国产CR39蚀刻材料双层片蚀刻技术研究

使用＾２３９Ｐｕ放射源辐射国产ＳＹ－１型ＣＲ３９片，研究了该片子的双层片电化学蚀刻参数特性。提出的双层片蚀刻技术可以提高蚀刻速度，消除电击穿干扰。实验初步确定的蚀刻条件，化学预蚀刻，电化学蚀刻。利用液体盐标准氡源研究了该片子的测氡性能，采用Φ５０×３０ｍｍ扩散取样盒测量，实验确定的氡刻度转换因子为３．５１±０．１３径迹．ｃｍ＾－２ｋＢｑ＾－１ｈ＾－３。     

G—M计数管用于环境γ辐射监测

为测量环境γ辐射周围剂量当量,对Ｇ－Ｍ计数管的自身本底和能量响应特性进行了实验研究。采用铅,锡两种金属材料做为过滤器改变计数管的能量响应,为拓宽仪表量程采用两种尺寸计数管。两种计数管在６０ｋｅＶ至６６２ｋｅＶ范围内,Ｈ＾＊（１０）／Ｘ随能量变化与ＩＣＲＵ４７号报告结果最大偏离分别为－２３％和＋２４％,仪表量程为１０ｎＳｖ．ｈ＾－１－１０ｍＳｖ．ｈ＾－１,探测下限可达到４０ｎＳｖ．ｈ＾－１。     

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     

北京市从事^125I工作的人员甲状腺中^125I的监测及剂量估算

为了控制工作人员的内照射剂量水平，我们对北京从事＾１２５Ｉ工作的人员甲状腺中的＾１２５Ｉ进行监测，并估算了工作人员所受的内照射剂量。共监测８个单位，７９人，其中７８人有明显的＾１２５Ｉ内污染。所测到的甲状腺中＾１２５Ｉ滞留量为０．０１－６．３２ｋＢｑ。人均待积剂量当量为０．３５ｖＳｖ。总的集体待积剂量当量为２７．７人．ｍＳｖ。     

中国科学院近代物理研究所外照射个人剂量监测（1986—1995）

中国科学院近代物理研究所工作人员所受职业照射主要来自光子外照射。本文介绍１９８６－１９９５年近物所放射工作人员外照射个人剂量监测的方法及结果。在１９８６－１９９５年间,共监测１２１７人（次）,年个人有效剂量平均值为０．１０ｍＳｖ;个人年有效剂量〈０．１０ｍＳｖ的有１０４６人,占监总总人数的８６％;个人年有效剂量在５．０－１０ｍＳｖ范围的只有４人,仅占０．３％;最高个人年有产剂量为１０ｍＳｖ,是加速     

环境^222Rn和^220Rn子体所致气管支气管剂量的模拟测量

本文介绍了用Ｈｏｐｋｅ等人提出了的“支气管剂量计”测定环境空气中＾２２２Ｒｎ和＾２２０Ｒｎ子体所致的气管支气管子（Ｔ－Ｂ区）剂量。通过模拟测量人的鼻腔（Ｎ区）和Ｔ－Ｂ区的＾２２２Ｒｎ和２２０Ｒｎ子体沉积份额，分别计算出以ｍＧｙ／ＷＬＭ和ｍＳｖ（ａ．Ｂｑ．ｍ＾－３）为单位表示的Ｔ－Ｂ区的剂量转换因子，在实验室关闭门窗，开启空调以及施放正，负离子等不同的空气处理情况（照射条件）下，比较了剂量转换因子的     

有关住宅内和工作场所中氡的防护问题

本文主要根据国际放射委员会第６５号出版物介绍住宅内和工作场所中氡子体照射及有关防护问题。给出的氡子体暴露量与有效剂量转换因子，对工作人员为１．４ｍＳｖ（ｍＪｈｍ＾－３）（５ｍＳｖＷＬＭ＾－１），对公众成员为１．１ｍＳｖ（ｍＪｈｍ＾－３）＾－１（４ｍＳｖＷＬＭ＾－１）。对住宅内采取补救措施的氡浓度的行动水平为２００－６００Ｂｐｍ＾－３。     

一个单采样头的支气管剂量计

提出了一个只有一个采样头的便携式支气管测量计，采样头分别由一层４００目金属筛网和滤膜组成，采样气流面速为１２ｃｍ／ｓ，采样后分别对筛网和滤膜同时测量其总α计数，可得氡子体照射气管支气管（Ｔ－Ｂ区）的年有效剂量（ｍＳｖ／Ａ）如将采样头与主动式活性炭盒串接采样测定氡气浓度，则还可以计算出以μＳｖ／（ａＢｑ．ｍ＾－３）为单位的剂量转换因子，给出了这种支气管剂量计的设计思想和试验性测量结果。     

北京市医院核医学科工作人员内照射个人监测及剂量估算

报道了１９９５年北京市部分医院核医学科工作人员的归照射个人监测结果，并简要介绍了监测方法和剂量估算方法。共监测了２０个单位的１５７人，占北京市该类人员应监测人数的３／４以上。总的集体待积有效剂量当量为１．４×１０＾－２人；Ｓｖ年人均待积有效剂量当量为８．９×１０＾－２ｍＳｖ。被监测的全部工作人员年待积有效剂量当量均在年剂量限值的１／１０以上。     

球形环体积中子源的中心柱的机械设计研究

本文描述了基于球形环的体积中子源（ＳＴ－ＶＮＳ）的中心柱（ＣＰ）的机械和热力设计问题。目的是为用于聚变装置的核技术的发展以及包层设计的审核提供了个试验台。如文中所给出的，随着物理和工程设计的假设条件从适度水平提高到较高水平，ＶＮＳ能够分阶段在０．５－５．０ＭＷ／ｍ＾２的中子壁负载下运行。由于在２ＭＷ／ｍ＾２的壁负载下运行将是合适的，所以设计裕量得到保证。装置的大半径为１．０７ｍ，小半径为０．７７ｍ     

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.