【英文标准名称】:StandardTestMethodforMeasuringNeutronFluenceRatebyRadioactivationofCobaltandSilver
【原文标准名称】:钴和银放射性活化法测定中子注量率的标准试验方法
【标准号】:ASTME481-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【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】:E10.05
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:activation;cobalt;dosimetry;foil;silver;thermalneutron;Cobalt-andsilver-foilmonitors;Fluence;Neutronactivationreactions;Neutronflux/fluence;Radioactivation--fastneutronflux;Silver-foilmonitors;Thermalneutronflux
【摘要】:ThepertinentdataforthesetworeactionsaregiveninTable1.Thistestmethodusesonemonitor(cobalt)withanearly1/vabsorptioncross-sectioncurveandasecondmonitor(silver)withalargeresonancepeaksothatitsresonanceintegralislargecomparedtothethermalcrosssection.TheequationsarebasedontheWestcottformalism(2,3)anddetermineaWestcott2200m/sneutronfluenceratenv0andtheWestcottepithermalindexparameterr1.1Thistestmethodcoversasuitablemeansofobtainingthethermalneutronfluencerate,orfluence,inwellmoderatednuclearreactorenvironmentswheretheuseofcadmium,asathermalneutronshieldasdescribedinMethodE262,isundesirablebecauseofpotentialspectrumperturbationsoroftemperaturesabovethemeltingpointofcadmium.1.2ThistestmethoddescribesameansofmeasuringaWestcottneutronfluencerate(Note1)byactivationofcobalt-andsilver-foilmonitors(SeeTerminologyE170).Thereaction59Co(n,x03B3;)60Coresultsinawell-definedgammaemitterhavingahalf-lifeof1925.28days(1).Thereaction109Ag(n,x02D9;x03B3;)110mAgresultsinanuclidewithacomplexdecayschemewhichiswellknownandhavingahalf-lifeof249.76days(1).Bothcobaltandsilverareavailableeitherinverypureformoralloyedwithothermetalssuchasaluminum.AreferencesourceofcobaltinaluminumalloytoserveasaneutronfluenceratemonitorwirestandardisavailablefromtheNationalInstituteofStandardsandTechnology(NIST)asStandardReferenceMaterial953.Thecompetingactivitiesfromneutronactivationofotherisotopesareeliminated,forthemostpart,bywaitingfortheshort-livedproductstodieoutbeforecounting.Withsuitabletechniques,thermalneutronfluencerateintherangefrom109cmx2212;2x00B7;sx2212;1to3x00D7;1015cmx2212;2x00B7;sx2212;1canbemeasured.Forthismethodtobeapplicable,thereactormustbewellmoderatedandbewellrepresentedbyaMaxwellianlow-energydistributionandan(1/E)epithermaldistribution.Theseconditionsareusuallymetinpositionssurroundedbyhydrogenousmoderatorwithoutnearbystronglyabsorbingmaterials.Otherwisethetruespectrummustbecalculatedtoobtaineffectiveactivationcrosssectionsoverallenergies.
【中国标准分类号】:F74
【国际标准分类号】:27_120_30
【页数】:7P.;A4
【正文语种】:英语