荧光玻璃、热释光和光释光探测器性能比较

介绍了荧光玻璃探测器、热释光探测器和光释光探测器基本原理和近期发展,并总结了荧光玻璃、热释光探测器、光释光探测器的优缺点.荧光玻璃最大优点是长期稳定性好和可多次读取.热释光和光释光探测器具有灵敏度高、低探测阈、较好的稳定性和能量响应、环境适应性强等优点.但与LiF:Mg,Cu,P相比,α- Al2O3:C光释光探测器对...     

升温速率对氟化锂热释光探测器灵敏度和探测阈的影响

本文探讨了１－５０℃／ｓ范围内升浊译ＬｉＦ热释光探测器灵敏度和探测阈的影响。实验数据经统计处理后表明ＬｉＦ（Ｍｇ．Ｃｕ,Ｐ）和ＬｉＦ（Ｍｇ,Ｔｉ）－Ｍ在此范围内不同升温速率下的灵敏度和探测阈无差异。     

国产氟化锂片型热释光探测器性能比较研究

本文报道了对常用国产ＬｉＦ（Ｍｇ，Ｃｕ，Ｐ）和ＬｉＦ（Ｍｇ，Ｔｉ）两类片型热释光探测器的６种产品进行剂量学性能比较研究的结果。根据国家标准“个人和环境监测用热释光剂量测量系统”的技术要求和实际需求，比较了这几种探测器的热释发光曲线，相对灵敏度，探测阈，线性度，光子能量响应，一批的均匀性，重复性和稳定性等剂量学特性。文中还对ＴＬ探测器应用中的有关问题作了讨论。     

RGD6型热释光仪研制

本文介绍了新研制的RGD6型热释光仪的基本特点、主要技术性能和工作原理,详细描述了其特有的连续自动测量功能.试验结果表明,RGD6型热释光仪在功能设计、测量灵敏度及数据分散性等方面均有明显提高,满足了热释光测量的性能要求.     

放射性碘连续监测系统判断阈和探测限的确定

结合中国辐射防护研究院研制的PIG连续监测系统中对放射性碘的采样、测量和数据分析方法,按ISO规定的判断阈和探测限的计算原则确定了PIG连续监测系统放射性碘监测部分的判断阈和探测限.     

热释光LiF(Mg,Cu,P)探测器对宇宙射线的响应

在北京市密云水库水面对国内环境累积剂量测量中使用较多的GR-200A型、CTLDM000型和TLD2000型热释光LiF(Mg,Cu,P)探测器对宇宙射线的响应进行了实验测量,得出了三种热释光探测器相对于高压电离室的宇宙射线响应因子分别为0.845和0.877和0.839.     

热释光粉末分装器

引言热释光剂量测量方法是近十几年来迅速发展起来的一种新型剂量监测技术。由于它具有许多优点,在辐射防护、放射医学与放射生物学、地质、考古等方面都备受重视,并得到广泛应用。在热释光测量技术中,粉末状热释光材料具有分散性小,测量中不需要进行挑选等优点。因此,在热释光测量工作中,粉末状热释光材料至今仍是人们喜欢的重要探测元件。但是,它与成形的热释光元件相比,使用粉末也有某些不便之处。例如,为保证剂量测定的精度要求对成千上万份热释光粉末要准确称量。     

基于EM9000工控机的热释光仪软件设计

本文介绍了EM9000工控机的性能特点,描述了基于EM9000工控机的热释光仪控制软件的功能设计及系统模块构成;阐述了发光曲线实时变换及显示难点的解决办法.实验结果表明,该系统测量效率和探测灵敏度较高,存储、读取数据方便可靠.     

简易热电偶焊接器

热释光技术已广泛地用于辐射剂量监测。由于热释光探测元件有方片、圆片、圆棒及粉末等形式,应用不同测量元件需更换不同的测量盘;此外,测量盘用久变黑也需更换。在更换的过程中,极易碰断热电偶丝。本文介绍一种热电偶焊接器和焊接方法,较满意地解决了这个问题。     

LiF(Mg,Cu,P)热释光探测器测量、退火方式的确定

实验研究了BR－1000A型LiF(Mg,Cu,P)热释光探测器的测量和退火方式对剂量测量的影响。结果表明，当测量和退火方式分别在热释光探测器两个不同表面下进行时，其分散性将比测量和退火在同一表面下进行时增大，使测量精度下降，所以在高精度要求的测量下，应使测量和退火面保持一致，热释光探测器受灰尘或手触摸等污染后，对其读出值和测量精度有一定影响，其影响大小和污染程度有关。     

Identification of radiation treatment of wheat （Triticum aestivum. L）and rice （Oryza sativa. L） samples using thermoluminescence of contaminating minerals

Food irradiation is gaining popularity worldwide and this technology is important to improve quality and reduce the post harvest losses of food. Because of the rapid commercialization of irradiated foods throughout the world, compliance of different regulations relating to use of technology in different countries and demand of consumers for clear labelling of irradiated foods, there is need for the development of analytical methods to detect radiation treatment of food. Among several methods studied so far, thermoluminescence （TL） is an important method that can be used to find out the irradiation history of food that contain even a very minute amount of dust particles. In this study, the irradiated and unirradiated wheat and rice samples were analyzed using the TL method. The samples were purchased from the local market of Peshawar and irradiated to radiation doses of 0.5 and 1.0 kGy using Co-60 gamma irradiator at the Nuclear Institute for Food and Agriculture （NIFA）, Peshawar. The mineral contaminants were isolated by jet water, ultrasonic treatment, and density gradient. TL glow curves of the isolated minerals from irradiated and unirradiated samples were recorded between the temperature ranges of 50-500℃ using a TL reader. Generally, the glow curves for irradiated samples showed much higher TL intensities （TL1） than the unirradiated samples. The results were normalized by rerradiation of mineral samples to gamma-ray dose of 1.0 kGy followed by determination of the second glow curves （TL2）. The ratio of the area of first glow curve to that of second glow curve （TL1/TL2） was calculated for selected temperature intervals and compared with the recommended values for unirradiated and irradiated samples. Finally, the shapes of the glow curves for irradiated and unirradiated samples were also analyzed. On the basis of these results （comparison of TL-intensities, TL1/TL2 ratios and shapes of the glow curves）, all the irradiated and unirradiated samples of wheat and rice were unequivocally identified.     

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。     

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.     

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.     

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.     

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.     

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.