用CR—39固体径迹探测器测定重带电粒子的Bragg峰位

采用ＣＲ－３９固体径迹探测器，根据辐射损伤密度沿粒子的径迹分布规律，测定了经３、４ｃｍ空气降能和φ１ｍｍ孔准直的α粒子（５．１５ＭｅＶ）的Ｂｒａｇｇ峰位。对于通过３ｃｍ空气后能量降至～１．２ＭｅＶ的α粒子，在ＣＲ－３９中的Ｂｒａｇｇ峰位大约在７μｍ深度处，理论计算值在６．１４μｍ，实验值与理论值符合得较好。     

CR-39核径迹探测器的标定试验

采用５０ＭｅＶ／ｕ＾１２Ｃ离子对ＣＲ－３９核径迹探测器进行了标定,初步获得拟合公式ＶＴ＝Ｃ·ＬＥＴＣＲ－３９＾α斜率Ｃ为０．００８３（μｍ／ｋｅＶ）＾１．４８５５μｍ／ｈ）,指数α为１．４８６５。     

7MeV／u~（16）O~（6＋）离子在CR－39固体径迹探测器中投影射程的确定

采用与生物样品等效的ＣＲ－３９作为固体径迹探测器来测定７ＭｅＶ／ｕ１６Ｏ６＋离子注入该种材料中的投影射程，利用实验观测到的数据，采用蚀刻速率比和剩余射程统计分布规律的方法，分析和讨论了这种重离子在ＣＲ－３９中的投影射程（即离子注入深度）．两者符合较好，分别为３２．５±６．２μｍ和３０．５±６μｍ。本工作为重离子注入生物样品定点定位诱变研究提供数据。     

国产与美国CR－39固体径迹探测器探测中子性能的比较研究

用Ａｍ—Ｂｅ中子源照射国产ＳＹ－２型ＣＲ－３９与美国ＣＲ—３９固体径过探测器，在蚀刻时间较短时，测量它们表面径迹密度与蚀刻时间的变化，求得单位质量ＣＲ－３９中可蚀刻径迹数目，并在蚀刻时间较长时，测量两种ＣＲ－３９表面径迹密度的饱和值，对两种ＣＲ—３９探测器进行对比。测量表明，国产ＳＹ—２型ＣＲ—３９与美国ＣＲ－３９探测快中子的灵敏度在误差范围内符合，它们具有相同的快中子灵敏度。     

热中子辐照提高掺硼YBaCuO超导体Jc的研究

掺杂天然硼的熔融织构生长（Ｍｅｌｔ－ｔｅｘｔｕｒｅｄＧｒｏｗｔｈ）的ＹＢｘＢａ２Ｃｕ３Ｏｙ（ｘ＝０．０１５,０．０３５）超导体经注量为５＊１０＾１７ｃｍ＾－２的热中子辐照后,磁临界电流密度Ｊｃ增至３．８倍。＾１０Ｂ（ｎ,α）＾Ｌｉ、＾７Ｌｉ＊（Ｑ＝＋２．７９ＭｅＶ）核反应出射的高能粒子能在超导体中产生均分布的,可以作为磁通钉扎中心的辐照伤,以便提高Ｊｃ。掺硼超导体热中子辐照后射性副产物的半衰期较短     

10mm单层结构蜂窝状漂移室的制作与测试

本文总结了ＨＥＲＡ－Ｂ外部径迹系统北京合作组关于ＭＣ２－１０型蜂窝状漂移室的制作和测试情况。室平均效率近似为（９９．５±０．８）％，当高压大于２３００Ｖ时，效率呈饱和状态。在气体ＣＦ４／ＣＨ４（８０／２０）中，高压为２４００Ｖ时室的串扰小于３％。室中电子平均漂移速度约为１０５μｍ／ｎｓ，最大漂移时间小于８０ｎｓ。以上测试结果均达到了设计要求。     

用主动式活性炭盒测定室内环境的^222Rn和^220Rn浓度

把φ１０ｃｍ被动式活性炭盒稍加改装后进行主动式空气采样，用高效率ＨＰＧｅγ谱仪测量＾２２２Ｒｎ／＾２２０Ｒｎ短寿命子体的３５２ＫｅＶ／２３９ＫｅＶ的γ射线净峰面积，经刻度后可财得到空气中＾２２２Ｒｎ的浓度，＾２２２Ｒｎ和２２０Ｒｎ的实测刻度因子分别为０．２６３Ｂｑ＾－１．ｍ＾３．ｍｉｎ＾－１和０．１８２Ｂｑ＾－１．ｍ＾３．ｃｍ＾－１，给出室内环境和经各种空气处理的试验性测量结果，＾２２２Ｒｎ浓度为     

采用电离室测定重离子束的Bragg峰位

从探索定点定位诱变要求出发，提出了重离子束Ｂｒａｇｇ峰可作为一个有用手段，阐述了测量重离子束Ｂｒａｇｇ峰的原理和实验装置，采用一对电离室测定初始能量为５０ＭｅＶ／ｕ左右＾１４Ｎ＾７＋离子束在物质密度归一到小麦材料后的Ｂｒａｇｇ峰位。最终得到峰位深度约为４．８５ｎｍ，离子束的最大射程为５．５ｍｍ左右。     

^99mTc标记环己二酮二肟及其甲基硼酸加成物和初步动物实验

实验结果表明，＾９９ｍＴｃ－ＣＤＯ的标记率受体系的ｐＨ值影响较小，而＾９９ｍＴｃ－ＣＤＯ－ＭｅＢ只有在ｐＨ＝３．５－４．０时标记率才能大于９０％。小鼠体内分布实验表明，＾９９ｍＴｃ－ＣＤＯ－ＭｅＢ在动物心肌中较高的吸收，但随时间延长而迅速清除。心／肝比值在给药后１、５和１０ｍｉｎ时分别为３、１．５和０．８。＾９９ｍＴｃ－ＣＤＯ在心、脑中的浓聚明显低于９９ｍＴｃ－ＣＤＯ－ＭｅＢ。     

地表空气中^7Be浓度

杭州附近地区的测量结果表明，地表空气中＾７Ｂｅ的浓度全年平均为４．６±２．０ｍＢｑ·ｍ＾－３，比ＵＮＳＣＥＡＲ的报告值高出５０％－８０％。其中１０、１１、１２月份的均值最高，达６．８±１．１ｍＢｑ·ｍ＾－３；２、６、７月份的均值最低，在２．０±０．１７ｍＢｑ·ｍ＾－３；４、５月份的浓度接近于全年平均值；表现出明显的与降水有关的季节性变化，而未显示出ＵＮＳＣＥＡＲ报道的与平流层沉降有关的春天最高、晚     

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。     

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.     

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.     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

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.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.     

微型X射线管空气比释动能和能谱的测量

为研究微型X射线管的特性,通过电离室测量光管出射口30 cm远处的空气比释动能,使用高纯锗探测器分别测量了Ag过滤和Cu过滤下的X射线能谱。结果表明,空气比释动能随电流的增加有线性增加的趋势,能谱图明显的观察到银的两个特征X射线。完成了微型X射线管空气比释动能和能谱的测量方法以及实验测量的工作,为微型x射线管下辐射质的建立提够了条件基础。     

Gamma-ray attenuation technique for measuring void fraction in horizontal gas-liquid two-phase flow

The measurement of void fraction is of importance to the oil industry and chemical industry. In this article, the principle and mathematical method of determining the void fraction of horizontal gas-liquid flow by using a single-energy γ-ray system is described. The γ-ray source is the radioactive isotope of 241Am with γ-ray energy of 59.5 keV. The time-averaged value of the void fraction in a 50.0-mm i.d. transparent horizontal pipeline is measured under various combinations of the liquid flow and gas flow. It is found that increasing the gas flow rate at a fixed liquid flow rate would increase the void fraction. Test data are compared with the predictions of the correlations and a good agreement is found. The result shows that the designed γ-ray system can be used for measuring the void fraction in a horizontal gas-liquid two-phase flow with high accuracy.