Designation:F658–00aStandardPracticeforCalibrationofaLiquid-BorneParticleCounterUsinganOpticalSystemBasedUponLightExtinction1ThisstandardisissuedunderthefixeddesignationF658;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversproceduresforcalibratinganddeterminingperformanceofanopticalliquid-borneparticlecounter(LPC)whichusesanopticalsystembaseduponlightextinctionmeasurement.ThispracticeisdirectedtowardsdeterminationofaccuracyandresolutionoftheLPCforcharacterizingthesizeandnumberofparticles,whichhavebeenpassedintothesampleinletoftheLPC.Considerationofinletsamplingefficiencyisnotpartofthispractice.1.2Theprocedurescoveredinthispracticeincludethosetomeasuresamplevolumeandflowrate,zerocountlevel,particlesizingandcountingaccuracy,particlesizingresolu-tion,particlecountingefficiency,andparticleconcentrationlimit.1.3Theparticlesizeparameterreportedinthispracticeistheequivalentopticaldiameterbasedonprojectedareaofcalibrationparticleswithknownphysicalpropertiesdispersedinliquid.ThemanufacturernormallyspecifiestheminimumdiameterthatcanbereportedbyanLPC;thedynamicrangeoftheLPCbeinguseddeterminesthemaximumdiameterthatcanbereportedforasinglesample.Typicalminimumreporteddiametersareapproximately2µm,andatypicaldynamicrangespecificationwillbeapproximatelyfrom50to1.1.4ThecountingratecapabilityoftheLPCislimitedbytemporalcoincidenceofparticlesinthesensingvolumeoftheLPCandbythesaturationlevelormaximumcountingratecapabilityoftheelectronicsizingandcountingcircuitry.CoincidenceisdefinedasthesimultaneouspresenceofmorethanoneparticlewithintheLPCopticallydefinedsensingzoneatanytime.Thecoincidencelimitisastatisticalfunctionofparticleconcentrationinthesampleandthesensingzonevolumewhenparticlesizeisinsignificantincomparisontothesensingvolumedimensions2.Thislimit...
