D-T中子穿透铁球伴生γ射线泄漏能谱实验研究

建立了厚度为3,6,11,16,21.8cm的铁球基准装置,用BC-501A谱仪测量了D T中子穿透铁球伴生γ射线泄漏能谱,能量范围为0.5～5MeV。通过康普顿反冲电子法解谱得到γ射线泄漏能谱,通过分析能谱,发现铁球厚度对能谱变化影响有一定的规律。γ射线能谱实验误差为4%～6%。     

14 MeV中子穿过组合材料引发238U绝对裂变率的测量

为检验计算方法与参数，用小型平板铀裂变室测量了铁球壳表面沿赤道方向不同位置14 MeV中子穿透实验模型后引起的。^238U绝对裂变反应率，并与MCNP/4A和ENDF/B-V库数据计算结果相比较。实验总误差为6．1％。     

14MeV中子穿透铁圆柱的活化反应率测量

用几种阈能活化探测器测量了14MeV中子穿过不同厚度铁圆柱体的绝对活化反应率径向分布。利用MCNP4A／5程序和FENDL-2、ENDF／B-Ⅵ数据库对实验进行了模拟计算,并将计算结果与实验进行了比较。实验不确定度为6.1-7.1％。     

碳材料反射中子的238U裂变反应率测量和计算

用小型贫化铀裂变室和俘获探测器测量了D-T聚变中子在碳材料反射体上反射中子引起的^238U裂变反应率分布。比较了无碳材料反射体的测量结果。实验测得的^238U裂变反应率合成不确定度为5．1％～6．4％。实验结果与用MCNP／4A程序和ENDF／B-Ⅳ库数据计算的结果在误差范围内符合。     

液体闪烁探测器中子γ射线测量研究

液体闪烁体对中子的响应函数,利用O5S蒙特卡罗程序进行计算,γ射线响应函数利用MATHA蒙特卡罗程序进行计算。分别对液体闪烁探测器(n,γ)分辨品质测量、Am-Be中子源的中子谱和γ射线能谱的测量、铁球在D-T中子照射下泄漏中子和伴生γ射线能谱的测量、水球在D-T中子照射下泄漏中子和伴生γ射线能谱的测量等内容进行了介绍,并对结果进行了分析和讨论。     

D-T中子照射下贫化铀球、钒球介质内中子能谱和伴生γ能谱测量

为获得介质内中子能谱及伴生γ能谱的实验数据，在中心D-T中子照射下，用18mm×20mm的茋闪烁体探测器，测量了与D+束成45°角的水平方向距球心7、10、13、16、19、22cm位置处贫化铀球介质内的中子能谱和伴生γ能谱，以及钒球内与D+束成0°角、距离球心1.8、4.8和8.3cm处的中子能谱和伴生γ能谱。用MCNP/4B程序和ENDF/B-VI库数据对实验模型进行模拟计算，并与实验结果进行了比较。     

液体闪烁探测器中子和γ射线测量研究

液体闪烁体对中子的响应函数,利用05S蒙特卡罗程序进行计算,γ射线响应函数利用MATHA蒙特卡罗程序进行计算。分别对液体闪烁探测器（n,γ）分辨品质测量、Am—Be中子源的中子谱和γ射线能谱的测量、铁球在D—T中子照射下泄漏中子和伴生γ射线能谱的测量、水球在D—T中子照射下泄漏中子和伴生γ射线能谱的测量等内容进行了介绍,并对结果进行了分析和讨论。     

钒球的中子倍增率与活化反应率

以一直径138cm的聚乙烯球作为中子慢化剂与全吸收探测器，采用全吸收法测量了钒球的14MeV中子的泄漏倍增率。用1支与H对热中子具有相同1／V吸收规律的^6Li玻璃探测器的测量子全吸收体的径向中子计数率分布。实验得到了钒球中心D－T中子时的Al、Fe、In和V一组阈探测器的绝对活化反应率的分布。用MCNP／4A程序、ENDF／B－Ⅵ和FENDL－2核数据进行了模拟计算。与实验结果相比较可知：用ENDF／B－Ⅵ库数据的计算结果与实验结果符合良好，而用FENDL－2库数据的计算结果比实验结果约高4％。     

混合辐射场n、γ比调节器设计

为了满足用户对辐射场的特殊要求,需要进一步提高CFBR-II堆的n、γ比值.利用铅对γ射线良好的屏蔽作用,设计了基于铅为主体材料的调节器.通过理论计算,给出了添加不同厚度铅后的n、γ比值.综合考虑调节器对中子能谱的影响以及装置平台承重能力的影响后,实际加工了由每层厚度为1 cm,共4层组成的调节器,并进行了实验测量.结果表明:实验结果与计算结果在许可误差范围内符合.CFBR-II堆辐射场的n、γ比值在1.07×1012～4.87×1012 cm-2·Gy-1(Si)范围内可调.     

γ射线透射法检测输油管道油垢的标定实验研究

用γ射线透射法对新疆克拉玛依油田φ74mm输油管道油垢的检测进行了标定实验研究，测量了该管道的油垢厚度响应曲线，其结果表示为In(N0／N)=0．00392d—0．00677，并研究了保温层对测量结果的影响。实验装置由^137Csγ放射源和Nal(Tl)闪烁探测器组成。测量结果表明：油垢厚度响应曲线是灵敏的，保温层对测量结果影响不大。     

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.     

The control system for SSRF injection and extraction

This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet.     

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.     

有效探测面积大于1000 cm2的正比计数器测量系统性能测试

为对自制的活性面积高达1 000 cm²的大面积源进行表面发射率定值,同时作为现有2πα、2πβ表面发射率标准装置能力的扩充,研制了一套内置式大面积2π多丝正比计数器测量系统,并利用活性区直径为8 mm的²⁴¹Am点源及活性区面积为10 cm×15 cm的大面积²⁴¹Am和⁹⁰Sr-⁹⁰Y源对其进行计量学性能测试。结果表明：计数器内计数响应均匀性优于±0.4%,有效探测面积达1 400 cm²;所得²⁴¹Am源高压坪曲线的坪长为1 400 V,坪斜为0.27%/100 V,坪区内计数变化为0.87%;⁹⁰Sr-⁹⁰Y源高压坪曲线的坪长为300 V,坪斜为0.75%/100 V,坪区内计数变化为0.80%;10次测量重复性好于0.4%,8 h内短期稳定性好于0.3%,1 a内长期稳定性好于0.8%。     

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.