镉比R_（Cd）测量数据处理的精确化

AN IMPROVED DATA PROCESSING METHOD FOR CADMIUM RATIO(R_(Cd))MEASUREMENTS

镉比Ｒ＿（Ｃｄ）测量是常用的堆内中子测量。有关它的数据处理的精确化问题，主要涉及以下４点。１）建立堆内中子通量密度谱一般表达式。２）导出以标准热中子平均活化截面和标准共振积分为基础的Ｒ＿（Ｃｄ）公式，并定义有关参量，包括热能区和中能区的参量。后者有镉切割能Ｅ＿（Ｃｄ），中能对镉上中子反应率比Ｆ＿（Ｃｄ），镉上自屏因子Ｇ′＿ｒ和引导标准谱修正因子Ｇ″＿ｒ。３）以金片为例，计算参量对变量的依赖关系。选用必要的图表说明它们的特性，并为手算处理提供最低限度的实用数据。４）讨论Ｒ＿（Ｃｄ）测量的适用范围，包括最佳区和适用区。

R_(Cd) measurement is a commonly used reactor neutron flux dinsity measurement.The objectof this work is to discuss the improvement of its data proceessing.The main content consists of 4parts.1)To establish the general neutron flux dinsity spectrum expression in thermal neutronreactors.2)To drive R_(Cd) formula based on standard thermal average activation cross-section andresonance integral and to define all related parameters or factors including these in thermal energyregion and these in intermediate energy region.The later are cadmium cut-off energy E_(Cd) ratio ofinterinediate reaction rate to supper cadmium F_(Cd) super cadmium self-shielding factor G′_r and in-duced standard flux dinsity spectrum correction factor G″_r.They all are the function of multiplevariables.3)Using Au foil as an example to calculate the dependence of parameters or factors onvariables, to choice necessary figures and tables in order to show behaviors of them and to providethe necessary data for the practical data processing by hand.4) To discuss the limitation of avail-able region in R_(Cd) measurement.In this region the optimum and suitable range can be divided.Itis noticed that the Co or Mn foil has a much wider available region among such as Au,In,Mnand Co, the commonly used R_(Cd) measurement material detector foils.