压水动力反应堆燃料元件安全性的监测与分析

为了对１座压水型动力反应堆作燃料元件破损的现场监测，计算了一些裂变产物的主要γ光子用７６．２ｍｍ×７６．２ｍｍＮａｌ探测器测量时产生的光电峰相对计数率随反应堆启动不同时间的变化，并作了监测中的干扰因素分析。计算和分析结果表明：在元件安全性监测中，最适合选择的γ光子能量是２２０．９ｋｅＶ（８９Ｋｒ）、４０２．７ｋｅＶ（８７Ｋｒ）、１９６．３ｋｅＶ（８８Ｋｒ）、５２９．８ｋｅＶ（１３３Ｉ）和８１ｋｅＶ（１３３ｘｅ）。在监测中存在的主要干扰因素是高能γ射线产生的湮没辐射、ｗａｌ探测器周围ｐｂ屏蔽上产生的７５ｋｅＶＸ射线及由１９Ｏ和１６Ｎ产生的γ射线。在１座反应堆２次事故排除的元件安全性监测中，分析方法成功地得到了应用。     

^75Se和^113Sn的KX射线发射几率测量

用＾５４Ｍｎ、＾５７Ｃｏ、＾６５Ｚｎ、＾８５Ｓｒ、＾１０９Ｃｄ、＾１３７Ｃｓ等核素发射的ＫＸ射线和Ｉ（ＫＸ）／Ｉ（γ）比值法在５￣４０ｋｅＶ范围内对Ｓｉ（Ｌｉ）探测器的效率进行了刻度（不确定度小于２％）。在此基础上,用Ｓｉ（Ｌｉ）Ｘ射线谱仪系统和ＨＰＧｅγ射线谱仪系统对核素＾７５Ｓｅ和＾１１３Ｓｎ的主γ射线和ＫＸ射线进行了测量,获得了＾７５Ｓｅ和＾１１３Ｓｎ的ＫＸ射线发射几率,并与文献报道值进行了     

碘化汞探测器的研制进展

使用片状法生长ＨｇＩ２单晶片制砀２０ｍｍ２×０．４ｍｍ探测器在常温下对５９．５ｋｅＶγ射线和５．９ｋｅＶＸ射线的能量分辨率分别为１．９ｋｅＶ和９００ｅＶ。已用于Ｃｕ、Ｐｂ、Ｚｎ等矿样分析，取得了新结果。     

电致冷高分辨率Si（Li）能谱仪

电致冷高分辨率Ｓｉ（Ｌｉ）Ｘ射线能谱分析仪采用电阻反馈前置放大器，灵敏面积为２８ｍｍ＾２Ｓｉ（Ｌｉ）探测器，对＾５５Ｆｅ５．９ｋｅＶＸ射线，能量分辨率（ＦＷＨＭ）为７００ｅＶ左右，对探测器在不同温度下随偏压的变化，致冷功率与温度关系，冷却温度与时间关系进行了研究。     

一台自行组建的低本底Ge（Li）－NaI（T1）反符合γ谱仪

本文报道自行组建的一台Ｇｅ（Ｌｉ）－ＮａＩ（Ｔｌ）反符合γ谱仪的结构和性能。主探测器是φ６１．５ｍｍ×５６．０ｍｍ的同轴Ｇｅ（Ｌｉ）探测器（灵敏体积为１５０ｃｍ￣３），由φ８８．９ｍｍ×７６．２ｍｍ的圆柱形ＮａＩ（Ｔｌ）晶体和外、内径×高为２５４ｍｍ、８８．９ｍｍ×３０５ｍｍ的环形ＮａＩ（Ｔｌ）晶体构成井型反符合探测器，主要的物质屏蔽层是１００ｍｍ铅＋１５ｍｍ钢＋５ｍｍ铜。Ｇｅ（Ｌｉ）探测器对￣（６０）Ｃｏ１３３３ｋｅＶ能量的分辨率为２．４ｋｅＶ，峰康比为４４，相对探测效率为２４％。在反符合屏蔽条件下，谱仪在康普顿坪（３５８—３８２ｋｅＶ）和康普顿端（４６０—４８４ｋｅＶ）的抑制因子分别为５．Ｏ和５．４；康普顿区积分（５０—５９５ｋｅＶ）抑制因子３．６，峰康比（￣（１３７）Ｃｓ点源）为４９４。在１００—２０００ｋｅＶ能区屏蔽室内、外的积分本底比为１：１３１。加反符合和不加反符合条件下的积分本底抑制因子为３．５，加反符合后的积分本底为１７．２ｃｐｍ。当测量时间１０００ｍｉｎ、置信度９５％时，￣（１３７）Ｃｓ的最低可探测活度（判断限）为５．８ｍＢｑ．２４小时内，￣（２４１）Ａｍ、￣（１３７）Ｃｓ和￣（６０）Ｃｏ     

乏燃料后处理溶液中U,Pu的^57Co原激发K—XRF分析

自制一套＾３７Ｃｏ源激发与Ｋ系Ｘ射线荧光（Ｋ－ＸＲＦ）分析系统，用＾３７Ｃｏ的ｋｅＶγ射线激发工艺溶液中Ｕ，Ｐｕ的Ｋ系Ｘ射线荧光，用ＨＰＧｅ探测器－多道微机分析系统进行测量，并以１２２ｋｅＶγ射线康昔顿散射线为内标，建立强度比－浓度校正曲线，快速同地测定了ＰＷＲ乏燃料后处理工艺溶液中Ｕ，Ｐｕ浓度，测定范围为０．５－２００ｇ／Ｌ，精密度为５．０％－１．５％。方法适于ＰＷＲ乏燃料后处理工艺中，Ｕ，Ｐｕ     

14MeV中子在φ600mm贫化铀球中造钚率测量

使用中子活化技术对２３８Ｕ（ｎ，γ）２３９Ｕ反应产物２３９Ｕ衰变后的２３９Ｎｐ子体的２７８ｋｅＶγ射线的绝对测量，获得了１４ＭｅＶ中子在６００ｍｍ贫化铀球中的造钚率。其实验测量值为２．４６±０．０９。２７８ｋｅＶγ射线用高纯锗探测器测量，探测器的有效计数效率用２４３Ａｍ源刻度。６００ｍｍ贫化铀球由７层贫化铀球壳组成，球心有一８０ｍｍ源腔，总重约２．１ｔ。     

大面积Si（Li）探测器

测量了不同温度条件下面积为４９ｍｍ×４９ｍｍ、厚３．５ｍｍ的Ｓｉ（Ｌｉ）探测器的Ｉ－Ｖ特性。Ｓｉ（Ｌｉ）－Ｅ－１和Ｅ－２探测器对＾２３８Ｐｕ５．４９９ＭｅＶ α粒子的能量分辨率例如为５４．４ｋｅＶ和５７．０９ｋｅＶ。     

外延硅dE／dX探测器的研制

本文介绍了厚度为５．２－６．０、１０－１３、１９μｍ，有效面积为２８－１５４ｍｍ＾２的外延硅ｄＥ／ｄＸ探测器的研制工艺，主要用途，测试结果（对９．８７ＭｅＶ α粒子的能损△Ｅ的分辨率为５６－１２８ｋｅＶ）和在核物理实验中的应用。     

锗γ谱仪^110mAg符合相加修正因子测量

通过在ＨＰＧｅ探测器表面及距探头２８ｃｍ处分别测量形状相同的＾１１０ｍＡｇ（６５７．８ｋｅＶ）和＾１３７Ｃｓ（６６１．６ｋｅＶ）体源的全能峰妆计数率,可在避开源活度,发射几度和自吸收修正等条件下,测得在探测器表面测量＾１１０ｍＡｇ６５７．８ｋｅＶγ射线的符合相加修正因子Ｆ０;本文介绍了此测量方法的原理和测量结果。     

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.     

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.     

Gamma radiation levels in the ambient environment of the QNPP Base

Monitoring results of gamma dose rate level in 1992～2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province,are reported in this paper.It is shown that the gamma dose rate of five monitoring sites of 2.5 km to QNPP Base is 84～113 nGy/h,with an average of 96 nGy/h in the 13 years.The average value is close to the background level of 93 nGy/h prior to operation of the QNPP Base,and is lower than the monitoring result of 101 nGy/h at the reference site in Hangzhou City.Within 50 km from the QNPP Base,the cumulative dose rate of the thermoluminescent dosimeter(TLD)is 90 nGy/h,which is lower than the back- ground level of 111 nGy/h.