Designation:D6274−18StandardGuideforConductingBoreholeGeophysicalLogging-Gamma1ThisstandardisissuedunderthefixeddesignationD6274;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisguidecoversthegeneralproceduresnecessarytoconductgamma,naturalgamma,totalcountgamma,orgammaray(hereafterreferredtoasgamma)loggingofboreholes,wells,accesstubes,caissons,orshafts(hereafterreferredtoasboreholes)ascommonlyappliedtogeologic,engineering,groundwater,andenvironmental(hereafterreferredtoasgeo-technical)investigations.Spectralgammaandloggingwheregammameasurementsaremadeinconjunctionwithanuclearsourceareexcluded(forexample,neutronactivationandgamma-gammadensitylogs).Gammaloggingformineralsorpetroleumapplicationsareexcluded.1.2Thisguidedefinesagammalogasarecordofgammaactivityoftheformationadjacenttoaboreholewithdepth(SeeFig.1andFig.2).1.2.1Gammalogsarecommonlyusedtodelineatelithology,correlatemeasurementsmadeondifferentloggingruns,anddefinestratigraphiccorrelationbetweenboreholes(SeeFig.3).1.3Thisguideisrestrictedtogammaloggingwithnuclearcountersconsistingofscintillationdetectors(crystalscoupledwithphotomultipliertubes),whicharethemostcommongammameasurementdevicesusedingeotechnicalapplica-tions.1.4Thisguideprovidesanoverviewofgammaloggingincludinggeneralprocedures,specificdocumentation,calibra-tionandstandardization,andlogqualityandinterpretation.1.5ThisguideistobeusedinconjunctionwithGuideD5753.1.6Gammalogsshouldbecollectedbyanoperatorthatistrainedingeophysicalloggingprocedures.Gammalogsshouldbeinterpretedbyaprofessionalexperiencedinloganalysis.1.7ThevaluesstatedineitherSIunitsorinch-poundunits[giveninbrackets]aretoberegardedseparatelyasstandard.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvalu...
