Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation — Fundamentals and application — Part 2: Advanced applications
电离辐射测量用特性限值(决定阈值、探测限值和覆盖间隔限值)的测定.基本原理和应用.第2部分:高级应用
发布日期:
2019-02-13
ISO 11929系列规定了在电离辐射计量学领域中,当执行具有预选时间或计数的计数测量时,用于计算非负电离辐射测量对象的“判定阈值”、“检测极限”和“覆盖间隔的极限”的过程。被测对象来自总计数率和背景计数率以及基于评估模型的其他量。特别地,被测物可以是作为总计数率和背景计数率之差的净计数率,或样品的净活性。它还会受到测量系统校准、样品处理和其他因素的影响。
ISO 11929分为四个部分,涵盖ISO 11929中的基本应用-1、基于本文档中GUM补充1的高级应用、ISO 11929-3中展开方法的应用以及ISO 11929-4中的应用指南。
ISO 11929-1涵盖了电离辐射计量领域中常用的计数测量的基本应用。它仅限于可以根据ISO/IEC指南98-3(JCGM 2008)评估不确定性的应用。ISO 11929-1:20 19的附录A涵盖了具有随机影响的重复计数测量的特殊情况,而ISO 11929-1:20 19的附录B涵盖了线性模拟速率计的测量。
本文件将以前的ISO 11929:2010扩展到根据ISO/IEC指南98-3-1对测量不确定度的评估。它还提出了一些关于计数测量的一般方面和测量中的贝叶斯统计的解释性说明。ISO 11929-3涉及使用展开方法进行测量的评估,如果通过展开方法进行评估,则对光谱多通道测量进行计数,特别是对于α和γ?光谱测量。此外,它还提供了一些关于如何处理相关性和协方差的建议。
ISO 11929-4为ISO 11929的应用提供了指导,简要总结了一般程序,然后给出了广泛的数值示例。关于ISO 11929的统计根源及其当前发展的信息可以在其他地方找到【30,31】。
ISO 11929也类似地适用于任何类型的其他测量,特别是如果涉及类似的评估模型。另外的实际例子可以在例如ISO 18589[1]、ISO 9696[2]、ISO 9697[3]、ISO 9698[4]、ISO 10703[5]、ISO 7503[6]、ISO 28218[7]和ISO 11885[8]中找到。注:根据ISO 119291至ISO 11929-3,可使用名为UncertRadio的代码系统进行计算。uncertradio[27][28]可从https://www.thuenen.de/en/fi/fields-of-activity/marine-environment/coordination-centre-of-radioactivity/uncertradio/免费下载。下载包含一个安装程序安装文件,该文件将所有文件和文件夹复制到用户指定的文件夹中。安装后,必须将信息添加到Windows的路径中,如pop所示?安装过程中打开窗口。可以选择英语,并提供广泛的“帮助”信息。另一个工具是包?计量学’[32],可用于在R中编程。它包含两个R函数?不确定和?分别通过分析或蒙特卡罗方法执行GUM符合不确定性传播的uncertMC。包括输入量的协方差/相关性。在决策阈值和检测限计算的迭代中应用这两个函数显著简化了编程工作。也可以在包含蒙特卡罗插件的电子表格中或在其他商业数学软件中实现ISO 11929的这一部分。
The ISO 11929 series specifies a procedure, in the field of ionizing radiation metrology, for the calculation of the "decision threshold", the "detection limit" and the "limits of the coverage interval" for a non-negative ionizing radiation measurand when counting measurements with preselection of time or counts are carried out. The measurand results from a gross count rate and a background count rate as well as from further quantities on the basis of a model of the evaluation. In particular, the measurand can be the net count rate as the difference of the gross count rate and the background count rate, or the net activity of a sample. It can also be influenced by calibration of the measuring system, by sample treatment and by other factors.
ISO 11929 has been divided into four parts covering elementary applications in ISO 11929-1, advanced applications on the basis of the GUM Supplement 1 in this document, applications to unfolding methods in ISO 11929-3, and guidance to the application in ISO 11929-4.
ISO 11929-1 covers basic applications of counting measurements frequently used in the field of ionizing radiation metrology. It is restricted to applications for which the uncertainties can be evaluated on the basis of the ISO/IEC Guide 98-3 (JCGM 2008). In Annex A of ISO 11929-1:2019 the special case of repeated counting measurements with random influences is covered, while measurements with linear analogous ratemeters are covered in Annex B of ISO 11929-1:2019.
This document extends the former ISO 11929:2010 to the evaluation of measurement uncertainties according to the ISO/IEC Guide 98-3-1. It also presents some explanatory notes regarding general aspects of counting measurements and on Bayesian statistics in measurements.
ISO 11929-3 deals with the evaluation of measurements using unfolding methods and counting spectrometric multi-channel measurements if evaluated by unfolding methods, in particular, for alpha- and gamma?spectrometric measurements. Further, it provides some advice on how to deal with correlations and covariances.
ISO 11929-4 gives guidance to the application of ISO 11929, summarizes shortly the general procedure and then presents a wide range of numerical examples. Information on the statistical roots of ISO 11929 and on its current development may be found elsewhere[30,31].
ISO 11929 also applies analogously to other measurements of any kind especially if a similar model of the evaluation is involved. Further practical examples can be found, for example, in ISO 18589[1], ISO 9696[2], ISO 9697[3], ISO 9698[4], ISO 10703[5], ISO 7503[6], ISO 28218[7], and ISO 11885[8].
NOTE A code system, named UncertRadio, is available for calculations according to ISO 119291 to ISO 11929-3. UncertRadio[27][28] can be downloaded for free from https://www.thuenen.de/en/fi/fields-of-activity/marine-environment/coordination-centre-of-radioactivity/uncertradio/. The download contains a setup installation file which copies all files and folders into a folder specified by the user. After installation one has to add information to the PATH of Windows as indicated by a pop?up window during installation. English language can be chosen and extensive "help" information is available. Another tool is the package?metRology'[32] which is available for programming in R. It contains the two R functions?uncert' and?uncertMC' which perform the GUM conform uncertainty propagation, either analytically or by the Monte Carlo method, respectively. Covariances/correlations of input quantities are included. Applying these two functions within iterations for decision threshold and the detection limit calculations simplifies the programming effort significantly. It is also possible to implement this part of ISO 11929 in a spreadsheet containing a Monte Carlo add-in or into other commercial mathematics software.