气泡中子探测器用于个人剂量监测

气泡中子探测器是可重复使用、积分型、无源剂量计。它的体积小,可对中子辐射进行直接、可视的测量。为了将气泡中子探测器用在个人剂量监测中,先验证气泡中子探测器对从0．2～15MeV能量的中子具有平直的能量响应。然后用5．10和1．3MeV的中子考察了气泡中子探测器的线性及其稳定性。     

中子气泡剂量计探测器用于混合中子场中子测量

气泡探测器具有中子实时剂量监测、宽能区中子能量响应稳定和探测限低的优势，因此，它在中子剂量计领域是一项有前景的技术。且被认为是唯一能满足国际放射防护委员会ICRP60要求的个人中子剂量计。目前，本实验室已经研制出具有自主知识产权的中子气泡剂量计。     

中子气泡探测器的研究

气泡探测器被认为是唯一能满足国际放射防护委员会ICRP60要求的个人中子剂量计,它有极高的中子灵敏度,而且适用的中子能量范围可达100eV～10MeV,是核能和民用等核环境中中子     

Study on Preparation of ^182Hf AMS Standards——Chemical Separation of W, Ta From the Sample of Hf

气泡探测器被认为是唯一能满足国际辐射防护委员会ICRP60要求的个人中子剂量计，它有极高的中子灵敏度，而且适用的中子能量范围可以达到100eV～19MeV，是核能和民用等核环境中中子剂量测量迫切需要的工具。     

基于3层硅探测器的主动式中子个人剂量计研制

研制了一种具有能量分辨能力的中子个人剂量计。该个人剂量计由3层硅探测器组成,硅探测器周围装有⁶LiF、聚乙烯和含硼聚乙烯作为转化体、慢化体和吸收体。个人剂量计有直读和解谱两种工作模式。直读模式将中子能区划分为低能、中能和快中子3个能区,可实时测量。解谱模式可获得快中子能区的中子能量分布。利用GEANT4程序模拟了7 MeV γ射线的能量沉积谱,设置适当的甄别域以降低γ射线的影响。采用GEANT4程序模拟了个人剂量计对不同能量入射中子的个人剂量当量率响应。在加速器单能中子参考辐射场中完成了单能中子剂量响应的实验校准,对模拟计算的响应函数进行了实验修正,并得出了不同能区的平均中子个人剂量当量率响应。     

中子气泡探测器用于核测井中子个人剂量监测的研究

为研究国产中子气泡探测器在核测井中子个人剂量监测中的适用性,采用国内研制的中子气泡探测器对核测井运源车外表面、车内兼用储源仓周围等关注点的中子辐射水平进行监测,同时采用进口LB6411型中子周围剂量当量仪进行比对监测。实验结果表明,当运源车兼用储源仓内仅装载中子源时,中子气泡探测器与LB6411的测量结果无显著统计学差异,两者测量结果符合较好,中子气泡探测器的测量结果准确可信;当兼用储源仓分别装载中子源、中子-γ源时,两组中子气泡探测器的测量结果也无显著统计学差异,中子气泡探测器适用于中子-γ混合辐射场中子辐射剂量的测量。中子气泡探测器在运源车现场与在²⁴¹Am-Be源标准中子场中的剂量响应灵敏度因子间的相对偏差为7.4%,验证了其较好的能量响应特性,并显示了在核测井现场条件下用于中子个人剂量监测的适用性。     

超临界事故固体裂变径迹中子剂量计

阈探测器是研究中子能谱的一种有效工具,而中子能谱是解决某些辐射剂最学问题(其中包括确定紧急核事故中子剂量)所不可缺少的资料。用核乳胶和活化阈探测器测量事故中子剂量有一定的局限性。1967年,K.Becker 等人提出用“非照相方法”测量事故中子个人剂量的建议,并用天然铀和聚碳酸酯制作一种简单的裂变径迹个人中子剂量计~([1])。近年来,我们也研制了这种固体裂变径迹中子剂量计。在超临界紧急事故中,应用这种剂量计来测量中子剂量具有许多明显的优点:测量速度快,可测量的剂量范围大,环境适应性强和径迹计数能自动化等。其缺点是剂量计本身固有的γ放射性虽然已降低到很弱,但仍高出环境本底     

基于固体径迹探测的中子个人剂量计性能研究

CR-39固体径迹探测器作为一款被动式的中子个人剂量计,具有方便携带、价格低廉、抗干扰能力强、对γ、β射线不敏感、对快中子响应好等优点。针对新开发的一款中子个人剂量计,根据国际标准ISO 21909-1,对新型中子个人剂量计的CR-39固体径迹探测单元的相关性能开展了实验研究。实验结果表明,CR-39固体径迹探测器具备良好的测读重复性、批次均匀性、剂量线性、稳定性、参考辐射场响应以及对光子不敏感的属性,同时给出了CR-39测量中子剂量的剂量探测下限和不确定度,为国际标准引进提供了实验数据参考。     

中子反照率个人剂量计

１引言前面的文章〔１〕已对中子个人剂量监测做了较全面的介绍。从发展的观点看，作为记录个人剂量计，热释光／径迹蚀刻（ＴＬＤ／ＴＥＤ）组合剂量计或带辐射体的径迹蚀刻剂量计有着明显的优势。气泡剂量计以其灵敏度高也很具吸引力。但是反照率个人剂量计由于发展比较...     

径迹蚀刻探测器（TED）中子个人剂量计

径迹蚀刻探测器（ＴＥＤ），主要是ＣＲ－３９，作为中子个人剂量计得到了广泛发展和一定范围的应用。本文就ＴＥＤ基本原理，蚀刻和读出技术作了简介，并就ＣＲ－３９作为中子个人剂量计的剂量特性、存在的问题和发展方向进行了较详细的讨论。     

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.