国产辐射变色染料氰化物溶液剂量计的γ剂量测量

目前,国际上应用最广的两种辐射变色染料是六羟乙基副品红氰化物(hexahydroxyethylpararosaniline cyanide,HPR-CN)及副品红氰化物(pararosaniline cyanide,PR-CN)。本工作是以自行合成的HPR-CN和PR-CN为剂量计,与美国Far West Technology Inc.生产的HPR-     

用于热核同位旋效应研究的BGO探测器阵列

报道了35MeV/u 36Ar 112,124Sn反应中用于中等质量碎片(IMF)(3≤Z≤5)关联函数测量的△E(Si) E(BGO)望远镜阵列的测试结果.实验表明该探测器阵列的几何安排有利于提高小角关联测量中的动量分辨,可用于IMF发射时标的同位旋依赖性的研究.     

用于热核同位旋效应研究的高质量分辨望远镜探测器

描述了一个用于热核同位旋效应研究的高质量分辨带电粒子望远镜探测器。望远镜由三叠层探测器组成。其中前两片是全耗尽硅半导体△Ｅ探测器,后一片是锂漂移硅探测器。其厚度分别为：３５０、５００、３５００μｍ,此探测器的主要特点是：具有高能量分辨、高质量分辨、大能量范围,可对直到硫的粒子进行同位素鉴别,能较好地用于热核同位旋效应研究。     

葡萄糖溶液化学剂量计特性的研究

辐照后的葡萄糖碱性溶液在267nm 处有一特征吸收峰。当葡萄糖溶液浓度和碳酸氢钠溶液的浓度都为0.1M,受照剂量在1×10~5—1×10~7rad 范围时,吸光度峰值与吸收剂量呈线性。温度从5℃至35℃时,温度系数为 0.9％/℃。吸收峰值有衰退,但在低温下衰退大为减慢。本文还讨论了葡萄糖溶液和碳酸氢钠溶液的浓度及其它因素对辐照响应的影响。     

高灵敏度的硫酸亚铁-苯甲酸-二甲酚橙化学剂量计

实验研究了硫酸亚铁-苯甲酸-二甲酚橙化学剂量计体系的基本性质。测定该体系的 G(Fe~(3 ))是61.2±0.6。发现当 Fe~(3 )浓度增大时,峰红移。如果不管峰移,而只取最高峰的光密度值,那么光密度值与吸收剂量之间的线性关系上限可达4000rad。     

“兆吨到兆瓦”计划已将225t武器级铀转化成燃料

【美国《核新闻》2004年11月刊报道】 美国铀浓缩公司(USEC)2004年10月5日宣布,“兆吨到兆瓦”计划已将俄罗斯的 225 t武器级铀(相当于9000枚核弹头)转化成可供美国核电机组使用的燃料。 “兆吨到兆瓦”计划于1994年启动。按照该计划,到2013年计划结束时,美国USEC和俄罗斯Tenex公司要把500 t武器级铀(相当于2万枚核弹头)转化成燃料。目前美国已有100多台核电机组在使用来自“兆吨到兆瓦”计划的核燃料。美国有近10%的电力来自“兆吨到兆瓦”计划。 USEC公司每年购买将近4.5亿美元的燃料,迄今用于购买燃料的总金额已超过35亿美元,据报…     

用于防护级照射量实验室标准的薄壁球形电离室

本文介绍了一种可作为防护级照射量实验室标准的塑料薄壁球形电离室的设计和主要性能。该电离室容积为100cm~3;本底电流不大于1×10~(15)A;在33keV—1.25MeV 能区内的能量响应(以~(60)Coγ射线的响应归1)<±5%;在上述能区内,当照射量率为10mR/h时,校准因子的总不确定度(一倍标准差)估计为±0.9%,在近一年内的长期稳定性<±1.2%。该电离室于1987年 IAEA 关于次级标准实验室校准程序亚太地区比对研讨会期间与 IAEA 剂量实验室比对,在上述能区内与本实验室校准结果在1.2%内相符。     

兆吨换兆瓦计划已消除可用于制造1．5万枚核弹头的高浓铀

【美国铀浓缩公司网站2009年9月23日报道】美国铀浓缩公司（USEC）2009年9月23日宣布,兆吨换兆瓦计划目前已完成了75％的计划目标,即消除了可用于制造1．5万枚核弹头的高浓铀,预计在2013年年底之前将完成全部计划目标,即消除可用于制造2万枚核弹头的高浓铀。     

分光光度法测量水中磷酸盐含量的不确定度评定

针对核电厂常用的分光光度法测量水中磷酸盐的方法,详细描述其实验过程各步骤引入的不确定度分量,并对测量不确定度进行评定,最终得出测量报告与扩展不确定度。结果表明,影响核电厂磷酸盐测量不确定度的主要来源为标准曲线线性拟合以及配制磷酸盐工作标准系列溶液的过程,其次来自样品稀释过程。该研究为提高分光光度法测量水中磷酸盐的分析准确度提供了理论支撑与依据。     

水峰抑制(WEFT)技术在~1H NMR中研究糖类化合物的变旋现象

在FX-100型核磁共振仪器上,将WEFT技术用于观察糖类化合物六元环结构中与氧原子直接联结的C_1上的α、β构型质子峰高的变化,从中获取糖类化合物在水溶液中的变旋行为信息,得到α、β构型的平衡时间,以及最后平衡浓度α、β各占的百分比;通过变旋的动力学过程,跟踪了一般~1H NMR无法观察到的C_2位质子峰的化学位移。     

DTPA作为~(90)Sr/~(90)Y发生器淋洗剂的研究

测定了在不同浓度和不同pH的二三胺五乙酸(DTPA)介质中,Sr~(2+)、Y~(3+)离子在国产732型阳离子交换树脂上的分配系数,并进行了~(90)Sr-~(90)Y柱分离,据此选择3m mol/L、pH为5.5的DTPA作为~(90)Sr/~(90)Y发生器的淋洗剂。试制的0.86GBq发生器经1年29次淋洗测定,其~(90)Sr漏穿率为(1.7±0.5)×10~(-7)。结果表明,DTPA是~(90)Sr/~(90)Y发生器的一种优良的新型淋洗剂,以DTPA作为淋洗剂的发生器可提供用于放射免疫治疗的高纯~(90)Y。     

The effect of crystal textures on the anodic oxidization of zirconium in a boiling nitric acid solution

The effects of crystal textures and the potentials in the anodic oxidation of zirconium in a boiling nitric acid solution were investigated to study the stress corrosion cracking of zirconium in nitric acid solutions. The test specimen was machined such that the specimen surface was parallel to the rolling surface, arranged with a (0002) crystal texture. The potentials applied for the anodic oxidation of zirconium were set at 1.2, 1.4, and 1.5 V against a saturated KCl–Ag/AgCl electrode (SSE) in boiling 6 M HNO₃. The growth of the zirconium oxide film dramatically changed depending on the applied potential at a closed depassivation potential (1.47 V vs. SSE in this study). At 1.5 V, the zirconium oxide film rapidly grows, and its growth exhibits cyclic oxidation kinetics in accordance with a nearly cubic rate law. The zirconium oxide film grows according to the quantity of electric charge and the growth rate does not depend on the crystal texture in the pretransition region before the cyclic oxidation kinetics. However, the growth and cracking under the thick oxide film depend on the crystal texture in the transition region. On the normal direction side, the oxide film thickness decreases on average since some areas of the thick oxide film are separated from the specimen surface owing to the cracks in the thick oxide. On the rolling direction (RD) side, no cracks in the thick oxide film are observed, but cracks are found under the thick oxide film, which deeply propagate in metal matrix along the RD without an external stress. The cracks under the thick oxide film propagate to the center of the oxide layer. The crystal orientation relationship between the oxide layer and the zirconium matrix is (0002)_Zr//(111)_ZrO2, and the cracks in the oxide layer propagate in the (0002)_Zr plane in the zirconium matrix. The oxide layer consists of string-like zirconium oxide and zirconium hydride. The string-like zirconium oxide contains orthorhombic ZrO₂ in addition to monoclinic ZrO₂. It is not well known why the cracks propagate along the (0002)_Zr plane under the thick oxide film. As one assumption for the mechanism of crack initiation and propagation without an external stress, it is considered that the oxidizing zirconium hydrides precipitated in the (0002)_Zr plane near the interface of the thick oxide film and the matrix. Then, the phase transformation from orthorhombic ZrO₂ to monoclinic ZrO₂ in the oxide layer causes the crack propagation in the (0002) plane.     

The Singular Value Decomposition as a Tool of Investigating Central MHD Instabilities in the HL-1M Tokamak

A variety of strong MHD instabilities are always resulted from MHD activity of Tokamak plasmas. Central MHD instabilities can be observed with pinhole cameras to record soft x-ray (SXR) emission from the plasma along many chords with a high temporal resolution. The investigation of MHD instabilities often necessitates an analysis on spatial-temporal signals. The method of Singular Value Decomposition (SVD) can split such signals into orthogonal spatial and temporal vectors, By this means, the repetition time and the characteristic radius of various MHD phenomena such as sawteeth and snake-like perturbation can be obtained. Moreover, the (1,1) MHD mode is analyzed in great detail by SVD and used to determine the radius of the q = 1 surface.     

图像仿真在数字辐射成像系统指标估算中的应用

通过计算机模拟的方法改进了^60Co集装箱检测系统的指标估算的方法，结果CI和IQI指标估算值与实测值较好地吻合。     

~6Li第二激发态中子质子晕结构的首次实验证实

利用北京HI 13串列加速器次级束流线产生的能量为4.17AMeV的6He束对电荷交换反应1H(6He,6Li)n的角分布进行了逆运动学的测量。实验结果与微观计算的比较表明:6Li第二激发态和6He的基态都具有晕结构。本工作首次证实了K.Arai等1995年提出的6Li第二激发态具有中子 质子晕结构的理论预言。     

核素淋巴显像在血液病诊断中的临床应用

报道了对７８例临床疑诊恶性淋巴瘤及白血病病人核素淋巴显像结果的分析。以评价淋巴显像在血液病诊断中的应用。经病理证实恶性淋巴瘤３０例,非恶性淋巴瘤２４例,核素淋巴显像诊断恶性淋巴瘤的灵敏度为８３．３％,特异性为６２．５％;与ＣＴ及Ｂ超相比,临床符合率分别为８３．３％、６６．７％和２２．２％;经骨髓穿刺证实白血病９例,非白血病１５例,核素显像诊断白血病的灵敏度为８８．９％,特异性为５３．３％;与ＣＴ相     

剩余气体束流剖面探测系统首次在线实验

介绍了以微通道板和电阻阳极所构成的位置灵敏探测器为基础的剩余气体束流剖面探测系统的工作原理和系统结构,描述了首次在线实验情况,证明了利用剩余气体束流剖面探测系统进行非拦截束流诊断的方法是可行的。     

The treatment of resonance interference effects in the subgroup method

This paper describes the development of a method to treat resonance interference effects within the framework of the subgroup method. The new procedure provides for the treatment of multiple resonance absorbers in which the subgroup weights are determined using a least squares technique and based on the cross sections generated from a mixture of multiple resonance isotopes and a suitably wide range of background cross sections. The method was implemented in the Method of Characteristics code DeCART and validated using MCNP. In order to implement the new method, the NJOY code was used for the calculation of neutron spectra and resonance parameters in for each representative LWR mixture. The resonance parameters, lambda, of the scattering isotopes are computed not just with U-238 as the resonance isotope as in previous applications of the subgroup method, but also with U-235 as resonance isotope for the energy groups in which U-238 has no significant resonances. After developing a procedure for generating lambda factors for scattering isotopes, a method is then described for generating subgroup parameters in a homogeneous system. Again NJOY is used for resonance calculations of a set of mixtures for each resonance isotope at each selected temperature. The group average cross sections instead of the resonance integrals of these mixtures are used to generate subgroup parameters using an optimization algorithm. The generated library is then verified by comparing the solution from DeCART with the solution from MCNP. The method is then extended to a heterogeneous system. The code RMET21 is used for transport calculations for the heterogeneous system. The interference effect from the most important resonance isotopes is treated by generating subgroup weights with resonance cross sections for the cases with two resonance isotopes. The results indicate that the subgroup method can accurately represent resonance interference effects within the framework of the subgroup method.     

NaI(Tl)γ谱仪测量数据的计算机处理方法

本文介绍了使用NaI(T1)γ谱线在铅室内分析环境土壤样品和就地γ辐射谱测量的刻度方法,以及专用微机解谱程序的功能和使用方法。