X Ray and Gamma Ray Measuring Instruments

1 Page 1 CalibrationofX-Rayand nist_^^ Gamma-RayMeasuring Publication Instruments 250-58 PaulJ.LampertI MichelleO'Brien Open at page → 2 Page 2 fhe NationalInstituteofStandardsandTechnologywasestablished in1988byCongressto"assistindustryin thedevelopmentoftechnology ...neededtoimproveproductquality,tomodernizemanufacturingprocesses,to ensureproductreliability .... Open at page → 3 Page 3 NISTSpecialPublication250-58 NISTMEASUREMENTSERVICES: CalibrationofX-RayandGamma-Ray IVIeasuringInstruments PaulJ.Lamperti MichelleO'Brien IonizingRadiationDivision PhysicsLaboratory NationalInstituteofStandardsandTechno... Open at page → 4 Page 4 Certaincommercial entities,equipment,ormaterialsmaybeidentifiedinthisdocument inorderto describeanexperimentalprocedureorconceptadequately.Suchidentification isnotintendedtoimply recommendation orendorsementbytheNational... Open at page → 5 Page 5 Foreword ThiseditionoftheNationalInstituteofStandardsandTechnology(NIST)SpecialPublication 250SeriesisarevisiontotheNBSSpecialPublication250-16CalibrationofX-Rayand Gamma-RayMeasuringInstrumentsdocument.Theoriginalworkha... Open at page → 6 Page 6 Abstract TableofContents Page ii Foreword iii Listoftables iv Listoffigures vii 1.0 Scope 1 2.0 Referencesdocuments 1 2.1 Internationalorganizationforstandardization 2.2 NationalInstituteforStandardsandTechnology 3.0 Ter... Open at page → 7 Page 7 8.3 Ionizationcurrentmeasurement-console equipment 42 8.3.1X-raycalibrationdataacquisitionsystem 42 8.3.2Gamma-raycalibrationdataacquisitionsystem 45 8.4 Pre-calibration testsofinstruments 46 8.4.1 Charger/reader lineari... Open at page → 8 Page 8 ListofTables Table4-1. Calibrationconditionsforx-rayandgamma-raymeasuring instruments Table4-2. Mammographyx-raybeam-qualityparameters Table4-3. ISOX-RayBeamQualityParameters Table6-1. DescriptionoftheNISTx-raysystems Ta... Open at page → 9 Page 9 Table6-13. CorrectionfactorsfortheAttixfree-airionization chamber 30 Table6-14. ResultsofthecomparisonoftheLampertistandardwiththe BIPMstandard 32 Table6-15. ResultsofthecomparisonoftheRitzstandardwiththeBIPM standard 32... Open at page → 10 Page 10 Table8-3. High-energyPantakunitvoltagecalibration 45 Table8-4. Temperatureprobeparametersforthegammasource calibrationranges 46 Table10-1. AnalysisofthreeNISTcheckchambersfortheperiod of1979to1997 53 Table11-1. Uncertain... Open at page → 11 Page 11 ListofFigures Fig.4-1 . Graphofgeneratingconstantpotentialagainsthalf-valuelayerfor thebeamqualitiesusedinthex-raycalibrationrange 7 Fig.4-2. Graphofhomogeneitycoefficientsagainstaluminumhalf-value layerfortheL,M,HandSfi... Open at page → 13 Page 13 1. Scope 1.1 Thisdocumentdescribesthex-rayandgamma-raycalibrationservicesprovidedbythe IonizingRadiationDivision,RadiationInteractionsandDosimetryGroupattheNational InstituteofStandardsandTechnology(NIST).Thecalibrationa... Open at page → 14 Page 14 3.1.2beamquality-usedtorefertoaspecificx-raybeamwithacharacteristichalf-valuelayer andproducedbyaconstantpotentialkilovoltage. 3.1.3 calibration -theprocesswherebytheresponseofadosimeterormeasuringinstrument is character... Open at page → 15 Page 15 4. Calibrationservice Thisreportdescribesthestatusofthecalibrationserviceforx-rayandgamma-ray measuringinstruments,asofJanuary1999.Thephysicalquantitiesair-kermaandexposure, calibrationbysubstitution,andthepropertiesofth... Open at page → 16 Page 16 stoppedinair.TheSIunitofexposureisthecoulombperkilogram(C/kg);thespecialunitof exposure,theroentgen(R),isequaltoexactly2.58E-4C/kg.Theionizationarisingfromthe absorptionofbremsstrahlungemittedbythesecondaryelectronsisnot... Open at page → 17 Page 17 Thequalitiesforeachgroupwerechosensothatrelativelysmoothcurvesresultforthegraphof tubepotentialversusHVL.Table4-1givesacompletelistingofbeamcodescurrentlyavailable atNIST.TheNBSbeamcodesusedpriortoJanuary1986arelistedinA... Open at page → 18 Page 18 Table4-1.Calibrationconditionsforx-rayandgamma-raymeasuringinstruments Beam code' AdditionalFilteration Half-valuelayerHomogeneity coefficient " Effective energy'' Distance Al Cu Sn Pb Al Cu Al Cu (keV) (cm; (mm)(mm)(mm)... Open at page → 19 Page 19 Fig.4-1Graphofgeneratingconstantpotentialagainsthalf-valuelayerforthebeamqualities usedinthex-raycalibrationrange.Thecurvesforhalf-valuelayersmeasuredincopperand aluminumareshownforthelight(L),moderate(M),heavy(H)andspec... Open at page → 20 Page 20 1 IMINI X s 0.01 0.10 1.00 10.00 100.00 Half-ValueLayer(mmAl) Fig.4-2.Graphofhomogeneitycoefficientsagainstaluminumhalf-valuelayerfortheL,M,H andSfiltrations.Thelinesconnectingthedatapointsareforeaseofveiwing. 8 Open at page → 21 Page 21 50 I \ ^ I I I I I 1 1 \ \ IMin i \ \ I I I I I I 0.01 0.10 1.00 10.00 Half-ValueLayer(mmCu) Fig.4-3.Graphofthehomogeneitycoefficientagainstthehalf-valuelayermeasuredincopper fortheM,HandSbeamqualities.Thelinesconnecting... Open at page → 22 Page 22 Table4-2.Mammographyx-raybeam-qualityparameters Beam Tube Additional Half-Value Homogeneity Code' Voltage Filtration'' Layer'' Coefficient (kVp) (mm) (mmAl) (Al) MoAnode Mo/Mo23 23 0.032Mo 0.271 70 Mo/Mo25 25 0.032Mo 0.2... Open at page → 23 Page 23 1.0 0.2 I ^ L_ \ \ \ 1 \ 1 \ 1 20 25 30 35 40 45 ConstantPotential(kV) Fig.4-4.GraphoftheHVL'softhemammographybeamquahtiesversusconstantpotential. 11 Open at page → 24 Page 24 Table4-3.ISOX-RayBeamQualityParameters Beam AddedFiltration(mm)" FirstHVL SecondHVL Code' Al Cu Sn PbmmAlmmCmmAlmmCu HKIO 0.04 0OS HK20 0 1s U.1J 0.13 016 HK30 0.39 0SQ HK60 'X1Q 0.08 011 U.11 HKIOO ^on 01s 0.31 046 HK20... Open at page → 25 Page 25 5.Designphilosophyandtheory X-raycalibrationsareperformedbyusingthesubstitutionmethod.Usingthismethod,theair kermaorair-kermarateisdeterminedatsomepointinspacebyafree-airchamber.The instrumenttobecalibrated isthenplaceda... Open at page → 26 Page 26 Table6-1.DescriptionoftheNISTx-raysystems. Features Unipolar^ Bipolar'' Mammography Manufacturer Pantak Pantak Gulmay Outputvoltage(kV) 5to100 5to320 5to50 Outputcurrent(mA) 0.5to80 0.5to30 0.1to40 Outputpower(kW) upto3.... Open at page → 27 Page 27 Telescope Leadand steel housing I Safetyshutter Beamaperture Test chamber Monitorchamber X-raybeam ~ cehTerrme Beamdefining filter X-raytube Timingshutter Movable supportcarriage Fig.6-1.Schematicof300kVx-rayrange. Colli... Open at page → 28 Page 28 HVplate Guardwires1cmspacings Diaphragm X-ray beam Guardplate Steelboxleadlined Collectorplate Fig.6-3.SchematicofWyckoff-Atix free-airionizationchamber. toelectrometerorground I I I Guard plate Diaphragm X-ray beam Coll... Open at page → 29 Page 29 SectionalSideElevation 1--- 11 - Fig.6-5.Schematiccross-sectionalviewsoftheLampertifree-airchamber. 1.Leadtomeasuringsystem,2.leadtothermistorreadout,3.thermistor,4.brasscollectorplate, 5.brassguardplate,6.brassguardring... Open at page → 30 Page 30 Beam defining aperture Signal Collectingelectrode Exit MoveablePlate Guard Sensitivecollectingvolume Entrance HVbias ushrod Steppingmotorslide2 Fig.6-6.SchematicofAttixfree-airchamber. tocompensateforthedownstreamlossofe... Open at page → 31 Page 31 6.3Calculationofairkerma Forafree-airionizationchamberwithvolumeV,theair-kermarateisdeterminedbytherelation K-^—T^^i (6-1) "air ciair where K^ theair-kermarate(Gy/s), I y = themassionizationcurrentmeasuredbythestandard(C... Open at page → 32 Page 32 6.4Wyckoff-Attix(50kVto300kV)free-airionizationchambercorrections Thecorrectionforelectronlossis K = \-ILA^jm (6-4) andthecorrectionforscatteredphotoncontribution is k^- \- (6-5) Inequation(6-4),E,.isthepercentelectronco... Open at page → 33 Page 33 Table6-4.Comparisonofx-raybeamfiltrationsusedfordatareportedinref[3]withtitrations presentlyusedforconventionalcalibrationconditions Reference[3] X-ray NBSSP-250 tube Inherent potential filter Pb (kV) (mm) (mm) AddedFilt... Open at page → 34 Page 34 Table6-5.DatausedtocomputecorrectionsfortheWyckoff-Attixstandardfree-airchamber forconventionalcalibrationconditions BeamCode 100(1- SAp lOO(l-kp) SApS. ^k^/k, M60 1.0203'' 0.77 0.9924 1.0140 MlOO 1.0097 0.60 0.9940 1.00... Open at page → 35 Page 35 Table6-6.Comparisonofthe valuescurrentlyusedtothosevaluescomputedfromtheleast squaresequation BeamCodeHVL(mmCu) Present LeastSquares M60 0.052 1.0203' 1.0128 MlOO 0.20 1.0097 1.0100 M150 0.67 1.0068 1.0076 M200 1.69 1.00... Open at page → 36 Page 36 Table6-7.Productsofallair-kerma-rate-independent correctionsfortheWyckoff-Attix free-air ionizationchamber BeamCode nk/k. Current nk/k^ Review DifferenceiVo) M60 1.0140 1.0074 0.65 MlOO 1.0052 1.0059 -0.07 M150 1.0058 1.... Open at page → 37 Page 37 thedefinedbeaminitsentiretyisinterceptedbythefree-airionizationchamberatthetwo measurementpositions.Theratioofthecurrentsmeasuredatposition 1andposition2istheair attenuationcorrectionfactorfortheconditionsofmeasurement.T... Open at page → 38 Page 38 occursonlyattheupperendofthex-rayenergyrangeforwhichthisfree-airionizationchamber isused.Therefore,onlyfigures10and14ofRef6arerequiredforcalculationofthe correctionsforbeamcodesS75andLI00.Thesedata,usedinconjunctionwitht... Open at page → 39 Page 39 1doieD-1u.SummaryofcorrectionsfortheRitzfree-airionizationchamber Beam AddedAl HVL Code filter (mmAl) 1a ka K nkj (mm) L20 U 0.071 0.9933 1.0000 0.9933" L30 0.265 0.22 0.9942 1.0000 0.9942" L40 0.50 0.49 1.0257 0.9949 1.... Open at page → 40 Page 40 fornormalroomtemperatureandpressure.Thisisaveryconservativestatementbecausethe assumptionsarethattheentireenergyofthehighestenergyphotonistransferredtoanelectron, andthattheCSDArangeisequaltothepracticalrange.Accordingto... Open at page → 41 Page 41 ThecorrectionspresentlyusedfortheLampertichamberaregiveninTable6-12where mostoftheairattenuationcorrectionsareshowntobedependentontemperatureandpressure andthecorrectionsforphotonscatterhavebeencomputedfromtheequationfor... Open at page → 42 Page 42 chamberforeachavailableaperture.Table6-13liststhephotonscattercorrectionsfora1cm aperture.TherecombinationcorrectionwasdeterminedusingtheproceduresuggestedbyScott andGreening[9].Therecombinationcorrectioniscalculatedfrom... Open at page → 43 Page 43 plateconfiguration. Forroutinemeasurements, thedefiningpointoftheAttixchamber,ispositionedatone meterfromthefocalspotofthex-raysource.However,forthedeterminationoftheHVL'sand theairattenuationcorrections,thedefiningpoint... Open at page → 44 Page 44 Table6-14.ResultsofthecomparisonoftheLampertistandardwiththeBIPMstandard Generatingpotential Half-valuelayer NIST/BIPM (kV) (mmAl) 1998 10 0.036 0.9950 30. ; 0.176 0.9961 25 0.250 0.9968 50(b) 1.021 0.9948 50(a) 2.257 0.... Open at page → 45 Page 45 Table6-17.ComparisonoftheRitzchambertotheNPL50kVstandard Generatingpotential (kV) Half-valuelayer (mmAl) NIST/BIPM 1998 20 0.15 0.9977 24 0.25 0.9978 34 0.35 0.9989 41 0.5 0.9973 44 0.7 0.9983 50 1.0 0.9983 Table6-18.Com... Open at page → 46 Page 46 Table6-20.Recent"in-house"comparisonsstandards Beamquality Half-valuelayer Ritz/Attix Lamperti/Attix Mo/Mo23 0.271 0.998 Mo/Mo25 0.296 0.997 0.998 Mo/Mo28 0.332 0.997 0.999 Mo/Mo30 0.351 0.999 0.997 Mo/Mo35 0.392 0.998 0... Open at page → 47 Page 47 7.0Gamma-rayairkermastandardsandcalibrationranges Therearesevengamma-raysourcesavailableforthecalibrationofinstrumentsforthe quantityofairkermaandfordeliveringknownexposurestopassivedosimeters.Thesourcesare collimatedand... Open at page → 48 Page 48 7.2Gamma-raysources Thelocation,nominalactivity,andorientationofthegamma-raysourcesusedfor instrumentcalibrationsaregiveninTable7-2.Figure7-1isaschematicofairradiatorhousing a''Cogamma-raysourcetypicalofthehorizontalgamm... Open at page → 49 Page 49 7.3Calibrationofgamma-raybeams Thehorizontalbeamcalibrationrangeswerecalibratedatvariousdistancesfromthe sources.Thedatawerefittoasuitablefunctionwhichallowsaccuratecomputationofairkerma ratesatselecteddistances,orofdist... Open at page → 50 Page 50 ''CosourcelocatedinB034,thereferencedistanceontheAl-channelmountedscaleis100cm. Theoffsetofthescale-zerofromthesourcecenteris47.9cm.Thehighestactivity^°Cosource availableforcalibrationworkislocatedinB036.Attheendof1989,t... Open at page → 51 Page 51 electrodesareweakenedandcarbonisdepositedonthehigh-voltageinsulator.The1cm\10 cm^and30cm^chambersareparticularlypronetothisproblemsincetheelectrodeshave diameterslessthan1mmand,withthepresentstemdesign,aredifficulttoanch... Open at page → 52 Page 52 Intheaboveequations,theK'sareconstantsandtheSDisthealuminumchannelscalereading incm.TheconstantsforeachsourcearelistedinTable7-5.Radiographsofthesebeams indicatea"hot"spotinthecentersoaconservativecomputationfortheuseful... Open at page → 53 Page 53 Table7-6.Beamsizedefinedby50%radiographicdensitycontourforvertical-beamgamma- raysources,forspecificcollimatorsettings Source Room Scale Collimator Beam Location Distance settings size (cm) (cm') (cm) ^"Cs B036 38 10.5X... Open at page → 54 Page 54 8.2.Electrometers TheKeithleyModel616electrometer'wasusedformanyyearsbytheNISTRadiation InteractionsandDosimetryGroupduetotheversatilityandtheabilitytouseexternalcalibrated capacitors.Keithleyoffersseveralothermodels,the... Open at page → 55 Page 55 (YSI).ThesensorsareconnectedtoYSImodel43TNreadouts.TheYSIreadoutisabridge circuitwhich,whenunbalanced,providesavoltageproportionaltothetemperature.Thereare fourYSItemperatureprobesusedinconjunctionwithmeasurementsonthe10... Open at page → 56 Page 56 shutter.Theleadthicknessinthetimingshutterwasminimizedformechanicalpurposesbutis ofsufficientthicknesstopreventsignificanteffectsoninstrumentreadingsintheinterval betweenoperationofthetwoshutters. Thechargemeasurementsar... Open at page → 57 Page 57 Table8-3.High-energyPantakunitvoltagecalibration NominalVoltage olopeY-Intercept 50 0.222 40.456 55 0.193 40.503 60 0.176 40.500 70 0.146 40.491 80 0.129 40.455 100 0.102 40.431 110 0.084 40.449 120 0.084 40.432 125 0.07... Open at page → 58 Page 58 Table8-4.Temperatureprobeparametersforthegammasourcecalibrationranges Temperatureprobe location slope intercept B021-B -0.201 42.830 B021-A -0.202 42.974 B015A -0.095 29.767 B015B -0.094 29.855 B036 1.006 -0.296 B034 1.0... Open at page → 59 Page 59 potentialfromthevoltagesourceisincreaseduntiltheimageofthestringcoincideswiththe zeromarkingonthescale.Thepotentialisrecordedfor"VO"ontheindexcardand,decreasing thepotential,dataarerecordedforthe(20,40,50,60,80and100)%of... Open at page → 60 Page 60 9.3.Pressureindicatorcalibrations Ananeroidbarometer,WallaceandTierman,ModelFA139,SerialNumberXXI1242, aswellasvariousotherlaboratoryreferencebarometersareperiodicallycalibratedbytheNIST ProcessMeasurmentsDivision.Calibr... Open at page → 61 Page 61 Aftertheinstrumenthasbeencahbratedthecalibrationreportisgenerated.Currentlythe reportsaregeneratedinWordPerfectorMicrosoftWord. Templatesareavailabletosimplifythis procedureandtoensureconsistencyinthereportingformat.Samp... Open at page → 62 Page 62 10.2.1.2.X-raycalibrations X-raycalibrationsareperformedusingthesubstitutionmethod:thestandardisusedto measuretheexposurerateatagivenpointinspace,thentheinstrumenttobecalibratedisplaced atthatpointandexposedtothesamecali... Open at page → 63 Page 63 10.2.1.3.Gamma-raycalibrations Theinstrumentstobecalibratedusinggamma-raybeamsarecalibratedinessentiallythe samewayasinthex-raybeams.Theprimarydifference isthatinthegamma-raybeams,aNIST standardisnotusedatthetimeofcalibr... Open at page → 64 Page 64 10.2.2.3.Gamma-raycalibrations Thistypeofcalibration isbasicallythesameasforx-rays,andessentiallynodifferent fromthegamma-raycalibrationofcondenserchambers. 10.3.Calibrationofcurrent-typeinstruments Backgroundinformation... Open at page → 65 Page 65 reproducibilityanddecidewhetherthecurrentvalueisacceptable. Forthegamma-rayandx-raycheckchambers,arecordismaintainedofallcalibrations, andthepreviouscalibrationsarecomparedwiththecurrentcalibrationtodetectanytrendor meas... Open at page → 66 Page 66 10.6.Irradiationofpassiveandelectronicdosimeters 10.6.1Generalconsiderationsandprocedures DosimetersreceivedatNISTforirradiationintermsofairkermaorexposurearethetypeused forpersonnelprotection.Theairkermafromx-rays,''^Cs... Open at page → 67 Page 67 11-1.Uncertaintyanalysisfortungstenxandgamma-rayair-kermarates,shownin% Gamma-raybeam X-raybeam Uncertaintycomponents TypeA TypeB TypeA TypeB airdensity 0.01 0.08 0.01 0.08 charge 0.03 0.1 0.12 0.06 humidity 0.07 0.07 vo... Open at page → 68 Page 68 Table 11-2Uncertaintyanalysisforgamma-raycalibrations,shownin% Current-type Condenser Passivedosimeters Uncertaintycomponents TypeA TypeB TypeA TypeB TypeA TypeB airkermarate 0.08 0.38 0.08 0.38 0.08 0.38 airdensity 0.01... Open at page → 69 Page 69 Table 11-4Uncertaintyanalysisformammography calibrations,shownin% Uncertaintycomponents TypeA TypeB airkermarate 0.31 0.29 charge 0.12 0.06 airdensity 0.10 0.08 humidity 0.05 distance 0.02 quadraticsum 0.33 0.31 combined... Open at page → 70 Page 70 tomaintainoptimalconditions.Table 11-6givesasummaryofexpandeduncertaintiesforeach typeofcalibration. Table11.6Summaryofexpandeduncertainties TungstenX-raysandGammaRaysMammographyX-rays airkermarate 0.8% airkermarate 0.9%... Open at page → 71 Page 71 range,alightbeamisusedforprotection.Inaddition,atime-delaydeviceinsidethe300kV x-rayrangemustbeactuateduponleavingortheshuttercannotbeopened.Asafurther indicationofradiationdanger,tworedlightsareturnedonwhenevertheshutte... Open at page → 72 Page 72 REFERENCES 1.Marshal,J.L.,ed.NISTCalibraitonServicesUsersGide,NIST(U.S.)Spec.Publ.250;1998 January.Availableon-line:http://www.ts.nist.gov/calibrations. 2.Boutillon,M.andPerroche-Roux,A.M.,Re-evaluationoftheWvalueforelec... Open at page → 73 Page 73 x-rays.Characteristicsandmeasurementprocedures,"ReportRT/PROT(83)27, LaboratoriodiMetrologiadellaRadiazionilonizzaniENEA,CRECasaccia,c.p.2400 Roma,Italia,1984. 16.Bums,D.T.,Lamperti,P.andO'Brien,M."ComparisonoftheNISTand... Open at page → 74 Page 74 AuroraRoad,Cleveland,OH44139(1977). 30.InstructionManual,Model642Electrometer,KeithleyInstruments,Inc.,28775Aurora Road,Cleveland,OH44139(1980). 31.Rutkowski,G.B.,HandbookofIntegrated-Circuit OperationalAmplifiers,Prenti... Open at page → 75 Page 75 Attachment 1 :X-RayBeamQualitiesofferedatNBSPriorto1986 Open at page → 76 Page 76 1dulcr\-1 . X-raybeamqualitiesofferedatNBSpriorto1986 LightlyFilteredX-Rays Beam Constant Distance Added Half-ValueLayer Homogeneity Code roiennai Filter^' Coeriicient V ; (mmAl) (mmAl) (Al) 10 75 0 0.03 nTO U./y 1J 0 0.... Open at page → 77 Page 77 Attachment2 :Additionalreferences -databooks Open at page → 78 Page 78 ThereferenceslistedinthisattachmentareNISTregisteredlaboratorydatabooks(DB)or binderswhicharelocatedinB033oftheRadiationPhysicsbuilding.Thereferencesare identifiedbythedatabookidentificationnumberandthepagenumber. 1.DB84... Open at page → 79 Page 79 Attachment3 :Attixchamberschematics Open at page → 80 Page 80 .21.27cm ChamberCenter 1mfromSource -^1.27cm Fig.A3-1.Attixchamberconfigurationforhalf-valuelayerandairattenuationmeasurements. 68 Open at page → 81 Page 81 ChamberCenter 21.27cmfromAperture Aperture 1mfromsource 15.5cm Fig.A3-2.Attixchamberconfigurationforthetwosmallestpositionsofroutinecalibrations. ChamberCenter 21.27cmfromAperture Aperture 1mfromsource 8cm 25cm " 10.5cm'... Open at page → 82 Page 82 Attachment4 :Thehistoryofthemeasurementofcurrent 70 Open at page → 83 Page 83 Untilhigh-gainnegative-feedback ampHfierswereintroduced,electrometersusedfor ionizationcurrentmeasurementswereusedasnulldetectors.Charge,orcurrent,wasmeasured bymanuallynullingthesignalonthemostsensitiverangeoftheelectro... Open at page → 84 Page 84 Fig.A3-1 .Circuitofanegative-feedback amplifierwithresistivefeedback. Open at page → 85 Page 85 Forlow-currentmeasurementshigh-megohm(MQ.)resistorsarerequired.Forexample, afeedbackresistorof20Mflisrequiredtodevelopafeedbackvoltageof1Vforthe exceptionallylargeionizationcurrentof50nA.DayandAttix[24]foundthatthehigh-m... Open at page → 86 Page 86 gainmaybeashighas50000. Fig.A3-2.Circuitofanegativefeedbackamplifierwithacapacitivefeedbackelement. Open at page → 87 Page 87 Attachment5 :Typicalionizationchambercalibrationreport Open at page → 88 Page 88 NationalInstituteofStandardsandTechnology REPORTOFAIR-KERMACALIBRATION OF ADDRESS 1 ADDRESS2 ADDRESS3 RadiationDetectionChamber:Make,Model,SN MeasurementsperformedbyMichelleO'Brien ReportreviewedbyPaulLamperti Reportappr... Open at page → 89 Page 89 NationalInstituteofStandardsandTechnology REPORTOFAIR-KERMACALIBRATION OF ADDRESS 1 ADDRESS2 ADDRESS3 RadiationDetectionChamber:Make,Model,SN Chamberorientation:thecavitywaspositionedinthecenterofthebeamwiththestemofthec... Open at page → 90 Page 90 ConventionalCalibrationConditions forX-andGamma-RayMeasuringInstruments OCell11 code AdditionalFiltration ^ Half-valuelayer Homogeneity coefficient i^llCL'llvc energy Al (mm) Cu (mm) Sn (mm) Pb (mm) Al (mm) Cu (mm) Al Cu... Open at page → 91 Page 91 ExplanationofTermsUsedintiieCalibrationProceduresandTables AirKerma :Theair-kermarateatthecalibrationpositionismeasuredbyafree-airionizationchamberfor Xradiationandbygraphitecavityionizationchambersfor^"Coand''^Csgammara... Open at page → 92 Page 92 Useofthechamberatotherpressuresandtemperaturesrequiresnormalizationoftheioncurrentstothese referenceconditionsusingthenormalizingfactorF(seebelow). EffectiveEnergy :Theeffectiveenergyisshownforthosebeamswhereitisconsider... Open at page → 93 Page 93 Attachment6:TypicalTLDcalibrationreport Open at page → 94 Page 94 NationalInstituteofStandardsandTechnology REPORTOF'''CsIRRADIATION OF ADDRESS 1 ADDRESS2 ADDRESS3 MeasurementsperformedbyRonnieMinniti ReportreviewedbyPaulLamperti ReportapprovedbyStephenM.Seltzer FortheDirector National... Open at page → 95 Page 95 NationalInstituteofStandardsandTechnology REPORTOFCsIRRADIATION OF ADDRESS 1 ADDRESS2 ADDRESS3 DosimeterType: BadgeOrientation: frontfacenormaltotheincidentradiation. AirKermaRate:X.XXEOGy/s. TLDIdentification Exposed To... Open at page → 96 Page 96 Attachment 7:Typicalelectrometercalibrationreport 84 Open at page → 97 Page 97 NationalInstituteofStandardsandTechnology REPORTOFTEST OF ADDRESS 1 ADDRESS2 ADDRESS3 Electrometer:Make,ModelSN MeasurementsperformedbyMichelleO'Brien ReportreviewedbyPaulLamperti ReportapprovedbyStephenM.Seltzer Nationa... Open at page → 98 Page 98 THESP250SERIESONNISTMEASUREMENTSERVICES* SP250-1 SpectralRadianceCalibrations PB87179883 SP250-2 FarUltravioletDetectorStandards PB87227609 SP250-3 RadiometricStandards intheVacuumUltraviolet PB87227625 SP250-4 FrickeDos... Open at page → 99 Page 99 THESP250SERIESONNISTMEASUREMENTSERVICES*-Continued SP250-45 RadiationProcessingDosimetryCalibration Services:ManualofCalibrationProcedures SN003-003-03514-9, PB98-140981 SP250-46NISTMultifunctionCalibrationSystem SN003-0... Open at page → 101 Page 101 TechnicalPublications Periodical JournalofResearchoftheNationalInstituteofStandardsandTechnology—ReportsNISTresearchand development inthosedisciplinesofthephysicalandengineeringsciences inwhichtheInstituteisactive. These... Open at page →