透射式特征X射线测厚仪研制

论述了透射式特征X射线测厚原理,并对样机的硬件组成特征X射线发生装置、X射线探测器、数据处理器和监控软件进行了介绍.通过对测厚样机的实验测试,结果显示测量较薄物质时测厚仪反应灵敏,测量精度较高,相对误差在±5%以内,达到设计要求.     

准单色X射线机替代~(241)Am放射源的测厚应用研究

应用自制的能量50~60 keV的准单色X射线机替代~(241)Am低能光子源(1.11×10~9 Bq)应用于BS-03测厚仪进行测厚研究,分别测试了BS-03测厚仪输出电流范围,测试X射线在钢板、铝板、有机玻璃的衰减规律以及准单色X射线机稳定性,结果表明,准单色X射线机可以替代~(241)Am放射源用于BS-03测厚仪。     

743-1型γ闪烁测厚仪

我们研制了γ闪烁测厚仪。其测量范围0～3.00mm,误差≤±0.03mm。一年多来现场运行试验证明仪器性能良好,满足了使用单位的要求。 一、仪器 γ闪烁测厚仪的原理是基于被测材料对射线的吸收作用。图1为仪器的示意图。选用~(241)Am作γ放射源,强度为22mCi,能量60keV,半衰期458年。源固定在C型支架下端,由3mm厚的铜、8mm厚的钢做生物屏蔽层。     

基本参数法X射线荧光测厚

本文简要介绍了用放射性核素的非单能初级辐射,非破坏地绝对测量极薄层厚度的X射线荧光测厚技术。测量薄层厚度的精确度好于1.1％。与空气等效法α测厚仪的测量结果对照,相对偏差小于3.8％。     

Scs—35型β射线测厚仪

在纸张、塑料薄膜、橡胶或金属薄膜生产过程中,需要不断地监测其厚度并加以控 制,以保证产品质量及节省原材料。由于产品在高速运动,接触式测厚仪难以工作,而电磁式测厚仪又受材质影响较大使测量精度不高。射线测厚仪具有非接触式特点,其中吸收式测厚仪受材质影响较小,是在线测量的理想工具。     

薄膜样品中10B原子核数的实验测量

采用北京大学4.5 MV静电加速器D(d,n)反应产生快中子,通过厚石蜡对中子进行慢化.以6LiF薄膜为标准样品(其中6Li原子核数目已知),使用背对背双屏栅电离室作为带电粒子探测器,同时探测热中子与6Li以及热中子与10B反应产生的t和α粒子.采用相对测量法,得到了待测薄膜样品中10B的原子核数.     

压水堆核电机组二回路给水系统弯头减薄原因分析

2012年3月,某核电厂大修期间对二回路部分管线进行了现场壁厚测量,发现电动主给水泵系统弯头存在壁厚减薄现象。文章对其中的一根弯头在实验室进行了失效分析。利用超声波测厚仪在实验室对换下的弯头进行壁厚测厚并利用等离子光谱发生仪等设备及分析手段对异常减薄部位和减薄一般部位进行了分析研究。结果表明管壁异常减薄是由于流动加速腐蚀（FAC）引起的。最后,根据分析结果,结合国内外的最新研究进展,对管道的管理及变更提出了建议。     

LabWindows/CVI在涂镀层测厚系统中的应用

针对目前涂镀层测厚系统存在的问题,由于虚拟仪器具有传统智能仪器无法比拟的优势,论文提出了基于虚拟仪器涂镀层测厚数据采集系统的设计思想.简要对涂镀层测厚系统进行了硬件设计,主要讨论以微控制器(ARM)为核心的涂镀层测厚系统的设计.特别讨论虚拟仪器的数据采集系统的设计.通过虚拟仪器能够实现对工作现场生产过程的实时监控、数据传输、实时处理、厚度曲线显示.该系统较好完成了涂镀层厚度中重要参数的实时全程控制,并且具有显示直观、反应迅速,性价比高等特点,因此具有一定的使用价值.     

竖壁降液膜流动纵向及水平发展规律研究

采用高频率电容式测厚仪测量并分析了降液膜膜厚和波动的统计规律,得到了降液膜沿竖直大平板流动平均膜厚经验关系式,发现了液膜流动的横向扩展和纵向发展规律。结果表明,降膜在竖直发展2.6 m后可能已基本充分发展。     

测厚电离室研制

一、引言放射性测厚仪中使用的传感器是具有高稳定性和高可靠性的电离室,测厚常用的电离室有空气式β电离室,充气式β,γ和X射线电离室等。它们分别可以测量工业上常见的各种厚度的纸张、塑料薄膜、有色金属及铝、钢等板材的厚度。我们主要研制了具有典型应用价值的三种类型的测厚用电离室,它们分别是dLS-X-1型的高效率X射线电离室,dLS-β-1型空气式β电离室,dLS-β-2型充Ar式β电离室。在研制工作中,对三种类型电离室的制作工艺及性能进行了研究。     

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.     

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.     

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.     

Improvement of carbon fiber surface properties using electron beam irradiation

Carbon fiber-reinforced advance composites have been used for structural applications,mainly on account of their mechanical properties.The main factor for a good mechanical performance of carbon fiber-reinforced com- posite is the interfacial interaction between its components,which are carbon fiber and polymeric matrix.The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite.EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests.Experimental results showed that EB irradiation improved the ten- sile strength of carbon fiber samples.The maximum value in tensile strength was reached using doses of about 250 kGy.After breakage,the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated car- bon fibers were evaluated.SEM micrographs showed modifications on the carbon fiber surface.     

Gamma-ray attenuation technique for measuring void fraction in horizontal gas-liquid two-phase flow

The measurement of void fraction is of importance to the oil industry and chemical industry. In this article, the principle and mathematical method of determining the void fraction of horizontal gas-liquid flow by using a single-energy γ-ray system is described. The γ-ray source is the radioactive isotope of 241Am with γ-ray energy of 59.5 keV. The time-averaged value of the void fraction in a 50.0-mm i.d. transparent horizontal pipeline is measured under various combinations of the liquid flow and gas flow. It is found that increasing the gas flow rate at a fixed liquid flow rate would increase the void fraction. Test data are compared with the predictions of the correlations and a good agreement is found. The result shows that the designed γ-ray system can be used for measuring the void fraction in a horizontal gas-liquid two-phase flow with high accuracy.     

Preparation and adsorption behavior for metal ions and humic acid of chitosan derivatives crosslinked by irradiation

This article deals with the determination of the adsorption properties of metal ions and humic acid in water on crosslinked chitosan derivatives （carboxymethylchitosan） which were formed using the irradiation technique without any additives. The solubility test of these crosslinked materials were investigated in acidic, alkaline media, distilled water, and certain organic solvents. Scanning electron microscopic （SEM） images showed that the crosslinked chitosan derivatives possessed a porous morphological structure. Charged characteristic analyses demon- strated typically pH-dependent properties of the crosslinked materials. The adsorption studies were carried out by the batch method at room temperature. Adsorption of heavy metal ions （such as Cu^2＋, Cd^2＋） and humic acid onto crosslinked samples was found to be strongly pH-dependent. Adsorption kinetic studies indicated the rapid removal of metal ions, and humic acid from the aqueous solutions. Moreover, isothermal adsorption data revealed that Cu^2＋, Cd^2＋, and humic acid were removed by these crosslinked materials with high efficiency. Adsorption isothermal data were interpreted well by the Langmuir equation. These crosslinked carboxymethylated chitosan derivatives indicate favorable adsorption of metal ions and humic acid.     

Non-FDG PET imaging of brain tumors

Due to relatively high uptake of glucose in the brain cortex, the use of FDG PET imaging is greatly limited in brain tumor imaging, especially for low-grade gliomas and some metastatic tumours. More and more tracers with higher specificity were developed lately for brain tumor imaging. There are 3 main types of non-FDG PET tracers： amino acid tracers, choline tracers and nucleic acid tracers. These tracers are now widely applied in many aspects of brain tumor imaging. This article summarized the general use of non-FDG PET in different aspects of brain tumor imaging.     

Radioactivity levels in soil of salt field area,Kelambakkam,Tamilnadu,India

Soil samples in and around salt field area have been analyzed for natural radioactivity concentration using gamma ray spectrometer.The activity concentration for ~(232)Th,~(238)U and ~(40)K are ranged from 27.88 to 45.27 Bq/kg, from BDL to 13.30 Bq/kg,and from 135.54 to 381.28 Bq/kg,respectively.The measured activity concentrations for these radionuclides were compared with world average activity of soil.The average activity concentration of ~(232)Th in the present study is 1.19 times higher than world median value while the activity of ~(238)U and ~(40)K is found to be lower. The absorbed dose rates due to these radionuclides were calculated.The average absorbed gamma dose rate due to the presence of ~(232)Th,~(238)U and ~(40)K in soil samples is 36.99 nGy·h~(-1).These results indicate no radiological anomaly. The data presented in this study will serve as a base line survey for primordial radionuclides concentration in the study area.     

Recovery of Hydrogen Isotopes by Pd-coated ZrNi from Inert Gas Atmosphere Containing Impurities

Effect of Pd coating on recovery of hydrogen isotopes from inert gas atmosphere was investigated for intermetallic compounds ZrNi. Powder of ZrNi was coated with Pd by electroless plating. Subsequent annealing at 1,073 K led to the formation of ZrPd at the powder surface. The durability in deuterium recovery from Ar gas was examined for the bare and the Pd-coated powders at temperatures from 373 to 573 K as well as the kinetics of deuterium absorption and desorption. The absorption and desorption of deuterium obeyed the first and the second order kinetics, respectively. The ZrPd layer on ZrNi did not alter the absorption and the desorption kinetics. The deuterium recovery by the bare powder was degraded with time owing to oxidation of powder surfaces by impurities contained in the Ar gas. The durability in deuterium recovery was markedly improved by Pd coating, and no significant degradation was observed for the Pd-coated specimen at 573 K. This difference in the durability was ascribed to the difference in the oxidation behavior between ZrNi and ZrPd. It was concluded that Pd coating significantly improves the applicability of ZrNi to tritium recovery in blanket systems.     

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.