science imagers as high-energy radia4on sensors · 2017-11-28 · science imagers as high-energy...

ScienceImagersasHigh-EnergyRadia4onSensors

AshleyCarltonMassachuse<sIns4tuteofTechnology

SpaceTelecommunica4ons,Astronomy,andRadia4onLaboratory

ThesisProposalDefenseMay23,2017

33-218

Outline•  Introduc)on

–  BackgroundandMo)va)on–  ThesisOverview

•  LiteratureReview–  ImagersasRadia)onSensors

•  Approach&Methodology–  GalileoSSIandEPD–  DataAnalysisofSSIObserva)ons–  Simula)onsusingGeant4–  Ini)alresultsandcomparisontotheEPD

•  NextSteps–  GalileoNIMS–  In-labtes)ng

•  ThesisContribu)ons•  Schedule

–  Research,academic,degree

23May2017 A.Carlton 2

JovianMagnetosphere


Imagesource:PearsonEduca1on,2011

Earth JupiterEquatorialradius

[km] 6.38x103 7.15x104

Magne)cmoment[G-cm3] 8.10x1025 1.59x1030

Dipole)lt[o] 11.5 11

Rota)onperiod[hr] 24.0 9.925

Aphelion/perihelion[AU] 1.01/0.98 5.45/4.95

ContoursoftheintegralelectronandprotonfluxesattheEarthandJupiter.ImagecourtesyofI.Jun.

Jovianenvironmentisdominatedbyelectrons. [1,2]

LimitedHigh-EnergyMeasurements


TrajectoriesofspacecraDthathavemadehigh-energypar1clemeasurementswithrespecttoJupiter.RJ=71,492km.Imagesource:M.deSoria-SantacruzPichetal.,2016.

SpacecraO Orbit Date

Pioneer10 flyby December1973

Pioneer11 flyby December1974

Voyager1 flyby March1979

Voyager2 flyby July1979

Galileo 35orbits Dec.1995–Sept.2003

RJ=71,492km

MissionstoJupiterCurrentandplannedmissionstoJupiterdonothaveinstrumentsdedicatedtomeasuring>1MeVelectrons.

•  Juno:–  InorbitatJupiter(JOI:July2016)–  Highlyellip)calorbitoverthepoles[4]


•  EuropaClipperconcept:–  InphaseBofdesign,launchdate

~2024–  Consistsofanorbiter(flyingby

Europaoneachof~40-45highlyellip)calorbits)andlander[5,6]

VideoshowingtheplannedJunoorbitwithrespecttoJupiterandtheGalileanmoons.Videocreatedusing

NASA’sEyes:hXps://eyes.nasa.gov/

Whydowecareabout>1MeVe-?•  ScienceMo)va)on:

–  Magnetosphericscience–  MeVelectronsaffectsurfacesofJovianmoons[7,8]

•  EngineeringMo)va)on:–  Missionopera)ons–  Anomalyinves)ga)onandmi)ga)on[9,10]

–  Improvementofmodelsforfuturemissiondesign


Effect EnvironmentSource

1.Radia)ondose/doserate

100keV–50MeVelectrons1MeV–100MeVprotons

2.SurfaceCharging/ESD

1keV–1MeVelectrons

3.SingleEventEffects 1–100MeVprotons>1MeV/Nuc.heavyions

4.InternalCharging/IESD

1– 10+MeVelectrons

LimitedHigh-EnergyMeasurements


Flybysonly

~Equatorialorbit

Flybysonly

Polarorbit,minimalcoverageofradia)ondoseenergies

Nohigh-energypar)clemeasurementsplanned

Summaryofenerge1celectronmeasurementsatJupiter.Thecoloredregionshighlight

environmentswithpar1cularradia1onrisks.Imagecredit:A.Carlton

ThesisResearchStatement


Developamethodtoextractquan4ta4veinforma4onaboutthehigh-energy(>1MeV)electronenvironmentatJupiterusingexis4ngtechnologieson-board.

ScienceimagersassensorsoftheMeVelectrons.

DevelopthetechniqueusingimagersontheGalileospacecrahandcompareresultstoGalileoEnerge)cPar)cleDetector.

ImagersasRadia4onSensors


Averageenergyneededfore-hpairgenera)oninSilicon:3.6eV

Q∝ΔE

•  Impactioniza)on

•  Energe)cchargedpar)cleslosekine)cenergypredominatelythroughinelas)ccollisionswiththeorbitalsiliconelectrons

•  Electronspromotedfromvalencetoconduc)onband

Conduc)onband

Valenceband¢h

�e-

Si

Si

Si

Si

Si .... ....

Si

Si

Si

Si

Si .... ....

....

Valenceelectron

Covalentbond

Egap1.12eV

[11,12]

LiteratureReview

•  Radia)on“hits”/noiseextractedfromimagers–  Radia)onhitremovalalgorithms

[12,13,14,15]–  Comparingradia)onhitrateto

simula)ons[16]–  Comparingradia)onhitrateto

pre-flighttes)ngandtodifferentloca)onsonorbit[17,18,19]


OriginalCCDimage.Right:Imagewithcrossesindica1nganoisepixel.Imagesource:GirónandCorrea,2010.

Radia1on-inducedsignalratesinSSIimagesasafunc1onofRJ.Imagesource:Klaasenetal.,1999.

•  Imagersasradia)ondetectors–  Diagnos)csofiner)alconfinement

fusionimplosions[20,21]–  Threshold-crossingrates[22,23]

ApproachandMethodology(1/2)•  TheGalileospacecrahorbitedJupiterfromDecember1995toSeptember

2003,comple)ng35orbits.


Imagesource:NASAhXps://solarsystem.nasa.gov/images/galleries/Galileo_Diagram_No_Labels.jpg

•  DevelopthetechniqueusingSSIandNIMSimagersonGalileoascasestudiesandtheEPDtovalidate.

Beltonetal.,1992

Solid-StateImager(SSI)

Near-InfraredMappingSpectrometer(NIMS)

Carlsonetal.,1992

[24,25,26]

ApproachandMethodology(2/2)ForGalileoSSIandNIMS,wewill:•  Determinetheenergy(orenergies)the

imagerissensi)veto•  Calculatethefluxatagivenenergy•  CompareresultstotheGalileoEPD


Imagesource:NASAhXps://solarsystem.nasa.gov/images/galleries/Galileo_Diagram_No_Labels.jpgBeltonetal.,1992

Solid-StateImager(SSI)

Near-InfraredMappingSpectrometer(NIMS)

Carlsonetal.,1992

Energe4cPar4cleDetector(EPD)

Williamsetal.,1992[24,25,26]

Approach


• Collectrawinstrumentframeswithradia)onnoise

• Processframestoremovetargetanddarkcurrent

• Usecalibratedinstrumentgaintodetermineenergydeposited

DataAnalysis:Radia4onNoiseinSSIImages

• ModelinstrumentinGeant4

• Performmono-energe)csimula)ons

Simula4ons:InstrumentResponsetoMeVe-

• Determineinstrumentresponsetomono-energe)cbeams

• Determinefluxatagivenenergy

ExtractEnvironmentInforma4on

ComparetoEPDforvalida4on.

Approach:DataAnalysis(1/2)


1.Collectrawinstrumentframes(pictures)withradia)onnoise.

ScreenshotoftheimageatlasfromthePlanetaryDataSystem(PDS),whichcanbeaccessedhere:hXps://pds-imaging.jpl.nasa.gov/

ExampleSSIObserva)on:•  Orbit33,18Jan2002•  Integra)onTime:195.83ms

(exposure)+8.667s(read-out)•  ImagetakenatRJ=17.1

GalileoSSIimageofEuropa,downloadedfromthePDS.

2.Processframestoremovetargetobjectanddarkcurrent,leavingonlyradia)onhits.

Moonremoved

Right:Contrastedimagewiththeintensityscalerepresen1ngthedigitalnumberofthepixel.

Approach:DataAnalysis(2/2)


3.Usecalibratedinstrumentgaintodetermineenergydepositedperpixelperframefromnoise.Makehistogramofdepositedenergy.

Gainstatesforconver1ngtodigitalnumbertoelectrons[19].

CommandedGain

GainStateRa4oFactors

Conversion[e-/DN] Notes

0=Gain1 1.00 1822Summa)on

modeonly,~400Kfullscale

1=Gain2 4.824 377.4 Lowgain,~100Kfullscale

2=Gain3 9.771 186.5 ~40Kfullscale

3=Gain4 47.135 38.66 Highgain,~10Kfull255DNscale

Histogramoftheenergydepositedbypixel,aDerthedarkcurrentandmoonhavebeenremoved.

1bin=1DN=377.4e-=1.36keV

Approach:Simula4ons(1/2)


1.Modelfullinstrument(includingshielding)inachargedpar)cletransportsimula)oncode,Geant4.

Redorange:tantalumBrown:printedwiringboard

Yellow:siliconDarkblue:aluminum

Cyan:1taniumGreen:invarPink:silica

Imagesource:A.Carlton

Approach:Simula4ons(2/2)


2.Performsimula)onsofSSIundermono-energe)cenvironments.

Resul1ngimagefromsimula1ng1billion100MeVelectronsontheSSI.Imagesarein800by800pixelswiththeintensityscalerepresen1ngenergydepositedinapixel.

Sourceenvironment Sphereradia)nginwards

Radiusofsourcesphere 150cm

Numberofsourcepar4cles 1E9electrons

Energiessimulated 1,3,5,10,30,50,100,and200MeV

Simula1onparametersused.Theinputisessen1allyafluence,sincethe1mecomponentisnegligiblysmallforthesehigh-energyelectrons.

Histogramofresultsfromsimula1onof10billion50MeVe-.

Mono-energe4cSims:EnergyDeposited




Shapesofthecurvesaresimilaràmaynotbepossibletoextractspectra



Integralenergychannel~>10MeV

Geant4Results•  Sourceenvironmentsimulated:–  Onebillionmono-energe)celectrons–  Sphereradia)nginwardwithacosinedistribu)onandradiusr=150cm


Ra4oofthenumberofpar4clesreachingthe

detectorandthenumberofpixelswithhits,G1

Numberofpar4clesthatreachthedetector

Numberofpixelswithenergydeposited

Geant4Results•  Sourceenvironmentsimulated:–  Onebillionmono-energe)celectrons–  Sphereradia)nginwardwithacosinedistribu)onandradiusr=150cm






WefindG1=0.53±0.014(95%conf.)par)cles/pixel

GeometricScalingFactors


R1 = f0G2

1.  Calculatethera)oofpixelswithhitstopar)clesthatdepositenergyonthedetector•  R0:pixelhits/totalpixels•  R1:par)cles/totalpixels

2.  Tofindthenumberofpar)clesperunitarea,dividebythepixelsize

•  Pixelsize:15μmx15μm

3.  Usingtheknownfluencefromthesimula)onf0,computethegeometricviewfactor,G2

DeterminingthefluxfrompixelswithhitsontheSSIobserva)onrequiresscalingfactorsthatcanbecalculatedwiththeGeant4simula)ons.

R1 = R0G1 G1=0.53par)cles/pixel

f0 =N

4π (4πr2 )Simula)onfluence:f0=1.258x103#/cm2-sr

[par)cles/cm2]

Example:SSIObserva4on5101r,Orbit22-  SSIimageofAmalthea,takenat9.4RJ-  295pixelswithhitsoutof4161pixels(7.09%)-  Integra)on)me:62.5ms,Readout)me:8.667s-  Pixelsize:15μmx15μm


1.  Calculatethepixelhitrate:

2.  Par)clerate(frompar)clesintheenvironmentfromallenergies):

3.  ApplythescalefactorG2for10MeVandcalculatetheflux:

Image5101r,fromNASAPDS.

ComparisontoGalileoEPD


Log-normalfinngandEPD

uncertain1escanbefoundinJunet

al.,2005.

NextSteps•  GalileoSSI–  Buildconfidencein~10MeVintegralchannelbyperformingmoreGeant4simula)ons

–  ProcessallremainingSSIimagesandextractenergydeposi)oncurvesand>10MeVflux

–  ComparecurvestoEPD

•  GalileoNIMSanalysistodemonstratetechniquecanbeappliedtootherimagers

•  Tes)ngwithelectronbeamforvalida)onofGeant4modelingphysics–  Testsolid-statedetectorresponsetoenerge)celectronbeamsunderdifferentamountsofshielding


ExpectedContribu4ons•  Inventatechniqueanddesignageneralizedproceduretoextract

high-energy(>1MeV)electronenvironmentinforma)onfromsolid-statedetectors.–  Demonstratehowtofindatleastoneintegralenergychannelfromthe

GalileoSolid-StateImaginginstrument.–  Demonstratehowtofindatleastoneintegralenergychannelfromthe

GalileoNear-InfraredMappingSpectrometer(NIMS).–  DemonstrateagreementwiththeGalileoEnerge)cPar)cleDetector

(EPD).–  AnalyzeresultscomparedtocurrentJovianradia)onmodels(GIRE-2,

suppliedbyJPL).

•  Testsolid-statedetectorinelectronbeamstovalidateGeant4modelingphysics.

•  Composerecommenda)onsandrequirementsfortes)ng,calibra)on,

andopera)onalproceduresforaninstrumentontheEuropaClippermissioninordertousethetechniquedevelopedinthisthesis.


ResearchSchedule

Summer2017 Fall2017 Spring2018 Summer2018 Fall2018

GalileoSSI:Completeaddi)onalmono-energe)csimula)onsoftheSSIinGeant4todefineconfidenceintervalonenergyandfluxscalingfactors.Tes4ng:Supporttestplanandpartprocurement;Modeltestset-up;PerformtestsinlabWri4ng:Submitpaperonmastersresearch

GalileoSSI:Completeextrac)onofradia)oninfoandprocessingofallSSIimages;ComparisontoEPDandGIRE-2.GalileoNIMS:Beginanalysisofdata;Determinehowtoextracttheenergyandhitrateinfofromtheimages.Tes4ng:Post-processresults

GalileoNIMS:ModelingofNIMSinGeant4;Performsimula)onsWri4ng:WriteandsubmitpaperonSSIworkConferencepresenta)on(TBD)

GalileoNIMS:NIMSscalingfactors;ComparisonofNIMSresultstoEPDandGIRE-2,andtoSSI.Assessmentofgeneralizability,recommenda)onsforEuropaClipperinstrumentWri4ng:Writethesis

Wri4ng:Writethesis,defend,andgraduateConferencepresenta)on(TBD)


AcademicRequirements


Req. CourseNumber CourseTitle Semester

TakenGrade/Status

Major 16.413 Intro.toAutonomy&Decision-Making Fall2013 A

Major 16.851 SatelliteEngineering Fall2014 A

Major 16.363 Communica)onSystems Spring2015 A

Major 16.89 SpaceSystemsEngineering Spring2015 A

Major 16.899 SystemsEngineeringofFLAREproject Fall2016 A

Major 22.16 NuclearTechnologyandSociety Spring2015 A

Minor 16.910 Intro.toNumericalSimula)on Fall2014 A

Minor 16.343 SensorsandInstrumenta)on Spring2017 Inprogress

Minor 8.613OR8.701

PlasmaPhysicsORNuclearandPar)clePhysics Fall2017 Planned

DegreeMilestones


DegreeRequirement DateComplete

QualifyingExams January2016MastersDegree May2016

ThesisProposalDefense May23,2017ThesisDefense Summer2018(TBR)

References(1/2)


[1]F.Bagenal,T.Dowling,andW.McKinnon,eds.Jupiter:ThePlanet,SatellitesandMagnetosphere.CambridgeUniversityPress,2004.[2]H.Garrevetal.“TheJovianChargingEnvironmentandItsEffects–AReview”.In:IEEETransac1onsonPlasmaScience40.2(Feb.2012),pp.144–154.[3]M.deSoria-SantacruzPich,etal.,“Anempiricalmodelofthehigh-energyelectronenvironmentatJupiter”.InJ.Geophys.Res.SpacePhysics,121.10(2016).Pp.9732-9743.[4]S.Boltonetal.,“TheJunoMission”,In:ProceedingsoftheInt’lAstron.Union.6.S269(2010).Pp.92-100.[5]B.Goldsteinetal.,“EuropaClipperUpdate”.Presenta)onattheEuropaClipperOPAG,unpublished.Jan.2014.[6]C.PhillipsandR.Pappalardo.“EuropaClipperMissionConcept:ExploringJupiter’sOceanMoon”.In:EOS,Trans.Am.Geophys.Union95.20(2014),pp.165-167).[7]C.ChybaandC.Phillips,“Surface-SubsurfaceExchangeandtheProspectsforLifeonEuropa,”In:Proc.ofLunarandPlanetarySci.Conf,Vol.32,2001.[8]C.Paranicasetal.,“Europa’sRadia)onEnvironmentandItsEffectsontheSurface,”In:Europa.SpaceScienceSeries.UniversityofArizonaPress,2009.Chap.21,pp.529–544.[9]D.Has)ngsandH.Garrev,SpacecraD-EnvironmentInterac1ons.CambridgeAtmosphericandSpaceScienceSeries.Cambridge,UK:CambridgeUniversityPress,1996.[10]GordonWrenn.“ConclusiveEvidenceforInternalDielectricChargingAnomaliesonGeosynchronousCommunica)onsSpacecrah”.In:JournalofSpacecraDandRockets32.3(May1995).pp.514–520.[11]J.Janesick.Scien1ficCharge-CoupledDevices.Vol.PM83.Bellingham,Washington:SPIEPress,Jan.2001.[12]A.Yamashitaetal.“Radia)ondamagetochargecoupleddevicesinthespaceenvironment”.In:IEEETrans.onNuclSci44.3(June1997),pp.847–853.[13]A.Smithetal.“Radia)oneventsinastronomicalCCDimages”.In:Proc.SPIE4669,SensorsandCameraSystemsforScien)fic,Industrial,andDigitalPhotographyApplica)onsIII,172(April26,2002),pp.172–183.[14]L.ArchambaultL,T.Briere,S.Beddar,“Transientnoisecharacteriza)onandfiltra)oninCCDcamerasexposedtostrayradia)onfromamedicallinearaccelerator”.MedicalPhysics.2008;35(10):4342-4351.

References(2/2)


[15]A.D.RestrepoGirónandH.LoaizaCorrea,“Anewalgorithmfordetec)ngandcorrec)ngbadpixelsininfraredimages.IngenieríaeInves1gación,30(2),(2010).pp.197-207.[16]R.CarlsonandK.Hand.“Radia)onNoiseEffectsatJupiter’sMoonEuropa:In-SituandLaboratoryMeasurementsandRadia)onTransportCalcula)ons”.In:IEEETransac1onsonNuclearScience62.5(Oct.2015),pp.2273–2282.[17]K.Klaasenetal.,“Opera)onsandcalibra)onofthesolid-stateimagingsystemduringtheGalileoextendedmissionatJupiter,”In:SPIEOpt.Eng.42(2)(Feb.2003).Pp.494-509.[18]K.Klaasenetal.,‘‘Calibra)onandperformanceoftheGalileosolid-stateimagingsysteminJupiterorbit,’’In:SPIEOpt.Eng.38(7),(1999),pp.1178-1199.[19]K.Klaasenetal.,‘‘Inflightperformancecharacteris)cs,calibra)on,andu)liza)onoftheGalileosolid-stateimagingcamera,’’In:SPIEOpt.Eng.,36(11),(1997),pp.3001-3027.[20]B.E.Burkeetal.“Useofcharge-coupleddeviceimagersforcharged-par)clespectroscopy”.In:ReviewofScien1ficInstruments68.1(1997),pp.599–602.[21]C.K.Lietal.“Charged-coupleddevicesforcharged-par)clespectroscopyonOMEGAandNOVA”.In:ReviewofScien1ficInstruments68.1(1997),pp.593–595.[22]C.E.Grantetal.“UsingACISontheChandraX-rayObservatoryasapar)cleradia)onmonitor”.In:SpaceTelescopesandInstrumenta1on2010:UltraviolettoGammaRay.EditedbyArnaud7732(2010),p.80.[23]C.E.Grantetal.“UsingACISontheChandraX-rayObservatoryasapar)cleradia)onmonitorII”.In:SpaceTelescopesandInstrumenta1on2012:UltraviolettoGammaRay,8443(Sept.2012).[24]M.Beltonetal.“TheGalileoSolid-StateImagingexperiment”.In:SpaceScienceReviews60.1(1992),pp.413–455.[25]R.Carlsonetal.“Near-InfraredMappingSpectrometerexperimentonGalileo”.In:SpaceScienceReviews60.1(1992),pp.457–502.[26]D.Williamsetal.“TheGalileoEnerge)cPar)clesDetector”.In:SpaceScienceReviews60.1(1992),pp.385–412.[27]S.Agos)nellietal.“Geant4—asimula)ontoolkit”.In:NuclearInstrumentsandMethodsinPhysicsResearchSec1onA:Accelerators,Spectrometers,DetectorsandAssociatedEquipment506.3(2003),pp.250–303.[28]I.Junetal.,“Sta)s)csofthevaria)onsofthehigh-energyelectronpopula)onbetween7and28jovianradiiasmeasuredbytheGalileospacecrah”,Icarus,178(2),15November2005,pp.386-394.

HardElectronSpectrumatJupiter•  ComparisonbetweenJovianandTerrestrialradia)onspectra


MissionstotheOuterSolarSystemSpacecraO Jupiter Cost Mass(wet)

Pioneer10 Jupiter:1973,flyby $350M(FY2001) 258kg

Pioneer11 Jupiter:1974,flyby;Saturn:1979,flyby 259kg

Voyager1 Jupiter:1979,flyby;Saturn:1980,flyby

$900M

2080kg

Voyager2 Jupiter:1979,flyby;Saturn:1981,flyby;Uranus:1986,flyby;Neptune:1989,flyby 2080kg

Galileo Jupiter:1995-2003,orbiter;1995,2003atmospheric $1.41B 2223kg

Ulysses Jupiter:1992,2004,gravityassist $318M(FY1989) 371kg

Cassini-Huygens

Jupiter:2000,gravityassist;Saturn:2004-present,orbiter;2005,Titanlander $3.27B 5712kg

NewHorizons Jupiter:2007,gravityassist;Pluto:2015,flyby $700M 478kg

Juno Jupiter:2016-present,orbiter $1.1B 3625kg


CurrentModelsandLimita4onsModelName Reference Descrip4onandComments

DivineandGarrev(D&G)

DivineandGarrev,1983

Firstcomprehensivemodeloftheradia)onandplasmaenvironmentaroundJupiterEmpirical,fromGeigertubetelescope(GTT)onPioneer10and11,andfromthecosmicraytelescopeonVoyager1and2.

DivineandGarrev(D&G),updated

Garrevetal.,2005 IncludeddatafromEarth-basedobserva)onsoftheJupitersynchrotronemissions

JovianSpecificEnvironment(JOSE)

ONERA,FranceSicard-Pietetal.,2011

BasedonSalammbôtheore)calcodeincombina)onwithdatafromtheEnerge)cPar)cleDetector(EPD)ontheGalileospacecrah

GalileoInterimRadia)onEnvironment(GIRE)andGIRE2

Garrevetal.,2002;Garrevetal.,2012;deSoria-Santacruzetal.,2016

Empiricalmodel,uses10-minaveragesfromtheEnerge)cPar)cleDetector(EPD)onGalileoV2addressesdiscon)nui)esattheboundarybetweenGIREandtheD&Gmodelsandextendsfrom~16RJtoupto~50RJ


Currentmodelsarelimitedbylackofdata,bothspa)allyandtemporally.

KeyEnvironmentalInterac4ons


Tablecredit:H.GarreX

High-EnergyPar4cleMeasurements•  Juno:high-energypar)cle

measurementinstruments–  JovianAuroralDistribu)on

Experiment(JADE):•  Electrons:100eV–100keV•  Ions(1-50amu):10eV–40keV

–  JupiterEnerge)c-par)cleDetectorInstrument(JEDI):•  Electrons:20keV–1MeV•  Protons:15keVto3MeV


Effect EnvironmentSource

1.Radia)ondose/doserate

100keV–50MeVelectrons1MeV–100MeVprotons

2.SurfaceCharging/ESD 1keV–1MeVelectrons

2.SingleEventEffects 1–100MeVprotons>1MeV/Nuc.heavyions

3.InternalCharging/IESD 1–10MeVelectrons

•  EuropaClipper:noinstrumentscurrentlydedicatedtoMeVpar)cledetec)on

•  Whydowecare?Whyisthisnot

enough?

Imagesource:NASA/JPL-Caltech

ExtractInforma4onfromExis4ngHardware•  Scienceimagersare

1.  Commontoexplora)onmissions,suchasthosetoJupiter

2.  AffectedbyMeVpar)cles•  ThreeinstrumentsonJuno

areCCDs•  EuropaClipper:UVS,MISE,

EIS,andMASPEXaresensi)vetoMeVelectrons


Imagesource:NASA/JPL-CaltechStellarReferenceUnits(SRUs)

Goal:Usescienceimagerstomeasurethehigh-energyradia)onenvironment. Trash?

Treasure!

Opportuni4es:Juno•  MissionOverview:Juno–  JOI:July2016,nominalsciencetostartDec.2016–  Sciencephase:37orbits,20months–  Polarmeasurementsàgreaterorbitdiversity–  Junoequippedwithdetectorsfor1MeVe-and3MeVp+


•  ThreeinstrumentsareCCDs–  JunoColorCamera(JunoCAM)–  AdvancedStellarCompass(ASC)–  StellarReferenceUnit(SRU)

Junoorbitplan,resul1ngin24°spacingover15orbits.Imagesource:NASA/JPL-Caltech

(Note:ImagemadepriortoJOI.)

JunoInstrumentsandSystems


Opportuni4es:Europa•  MissionOverview:–  PhaseBofdesign,Launchdate:~2022– OrbiterandlandertostudyEuropa– Highlyellip)calorbitdesign


Imagesource:NASA/JPL-CaltechhXp://www.jpl.nasa.gov/missions/europa-mission/

•  NodetectorswithdedicatedMeVcapabili)esatall…

•  UVS,MISE,EIS,andMASPEXaresensi)vetoMeVelectrons

•  Measuredelectronenergyrangedeterminedbyinstrumentshieldingandsensi)vity

•  Beamtestsandtransportsimula)onsshouldbeperformedtocalibratetheinstrumentresponsetoradia)on

ApproachandMethodology•  TheGalileospacecrahorbitedJupiterfromDecember1995toSeptember2003,comple)ng35orbits.


Imagesource:NASAhXps://solarsystem.nasa.gov/galleries/galileo-diagram-labeled

Simula4onFluence•  1E9electronssimulated•  Spherewithradiusr=150cm•  Angulardistribu)on:cosine-law(uniform2πfluxfromaplane)


f0 =N

4π (4πr2 )=

1×109

4π (4π (150)2 )=1.258×103

90cm

150cm

e-

•  Needtomul)plybyafactorof4fortherealenvironment:–  Par)clesradiateinwardsandoutwards–  Angulardistribu)onisisotropic(whatwouldbeseenfromauniform4πflux)

Units:par)cles/sr-cm2

A B C D E F

Energy [MeV]

#Unique Hits

# Pixels with Hits

Hits to Pixels

Primaries Secondaries Total (B+C) Particle to Pixel Hits (D/E)

1 0 0 0 0 0

3 0 3 11 3 0.27

5 0 16 26 16 0.62

10 48 99 225 147 0.65

30 296 1001 2489 1297 0.52

50 622 2661 6151 3283 0.53

100 1144 7989 18263 9133 0.50

200 1999 20496 44650 22495 0.50

Simula4onRun2






WefindG1=0.54±0.056(95%conf.)par)cles/pixel

GalileoEnerge4cPar4cleDetector


10-minuteEPDintegralcountrate(leD)andomnidirec1onalflux(right)fortheDC3(>11MeV)channelasafunc1onofdistancefromJupiter.Ontheright,thedataarefitwithalinear(inred)andalog-normaldistribu1on(inblue).Thelog-normalaverageareabeXerfittothedata.Imagesource:I.Junetal.,2005

GalileoEPDUncertain4es


Plotoftheuncertainty(standarddevia1on)ofthera1ooftheobservedfluxtothepredictedfluxasafunc1onofdistance(binnedby1RJ).Imagesource:I.Junetal.,2005.

DistancefromJupiter,RJ,avg

10^STD(11MeV)

7.5 1.2808.5 1.5379.5 1.61610.5 1.74011.5 1.87212.5 1.83913.5 2.27014.5 2.70015.5 2.85416.5 2.75817.5 3.35918.5 2.91519.5 3.06920.5 3.10721.5 2.66722.5 3.40523.5 2.47824.5 2.77425.5 2.99826.5 2.89127.5 2.906

For11MeVintegralflux:

GalileoSSIImagesforAnalysis


BackupPlans•  IfitisnotpossibletoextractanintegralenergychannelfromeithertheSSIorNIMSinstruments(e.g.,theinforma)onextracteddoesnotagreewiththeEPD),wewillaugmentthenullresultwithaddi)onalanalysesofnon-tradi)onalsourcesofradia)oninforma)on.– AnalysisofGalileostartrackerdata(notimages,buthits)

– AnalysisofhousekeepingtelemetryfromGalileo– AnalysisofGalileo'sUltra-StableOscillators(USOs).USOfrequencyshihscorrespondtoradia)ondose.


GalileoSSIOpera4onandModes


•  Fourimagingmodes:

•  Eachframehasa“prepare”and“readout”opera)on.•  Exampleof8-2/3smode:

ImagingModes 2-1/3s 8-2/3s 30-1/3s 60-2/3s

PrepareTime 2/3s 2s 3-2/3s 7-1/3s

ReadoutTime 1-2/3s 6-2/3s 26-2/3s 53-1/3s

FilterStepsAllowed 1 2 3 7

Prepare:2seconds

Readout:6-2/3seconds

Claryetal.,1979

science imagers as high-energy radia4on sensors · 2017-11-28 · science imagers as high-energy...

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