1、Designation:C1726/C1726M10Standard Guide forUse of Modeling for Passive Gamma Measurements1This standard is issued under the fixed designation C1726/C1726M;the number immediately following the designation indicates theyear of original adoption or,in the case of revision,the year of last revision.A n
2、umber in parentheses indicates the year of lastreapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide addresses the use of models with passivegamma-ray measurement systems.Mathematical models basedon physical principles can be used
3、 to assist in calibration ofgamma-ray measurement systems and in analysis of measure-ment data.Some nondestructive assay(NDA)measurementprograms involve the assay of a wide variety of item geom-etries and matrix combinations for which the development ofphysical standards are not practical.In these s
4、ituations,mod-eling may provide a cost-effective means of meeting usersdata quality objectives.1.2 A scientific knowledge of radiation sources anddetectors,calibration procedures,geometry and error analysisis needed for users of this standard.This guide assumes that theuser has,at a minimum,a basic
5、understanding of theseprinciples and good NDA practices(see Guide C1592),asdefined for an NDA professional in Guide C1490.The user ofthis standard must have at least a basic understanding of thesoftware used for modeling.Instructions or further training onthe use of such software is beyond the scope
6、 of this standard.1.3 The focus of this guide is the use of response models forhigh-purity germanium(HPGe)detector systems for the pas-sive gamma-ray assay of items.Many of the models describedin this guide may also be applied to the use of detectors withdifferent resolutions,such as sodium iodide o
7、r lanthanumhalide.In such cases,an NDA professional should determinethe applicability of sections of this guide to the specificapplication.1.4 Techniques discussed in this guide are applicable tomodeling a variety of radioactive material including contami-nated fields,walls,containers and process eq
8、uipment.1.5 This guide does not purport to discuss modeling for“infinite plane”in situ measurements.This discussion is bestcovered in ANSI N42.28.1.6 This guide does not purport to address the physicalconcerns of how to make or set up equipment for in situmeasurements but only how to select the mode
9、l for which thein situ measurement data is analyzed.1.7 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from th
10、e two systems may result in non-conformancewith the standard.1.8 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.2.Referenced Documents2.1
11、 ASTM Standards:2C1490 Guide for the Selection,Training and Qualification ofNondestructive Assay(NDA)PersonnelC1592 Guide for Nondestructive Assay MeasurementsC1673 Terminology of C26.10 Nondestructive Assay Meth-ods2.2 Other Standard:3ANSI N42.28 Performance Standard for the Calibration ofGermanium
12、 Detectors for In Situ Gamma-Ray Measure-ments3.Terminology3.1 See Terminology C1673.4.Summary of Guide4.1 Passive gamma-ray measurements are applied in con-junction with modeling to nondestructively quantify radioac-tivity.4.1.1 Modeling may be used to(1)design and plan themeasurements,(2)establish
13、 instrument calibration,(3)inter-pret the data acquired,(4)quantify contributions to themeasurement uncertainty,(5)simulate spectra,and(6)evaluatethe effectiveness of shielding.1This practice is under the jurisdiction of ASTM Committee C26 on NuclearFuel Cycle and is the direct responsibility of Sub
14、committee C26.10 on NonDestructive Assay.Current edition approved March 1,2010.Published April 2010.DOI:10.1520/C1726_C1726M-10.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,re
15、fer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.1.2 V
16、arious models commonly use analytical,numericalintegration and radiation transport approaches.This guideprovides a brief review of several approaches to help the userselect a suitable method and apply that method appropriately.4.1.3 Modeling makes use of knowledge of the measure-ment configuration including the shape,dimensions and mate-rials of the detector,collimator,and measurement item content.4.1.4 The exact geometry may be approximated in themodel.The degree of approximation acceptable is