天然放射性核素α能谱测量原理

α能谱测量技术广泛应用于环境评价、资源勘查及地质构造勘查等领域。首先分析了天然放射性核素α能谱特性,然后详细论述了α能谱测量原理。根据天然α放射性核素的电学特性,通过增加电场来提高测量灵敏度,并完成了初步实验。最后,探讨了进行α能谱测量的信号调理电路的要求。     

α粒子间接探测技术原理简介

介绍了一种α粒子间接探测技术原理,解决某些场合直接测量α粒子的难题。α粒子在空气中产生的离子数与α粒子的注量和能量之积成正比,通过收集α粒子在空气中产生的电离离子的方法,来间接测量α粒子,根据所测电离电流估算α核素的活度。根据测量原理,设计制作了一套间接测量α粒子的实验装置,并进行了实验验证。结论表明间接α测量技术原理可行,测量结果可靠,对α粒子有较好的响应。     

长程α粒子探测器研究进展北大核心CSCD

α粒子射程短,常规α放射性活度直接测量方法难以测量不规则表面及管道内等区域的α放射性活度。长程α粒子探测器(long-rangeαdetector,LRAD)是目前用于此类区域α放射性污染的有效测量手段之一,被广泛应用于坑洞、核设施管道内等难以近距离测量环境的α放射性活度监测。本文介绍了LRAD的基本原理、发展及现状,并展望了LRAD的应用前景及发展方向。     

α粒子测量仪器现状与发展趋势

综述了可用于α粒子测量的常用α探测器(气体探测器、闪烁探测器和半导体探测器)、特种α探测器(原子核乳胶和固体径迹探测器)、α强度测量仪(闪烁计数仪、α活度测量仪、α表面污染仪和低本底α测量仪)、α能谱测量仪和α磁谱仪的主要性能指标及其现状,并对其发展趋势与应用前景进行了展望.     

用电离室测定α衰变率的校正因素

目前用于测量α衰变率的方法主要有α-γ符合,-π计数,小立体角计数、液体闪 烁计数及电离室等测量装置。这些方法各有其优缺点。电离室作为一种经典而又可靠的设备,早已用于α放射性强度的相对及绝对测量。对于核素(特别是锕系元素核素)的α放射性的能量一般为4—9MeV。电离室对于这种能量范围的α粒子的探测效率是相同的。因此在这种情况下测量,电离室是十分方便和有利的。但对于高准确度的测     

离子收集法测量α粒子技术在α表面污染测量中的应用初探

介绍了离子收集法测量α粒子的原理,初步探讨了这种技术将来在α表面污染测量工作中的应用前景。     

α放射性气溶胶连续测量的本底扣除技术及探测灵敏度研究

为了实现核设施退役现场α气溶胶的实时连续测量,开展了针对各单独核素的天然本底跟踪补偿技术研究,并对连续测量模式下的α气溶胶探测灵敏度进行了研究。通过理论分析及实验研究,实现了α气溶胶实时连续测量过程中天然本底的α能谱向前拖尾部分的影响的自动跟踪补偿,使用该方法对天然本底进行扣除,其扣除率大于90%。使用建立的实时连续测量过程中针对各单独核素的天然本底跟踪补偿技术及气溶胶的分粒度连续取样技术进行了α气溶胶浓度连续测量模式的探测灵敏度研究,当监测时间为25 min,氡子体浓度为100 Bq·m-3时,对α气溶胶浓度连续测量的探测灵敏度为0.02 Bq·m-3。     

金硅面垒型半导体探测器在α能谱测量中的应用研究

针对α能谱测量需要探测器能量分辨率高、性能稳定及探测效率高等要求,选用金硅面垒型半导体探测器进行α能谱测量.论述了金硅面探测器的主要性能指标及影响因素,同时针对探测器输出信号的特点以及α能谱测量要求,从理论上分析了前置放大器的类型及设计时需要注意的事项,并设计了一种实用低噪声电荷灵敏前置放大器.实测α能谱数据表明,性能满足α能谱测量要求.     

^241Am火警源α能谱测量分析系统

按照＾２４１Ａｍ火警源发射的α能谱特点和使用者对α能谱的要求，研究了对这类放射源α能谱的测量分析方法，建立了适合于这种放射源的α能谱的半自动测量分析装置。经过近一年的试运行，证明该方法和新建装置完全能满足生产过程中对＾２４１Ａｍ火警源的α能谱测量和分析、发货前的α能谱质量检验、使用者对源的α能谱验收检验要求，是目前测量分析＾２４１Ａｍ火警源α能谱的一种较好装置。     

氡子体α能谱法测量仪器探测效率的测定

在氡子体α能谱法测量中,一个需要考虑的问题是探测器对不同能量的α粒子是否具有相同的探测效率。本文用^241Am标准源和加拿大Pylon公司的氡子体标准源对ORTEC八通道α谱仪进行了全谱和高、低能量段探测效率的测定,并对两种测量方法存在的误差进行了分析。测量结果表明,两种方法测得全谱探测效率在误差范围内是一致的;在用氡子体源测量谱仪的探测效率时,α能谱由于滤膜的自吸收而存在着峰重叠现象,经重叠因子修正后,仪器对氡子体较高能量的α粒子（7．69 MeV）的探测效率要略大于较低能量的α粒子（6．00 MeV）,且探测效率的差异随滤膜种类的不同而变化。用氡子体标准源对仪器进行刻度更接近于氡子体测量的实际情况。     

氡短寿命子体浓度测量

本文从氡及其子体衰变规律出发，根据取样和测量期间的边界条件解Ｂａｔｅｍａｎ方程，详细推导了总ａ计数法和ａ能谱法测量待测空气中氡短寿命子体浓度的计算公式，编写了计算机程序核对了收集到的部分测量程序的公式；指出了两个已发表公式的错误，进行更正和补充后，列出了相应的ＳＩ单位表示的公式，成功地将计算机技术用于氡子体测量。     

An improved procedure for the determination of apparent strain

An improved procedure for theoretically determining the apparent strain is proposed. Based on the results of an experimental study into the behaviour of high temperature strain gages in a varying thermal environment a theoretical formula is developed. One of the significant features of the proposed formula lies in its ability to predict the apparent strain without actually carrying out the experiment, provided the relevant strain gage material parameters as also the coefficient of thermal expansion of the specimen material are known. A comparison study of the results obtained by using the proposed formula with the experimentally determined results shows excellent agreement. Its application to the development of improved temperature compensated gages is also indicated.     

Mathematical Simulation Procedure of Multicomponent Separating Cascade

A simulation procedure of multicomponent separating cascades is developed. This procedure is applicable and effective in such cases that the cut of mixture of each stage is prescribed and required to be independent of concentration, and the stage separation factors are given as input variables and very large. It can deal with cascades which have multiple feeds and sidestreams. The stage separation factors are allowed to be given as functions of compositions of down streams and up streams. The exact solutions are found out treating all the basic equations simultaneously by use of multi-dimensional Newton-Raphson method.

As an application of this procedure to actual cascade calculations, a computer simulation study is carried out for hydrogen isotope separation system by porous membrane method which consists of two cascades and two catalytic equilibrators. It is proved that the Newton-Raphson iterative calculation proceeds stably under the assumed input and output conditions, and the porous membrane method is worth while to investigate in further studies as one of promising methods for hydrogen isotope separation.     

软X射线喷射冲量的解析计算

基于X射线能量沉积的分配原则,给出了一种脉冲软X射线喷射冲量的解析计算方法,并在“强光一号”加速器上实验测量了软X射线辐照产生的喷射冲量。该解析计算方法的计算结果与BBAY公式计算结果一致,也与实验结果符合较好。本解析计算方法可应用于工程上对X射线喷射冲量的估算。     

核电厂金属疲劳监测过程中环境影响疲劳评价方法研究

轻水反应堆中金属部件的环境影响疲劳寿命（EAF）问题近年来一直是国内外核安全设备研究和监管所关注的重要问题。本文对日本和美国的相应试验研究数据进行了深入分析,对环境影响疲劳修正系数F_en的计算公式进行了分析讨论,总结出不同金属材料F_en计算结果的保守性以及关键影响因素的敏感性。结合我国的实际情况,借助F_en修正计算公式,给出了一种核电厂金属疲劳监测过程中开展环境影响疲劳的评价方法。结果表明：现阶段可基于核电厂监测的真实瞬态数据采用F_en修正公式对环境影响因子进行估算,对于同类型的金属材料,不同试验环境拟合的F_en公式计算结果非常接近,但EAF问题在金属部件疲劳寿命评估过程中不可忽视。     

Radiological Prediction and Monitoring of Tests at the Nuclear Rocket Development Station

The procedure and formula used in the radiological analysis of reactor testing at the Nuclear Rocket Development Station are described. Monitoring methods are discussed and comparison is made between measured dose levels and guide values.     

带有不确定性的多元变量的最小二乘分析方法

在数据空间导出了适用于处理带有不确定性的多元变量的最小二乘公式，并给出了计算实例。     

Transport Theory of Neutron Wave Propagation by Eigenfunction Expansion Method

An eigenfunction expansion method is developed for the neutron wave propagation theory with a cut off cross section. The full and half range orthogonality relations for the eigenfunctions are derived, which are respectively applied to obtain an infinite space solution and the space eigenvalue formula.

The formula is tried on some actual evaluations, and found to reduce considerably the laborious procedure required hitherto. The existence of marked interference phenomena between the discrete and the pseudo modes is demonstrated by numerical calculations performed on the solutions for graphite and beryllium.     

Studying compactibility and uniformity of green molding sand by gamma-ray attenuation

The compactibility and the uniformity of green molding sand have been investigated by the gamma-ray attenuation. A simple measurement formula was established to measure the compactibility and the relative error was analyzed. In order to estimate the uniformity, the γ-ray tomography was used to observe the foreign substances in the dried molding sand samples with a self-designed simple setup. The results indicated that the γ-ray tomography can be considered as an effective means for estimating the uniformity. Furthermore, a feasible detection and control method was developed to improve the procedure of green molding sand production. However, the compactibility measurement should be based on the premise of the uniformity estimation.     

考虑自变量不确定性的曲线拟合方法和程序

给出了考虑自变量不确定性的曲线拟合的最小二乘法公式并编制了程序，给出了计算实例。