【英文标准名称】:StandardPracticeforTransferStandardsforReflectanceFactorforNear-InfraredInstrumentsUsingHemisphericalGeometry
【原文标准名称】:半球形几何结构的近红外线仪器反射系数传送标准的标准实施规程
【标准号】:ASTME1791-1996(2008)e1
【标准状态】:现行
【国别】:美国
【发布日期】:1996
【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】:E13.11
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:hemisphericalopticalmeasurementsystem;integratingsphere;materialsstandards;reflectanceandreflectivity;transferstandards;Geometricanalysis;Hemisphericalgeometry;Infrared(IR)analysis--metals/alloys;Integratingspherereflectometer;Near-
【摘要】:Mostcommercialreflectometersandspectrophotometerswithreflectancecapabilitymeasurerelativereflectance.Theinstrumentreadingistheratioofthemeasuredradiationreflectedfromthereferencespecimentothemeasuredradiationreflectedbythetestspecimen.Thatratioisdependentonspecificinstrumentparameters.Nationalstandardizinglaboratoriesandsomeresearchlaboratoriesmeasurereflectanceoninstrumentscalibratedfrombasicprinciples,therebyestablishingascaleofabsolutereflectanceasdescribedinCIEPublicationNo.44(5).Thesemeasurementsaresufficientlydifficultandofprohibitivecostthattheyareusuallylefttolaboratoriesthatspecializeinthem.Astandardthathasbeenmeasuredonanabsolutescalecouldbeusedtotransferthatscaletoareflectometer.Whilesuchproceduresexist,theconstraintsplacedonthemechanicalpropertiesrestrictthesuitabilityofsomeoftheopticalproperties,especiallythosepropertiesrelatedtothegeometricdistributionofreflectedradiation.Thus,reflectancefactorstandardsthataresufficientlyruggedorcleanabletouseaspermanenttransferstandards,withtheexceptionofthesinteredPTFEstandards,departconsiderablyfromtheperfectdiffuserinthegeometricdistributionofreflectedradiation.Thegeometricdistributionofreflectedradiancefromsuchstandardsissufficientlydiffusethatsuchastandardcanprovideadependablecalibrationofadirectional-hemisphericalorcertaindirectional-directionalreflectometers.Althoughpressedpowderstandardsaresubjecttocontaminationandbreakage,thereflectancefactorofpressedpowdercanbesufficientlyreproduciblefromspecimentospecimenfromagivenlotofpowdertoallowtheassignmentofabsolutereflectancefactorvaluestoallofthepowderinalot.SinteredPTFEmaterialsexhibitsufficientreproducibilityfromwithinthesamespecimenafterresurfacingorcleaningthespecimentoallowtheassignmentofabsolutereflectancefactorvalues.PreparationofpackedpowderreflectancestandardsiscoveredinPracticeE259.ThispracticedescribesthespectralandphysicalpropertiesofthesematerialsandofthesinteredPTFEmaterials.1.1ThispracticecoversproceduresforthepreparationanduseofacceptabletransferstandardsforNIRspectrophotometers.ProceduresforcalibratingthereflectancefactorofmaterialsonanabsolutebasisarecontainedinCIEPublicationNo.44(9).BoththepressedpowdersamplesandthesinteredPTFEmaterialsareusedastransferstandardsforsuchcalibrationsbecausetheyhaveverystablereflectancefactorsthatarenearlyconstantwithwavelengthandbecausethedistributionoffluxresemblescloselythatfromtheperfectreflectingdiffuser.1.2ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:N53
【国际标准分类号】:37_020
【页数】:4P.;A4
【正文语种】:英语