ASTM D4962-2002(2009) 用NaI(TI)γ射线光谱法处理水的标准实施规程

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【英文标准名称】:StandardPracticeforNaI(Tl)Gamma-RaySpectrometryofWater
【原文标准名称】:用NaI(TI)γ射线光谱法处理水的标准实施规程
【标准号】:ASTMD4962-2002(2009)
【标准状态】:现行
【国别】:美国
【发布日期】:2002
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D19.04
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:gammapulseheightanalysis;gammarayspectrometry;multichannelanalyzer;sodiumiodidedetector;Calibration--wateranalysisinstrumentation;Gammaradiation--water;Gamma-rayspectrometry;Multichannelanalyzer;Radioactivewateranalysis;Radionuclid
【摘要】:Gamma-rayspectrometryisusedtoidentifyradionuclidesandtomakequantitativemeasurements.Useofacomputerandalibraryofstandardspectrawillberequiredforquantitativeanalysisofcomplexmixturesofnuclides.Variationofthephysicalgeometryofthesampleanditsrelationshipwiththedetectorwillproducebothqualitativeandquantitativevariationsinthegamma-rayspectrum.Toadequatelyaccountforthesegeometryeffects,calibrationsaredesignedtoduplicateallconditionsincludingsource-to-detectordistance,sampleshapeandsize,andsamplematrixencounteredwhensamplesaremeasured.Thismeansthatacompletesetoflibrarystandardsmayberequiredforeachgeometryandsampletodetectordistancecombinationthatwillbeused.Sincesomespectrometrysystemsarecalibratedatmanydiscretedistancesfromthedetector,awiderangeofactivitylevelscanbemeasuredonthesamedetector.Forhigh-levelsamples,extremelylowefficiencygeometriesmaybeused.Quantitativemeasurementscanbemadeaccuratelyandpreciselywhenhighactivitylevelsamplesareplacedatdistancesof1mormorefromthedetector.Electronicproblems,suchaserroneousdeadtimecorrection,lossofresolution,andrandomsumming,maybeavoidedbykeepingthegrosscountratebelow2000countspersecondandalsokeepingthedeadtimeoftheanalyzerbelow5%.Totalcountingtimeisgovernedbytheactivityofthesample,thedetectorsourcedistance,andtheacceptablePoissoncountinguncertainty.1.1Thispracticecoversthemeasurementofradionuclidesinwaterbymeansofgamma-rayspectrometry.Itisapplicabletonuclidesemittinggamma-rayswithenergiesgreaterthan50keV.Fortypicalcountingsystemsandsampletypes,activitylevelsofabout40Bq(1080pCi)areeasilymeasuredandsensitivitiesofabout0.4Bq(11pCi)arefoundformanynuclides(1-10).Countratesinexcessof2000countspersecondshouldbeavoidedbecauseofelectroniclimitations.Highcountratesamplescanbeaccommodatedbydilutionorbyincreasingthesampletodetectordistance.1.2Thispracticecanbeusedforeitherquantitativeorrelativedeterminations.Intracerwork,theresultsmaybeexpressedbycomparisonwithaninitialconcentrationofagivennuclidewhichistakenas100%.Forradioassay,theresultsmaybeexpressedintermsofknownnuclidicstandardsfortheradionuclidesknowntobepresent.Inadditiontothequantitativemeasurementofgamma-rayactivity,gamma-rayspectrometrycanbeusedfortheidentificationofspecificgamma-rayemittersinamixtureofradionuclides.Generalinformationonradioactivityandthemeasurementofradiationhasbeenpublished(11and12).Informationonspecificapplicationofgamma-rayspectrometryisalsoavailableintheliterature(13-16).1.3ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitsofmeasurementareincludedinthisstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:Z16
【国际标准分类号】:13_060_30
【页数】:8P.;A4
【正文语种】:英语