Designation:D4962−18StandardPracticeforNaI(Tl)Gamma-RaySpectrometryofWater1ThisstandardisissuedunderthefixeddesignationD4962;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversthemeasurementofradionuclidesinwaterbymeansofgamma-rayspectrometry.Itisapplicabletonuclidesemittinggamma-rayswithenergiesgreaterthan50keV.Fortypicalcountingsystemsandsampletypes,activitylevelsofabout40Bq(1080pCi)areeasilymeasuredandsensitivitiesofabout0.4Bq(11pCi)arefoundformanynuclides(1-10).2Countratesinexcessof2000countspersecondshouldbeavoidedbecauseofelectroniclimitations.Highcountratesamplescanbeaccommodatedbydilutionorbyincreasingthesampletodetectordistance.1.2Thispracticecanbeusedforeitherquantitativeorrelativedeterminations.Intracerwork,theresultsmaybeexpressedbycomparisonwithaninitialconcentrationofagivennuclidewhichistakenas100%.Forradioassay,theresultsmaybeexpressedintermsofknownnuclidicstandardsfortheradionuclidesknowntobepresent.Inadditiontothequantitativemeasurementofgamma-rayactivity,gamma-rayspectrometrycanbeusedfortheidentificationofspecificgamma-rayemittersinamixtureofradionuclidesbutthatabilityislimitedwhenusinglowenergyresolutionNa(Tl)detectorsascomparedtoHighPurityGermanium(HPGe)detectors.Generalinformationonradioactivityandthemea-surementofradiationhasbeenpublished(11and12).Infor-mationonspecificapplicationofgamma-rayspectrometryisalsoavailableintheliterature(13-16).1.3ThevaluesstatedinSIunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesafterSIunitsareincludedforinformationonlyandarenotconsideredstandard.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabilityofregu...
