1、Designation:D778412Standard Practice for theRapid Assessment of Gamma-ray Emitting Radionuclides inEnvironmental Media by Gamma Spectrometry1This standard is issued under the fixed designation D7784;the number immediately following the designation indicates the year oforiginal adoption or,in the cas
2、e of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers the quantification of radionuclidesin environmental media(e.g.,water,soil,ve
3、getation,food)bymeans of simple preparation and counting with a high-resolution gamma ray detector.Because the practice is de-signed for rapid analysis,extensive efforts to ensure homoge-neity or ideal sample counting conditions are not taken.1.2 The values stated in SI units are to be regarded asst
4、andard.The values given in parentheses are provided forinformation purposes only.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and deter
5、mine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C998 Practice for Sampling Surface Soil for RadionuclidesD1129 Terminology Relating to WaterD3370 Practices for Sampling Water from Closed ConduitsD3648 Practices for the Measurement of Radioacti
6、vityD3649 Practice for High-Resolution Gamma-Ray Spectrom-etry of WaterD7282 Practice for Set-up,Calibration,and Quality Controlof Instruments Used for Radioactivity Measurements2.2 Other Documents:PCNUDAT data files National Nuclear Data Center,Brookhaven National Lab,Upton,NY,USA3.Terminology3.1 D
7、efinitionsfor definitions of terms used in thispractice,refer to Terminology D1129.4.Summary of Practice4.1 Following sample collection,sample material is placedin a suitable container for analysis by a gamma spectrometrysystem.A suitable container is defined as a container whichwill both hold the s
8、ample in a fixed geometry and for which thegamma spectrometry system has been calibrated.For solidsamples,the samples may be ground,sieved,or otherwiseprepared for the purpose of volume reduction,homogenization,or conformance to the calibration standard,as desired.5.Significance and Use5.1 This prac
9、tice was developed for the rapid determinationof gamma-emitting radionuclides in environmental media.Theresults of the test may be used to determine if the activity ofthese radionuclides in the sample exceeds the action level forthe relevant incident or emergency response.The detectionlimitswillbede
10、pendentonsamplesize,countingconfiguration,and the detector system in use.5.2 In most cases,a sample container which is large indiameter and short in height relative to the detector willprovide the best gamma-ray detection efficiency.For samplesof water or other low-Z materials(e.g.,vegetation),there
11、-entrant or Marinelli-style beaker may yield the best gamma-ray detection efficiency.5.3 The density of the sample material and physical param-eters of the sample container(e.g.,diameter,height,material)may have significant consequences for the accuracy of thesample analysis as compared to the calib
12、ration.For this reason,the ideal calibration material and container(often referred to asgeometry)will be exactly the same as the samples to beanalyzed.Differences in sample container or sample matrixmay introduce significant errors in detector response,espe-cially at low gamma-ray energies.Every eff
13、ort should be madeto account for these differences if the exact calibration geom-etry is not available.5.4 This method establishes an empirical gamma-ray spec-trometer calibration using standards traceable to a nationalstandardizing body in a specific geometry selected to ensurethat the container,de
14、nsity,and composition of the standardmatches that of the samples as closely as possible.However,insome cases it may be beneficial to modify such initial calibra-tions using mathematical modeling or extrapolations to an1This practice is under the jurisdiction of ASTM Committee D19 on Water andis the
15、direct responsibility of Subcommittee D19.04 on Methods of RadiochemicalAnalysis.Current edition approved Nov.1,2012.Published November 2012.DOI:10.1520/D7784122For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of AST
16、MStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 alternate geometry.Use of such a model may be acceptable,depending on the measurement quality objectives of theanalysis process,and provided that appropriate compensationto uncertainty estimates are included.The use of such calibra-tion models is best supported by the successful analysis of amet