别为水袋型，抛物线型，而横向密度分布为均匀型，水袋型，抛物线型及高期型等各种组合非均匀密度分布的自场能公式，并得到了由束团非线性的均匀电荷密度分布引起的束流发射度增长。     

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.