1、ISO/ASTM 51707:2005(E)ISO/ASTM 51707 2015(E)An American National StandardStandard Guide forEstimating Uncertainties Estimation of MeasurementUncertainty in Dosimetry for Radiation Processing1This standard is issued under the fixed designation ISO/ASTM 51707; the number immediately following the desi
2、gnation indicates theyear of original adoption or, in the case of revision, the year of last revision.1. Scope1.1 This standard provides guidance on the use of concepts described in the JCGM Evaluation of Measurement Data Guideto the Expression of Uncertainty in Measurement (GUM) to estimate the unc
3、ertainties in the measurement of absorbed dose inradiation processing.1.2 This guide defines possible sources of uncertainty in dosimetry performed in gamma, X-ray (bremsstrahlung), and electronirradiation facilities and offers procedures for estimating the resulting magnitude of the uncertainties i
4、n the measurement ofabsorbed dose using a dosimetry system. Basic concepts of measurement, estimate of the measured value of a quantity, “truevalue”, error, and uncertainty are defined and discussed. Components of uncertainty are discussed and methods are given forMethods are given for identifying,
5、evaluating and estimating their values. How these contribute to the standard uncertainty in thereported values of absorbed dose are considered and methods are given for calculating the combined standard uncertainty and anestimate of expanded (overall) uncertainty. The methodology for evaluating comp
6、onents of uncertainty follows ISO procedures(seethe components of measurement uncertainty associated with the use 2.3). The traditional concepts of precision and bias are notused in this document. Examples are given in five annexes.of dosimetry systems and for calculating combined standardmeasuremen
7、t uncertainty and expanded (overall) uncertainty of dose measurements based on the GUM methodology.1.3 Examples are given on how to develop a measurement uncertainty budget and a statement of uncertainty.1.4 This document is one of a set of standards that provides recommendations for properly implem
8、enting dosimetry in radiationprocessing, and provides guidance for achieving compliance with the requirements of ISO/ASTM 52628 related to the evaluationand documentation of the uncertainties associated with measurements made with a dosimetry system. It is intended to be read inconjunction with ISO/
9、ASTM 52628, ISO/ASTM 51261 and ISO/ASTM 52701.1.5 This guide assumes a working knowledge of statistics. Several statistical texts are included in the referencesdoes not addressthe establishment (of1-4). process specifications or conformity assessment.1.6 This standard does not purport to address all
10、 of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced documents2.1 ASTM Standards:2E170 Terminology Relati
11、ng to Radiation Measurements and DosimetryE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE178 Practice for Dealing With Outlying ObservationsE456 Terminology Relating to Quality and StatisticsE876 Practice for Use of Statistics in the Evaluation of Spectrometric Data (With
12、drawn 2003)41 This guide is under the jurisdiction ofASTM Committee E61 on Radiation Processing and is the direct responsibility of Subcommittee E61.01 on Dosimetry, and is alsounder the jurisdiction of ISO/TC 85/WG 3.Current edition approved byASTM June 1, 2004. Sept. 8, 2014. Published May 15, 200
13、5. February 2015. Originally published asASTM E 170795. Last previousASTMedition E 1707951. ASTM E 1707951 was adopted by ISO in 1998 with the intermediate designation ISO 15572:1998(E). The present International Standard ISO/ASTM51707:2005(E)51707:2015(E) is a major revision of the last previous ed
14、ition ISO/ASTM 51707:2002(E),51707:2005(E), which replaced ISO 15572.ISO/ASTM51707:2002(E).2 The boldface numbers in parentheses refer to the bibliography at the end of this guide.2 For referenced ASTM and ISO/ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at
15、serviceastm.org. For Annual Bookof ASTM Standards volume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous versi
16、on. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document. ISO/ASTM International 201
17、5 All rights reserved1E1249 Practice for Minimizing Dosimetry Errors in Radiation Hardness Testing of Silicon Electronic Devices Using Co-60Sources2.2 ISO/ASTM Standards:251204 Practice for Dosimetry in Gamma Irradiation Facilities for Food Processing51205 Practice for Use of a Ceric-Cerous Sulfate
18、Dosimetry System51261 GuidePractice for Selection and Calibration of Routine Dosimetry Systems for Radiation Processing51608 Practice for Dosimetry in an X-Ray (Bremsstrahlung) Facility for Radiation Processing5127551649 Practice for Use of a Radiochromic Film Dosimetry SystemDosimetry in an Electro
19、n Beam Facility for RadiationProcessing at Energies Between 300 keV and 25 MeV5140051702 Practice for Characterization and Performance of a High-Dose Radiation Dosimetry Calibration LaboratoryDo-simetry in a Gamma Facility for Radiation Processing5143152628 Practice for Dosimetry in Electron Beam an
20、d X-ray (Bremsstrahlung) Irradiation Facilities for Food RadiationProcessing52701 Guide for Performance Characterization of Dosimeters and Dosimetry systems for Use in Radiation Processing2.3 ISO Documents:ISO 11137-1 Sterilization of Health Care Products Radiation Requirements for Development,Valid
21、ation and Routine Controlof a Sterilization Process3ISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories42.4 ISO Documents:Joint Committee for Guides in Metrology (JCGM) Reports:ISO, 1995, ISBN 92-67-10188-9JCGM 100:2008, GUM 1995, with minor corrections, Eva
22、luation of measurement data Guideto the Expression of Uncertainty in Measurement5ISO 11137JCGM 200:2008, VIM, Sterilization of Health Care Products-Requirements for Validation and Routine Control-Radiation SterilizationInternational vocabulary of metrology Basis and general concepts and associated t
23、erms62.5 ICRU Reports:7ICRU Report 14 Radiation Dosimetry: X Rays and Gamma Rays with Maximum Photon Energies Between 0.6 and 50 MeVICRU Report 17 Radiation Dosimetry: X Rays Generated at Potentials of 5 to 150 kVICRU Report 3480 The Dosimetry of Pulsed RadiationDosimetry Systems for Use in Radiatio
24、n ProcessingICRU Report 35 Radiation Dosimetry: Electron Beams with Energies Between 1 and 50 MeVICRU Report 37 Stopping Powers for Electrons and PositronsICRU Report 6085a Fundamental Quantities and Units for Ionizing Radiation3. Terminology3.1 Definitions:NOTE 1For definitions quoted here from VIM
25、, only the text of the definition is kept here. Any NOTES or EXAMPLES are not included. They canbe reviewed by referring to VIM (JCGM 200:2008).3.2 Definitions:3.2.1 approved laboratorylaboratory that is a recognized national metrology institute; or has been formally accredited toISO/IEC 17025; or h
26、as a quality system consistent with the requirements of ISO/IEC 17025.3.2.1.1 DiscussionA recognized national metrology institute or other calibration laboratory accredited to ISO/IEC 17025 should be used forirradiation of dosimeters or dose measurements for calibration in order to ensure traceabili
27、ty to a national or international standard.A calibration certificate provided by a laboratory not having formal recognition or accreditation will not necessarily be proof oftraceability to a national or international standard.3.2.2 absorbed dose, Darithmetic mean, average GUM, C.2.19quantity of ioni
28、zing radiation energy imparted per unitmass of a specified material. The SI unit of absorbed dose is the gray (Gy) where 1 gray is equivalent to the absorption of 1 jouleper kilogram of the specified material (1 Gy = 1 J/kg). The mathematical relationship is the quotient of dsum of values dividedby
29、dm, where d is the mean energy imparted by ionizing radiation to matter of mass dthe number of values:m (see ICRU 60).3 The last approved version of this historical standard is referenced on www.astm.org.Available from Association for the Advancement of Medical Instrumentation, 1110North Glebe Road,
30、 Suite 220, Arlington, VA 22201-4795, U.S.A.4 Available from ISO Central Secretariat, Postal 56, 1211 Geneva 20 Switzerland. International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, CP 56,CH-1211 Geneva 20, Switzerland, http:/www.iso.org.5 Document produced by Working Group 1
31、of the Joint Committee for Guides in Metrology (JCGM/WG 1). Available free of charge at the BIPM website(http:/www.bipm.org).6 Available fromAssociation for theAdvancement of Medical Instrumentation, 1110 North Glebe Road, Suite 220,Arlington, VA22201-4795, U.S.A.Document producedby Working Group 2
32、of the Joint Committee for Guides in Metrology (JCGM/WG 2). Available free of charge at the BIPM website (http:/www.bipm.org).7 Available from International Commission on Radiation Units and Measurements, 7910 Woodmont Ave., Suite 800 Bethesda, MD 20814, U.S.A.ISO/ASTM 51707:2015(E)2 ISO/ASTM Intern
33、ational 2015 All rights reservedD 5 dH/dm (1)x 5 1n (ixi,i 51,2,3n (1)where:xi = individual values of parameters with i = 1, 2, 3 . n.3.2.2.1 DiscussionThe term mean is used generally when referring to a population parameter and the term average when referring to the resultof a calculation on the da
34、ta obtained in a sample.3.1.2 accuracy of measurementcloseness of the agreement between the result of a measurement and the true value of themeasurand.3.2.3 calibration curvecurve VIM, 4.31graphical representation of the dosimetry systems response function.expressionof the relation between indicatio
35、n and corresponding measured quantity value.3.2.3.1 DiscussionIn radiation processing standards, the term “dosimeter response” is generally used for “indication”.3.2.4 coeffcient of variationvariation (CV)sample standard deviation expressed as a percentage of sample meanaveragevalue (see 3.1.383.2.2
36、 and 3.2.193.1.39).):CV5Sn21/xH 3100% (2)CV 5Sx 3100 % (2)3.2.5 combined standard uncertaintymeasurement uncertainty VIM, 2.31standard uncertainty of the result of ameasurement when that result is obtained from the values of a number of other quantities, equal to the positive square root of asum of
37、terms, the terms being the variances or covariances of these other quantities weighted according to how the measurementresult varies with changes in these quantities.measurement uncertainty that is obtained using the individual standard measurementuncertainties associated with the input quantities i
38、n a measurement model.3.2.5.1 Discussion(1) It is also referred to as combined standard uncertainty.(2) In case of correlations of input quantities in a measurement model, covariances must also be taken into account whencalculating the combined standard measurement uncertainty.3.1.6 confidence inter
39、valinterval estimate that contains the mean value of a parameter with a given probability.3.1.7 confidence levelprobability that a confidence interval estimate contains the value of a parameter.3.1.8 corrected resultresult of a measurement after correction for systematic error.3.1.9 correctionvalue
40、that, added algebraically to the uncorrected result of a measurement, compensates for systematic error.3.1.9.1 DiscussionThe correction is equal to the negative of the systematic error. Some systematic errors may be estimated and compensated for byapplying appropriate corrections. However, since the
41、 systematic error cannot be known perfectly, the compensation cannot becomplete.3.1.10 correction factornumerical factor by which the uncorrected result of a measurement is multiplied to compensate fora systematic error.3.1.10.1 DiscussionSince the systematic error cannot be known perfectly, the com
42、pensation cannot be complete.3.2.6 coverage factorfactor (k) VIM, 2.38numerical factor used as a multiplier of the combined standard uncertainty inordernumber larger than one by which a combined standard measurement uncertainty is multiplied to obtain an expandedmeasurement uncertainty.ISO/ASTM 5170
43、7:2015(E)3 ISO/ASTM International 2015 All rights reserved3.2.6.1 DiscussionA coverage factor, k, is typically in the range of 2 to 3 (see 8.35.2.4).3.1.12 dosimeter batchquantity of dosimeters made from a specific mass of material with uniform composition, fabricated ina single production run under
44、 controlled, consistent conditions and having a unique identification code.3.1.13 dosimetry systemsystem used for determining absorbed dose, consisting of dosimeters, measurement instruments andtheir associated reference standards, and procedures for the systems use.3.1.14 error (of measurement)resu
45、lt of a measurement minus a true value of the measurand.3.1.14.1 DiscussionThe quantity is sometimes called “absolute error of measurement” when it is necessary to distinguish it from relative error. If theresult of a measurement depends on the values of quantities other than the measurand, the erro
46、rs of the measured values of thesequantities contribute to the error of the result of the measurement.3.2.7 expanded uncertaintyuncertainty GUM, 2.3.5quantity defining the interval about the result of a measurement thatmay be expected to encompass a large fraction of the distribution of values that
47、could reasonably be attributed to the measurand.3.2.7.1 DiscussionExpanded uncertainty is also referred to as “overall uncertainty” (see obtained 2.3, Guide to the Expression of Uncertainty inMeasurement). To associate a specific level of confidence with the interval defined by the expanded uncertai
48、nty requires explicitor implicit assumptions regarding the probability distribution characterized by the measurement result and its combined standarduncertainty. The level of confidence that may be attributed to this interval can be known only to the extent to which suchassumptions may be justified.
49、by multiplying the combined standard uncertainty by a coverage factor, the value of which determinesthe magnitude of the fraction. Expanded uncertainty is also referred to as overall uncertainty.3.1.16 expected valuesum of possible values of a variable weighted by the probability of the value occurring. For a discreterandom variable it is found from the expression:E5(i PiVi (3)where:Vi = ith value of discrete random variable, andPi = probability of ith value.For a continuous random variable x it is
