LargeAreaX-rayPropor.onalCounter(LAXPC)instrumentandini.alscienceresults
(frompayloadverifica.onphase)
J.S.Yadav
TataIns.tuteofFundamentalResearchMumbai,India
19-Jul-16 JSYadav,TIFR 1
19-Jul-16
ACercomple.ngallelectronic&detectortestsandfinalcalibra.on,allthreeflightunitsofLAXPCinstrumentinAITlabforintegra.onwithsatelliteon20thOctober,2014.
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LAXPCinstrument`scapabili.esaresimilarorbeSerthanthatofNASA`sRXTE/PCA.
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PayloadsInstruments:
⋟ LargeAreaX-RayProportionalCounter(LAXPC)-TIFR
⋟ Softx-rayTelescope(SXT)-TIFR
⋟ CadmiumZincTellurideImager(CZTI)–TIFR
⋟ UltraVioletImagingTelescope(UVIT)–IIA
⋟ ScanningSkyMonitor(SSM)–ISAC
SXT LAXPC
CZTISSM
UVIT
ASTROSAT: Co-aligned multi-wave instruments
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Abroadenergyband(3-80keV)withhighdetec.onefficiencyofX-rayabove20keVandhigh.mingresolu.on10μsec..• Threeco-alignediden.calLAXPCdetectors
• Eachwithamul.-wire-mul.-layerconfigura.onfilledwith90%Xe+10%
Methanegasat1520torr.Energyresolu.on(12%@22keV)
• A50micronthickaluminizedMylarwindowforX-rayentrance
Mylarfilmsupport--byahoneycombwindowsupportcollimator
• Anarrowfieldofviewof.8x.8degsprovidedbymechanicalcollimatorsmade
ofasandwichof50µSn+25µCu+100µAlco-alignedwiththewindow
supportcollimatorandsiingaboveit.
• BlockingshieldonsidesandboSom:1mmSn+0.2mmCu
LAXPC: Large Area X-ray Proportional Counters (~419 Kg) (became fully operational on 19th Oct. 2015)
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LAXPCFlightPackages
LAXPC DETECTOR 1 AS-LX-DT-10
LAXPC
DETECTOR 2 AS-LX-DT-20
LAXPC
DETECTOR 3 AS-LX-DT-30
PROCESSING ELECTRONICS 1
AS-LX-EL-10
PROCESSING
ELECTRONICS 2 AS-LX-EL-20
PROCESSING
ELECTRONICS 3 AS-LX-EL-30
S. T. B. G.
AS-LX-EL-40
PURIFIER
ELECTRONICS (XPDE)
AS-LX-EL-50
Ø LAXPCpayloadhas8flightpackages.Ø ThreeDetectors,Ø CorrespondingProcessingElectronics,Ø CommonSTBGpackage,&XPDEpackage
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Detector System Brief description • LAXPC Instrument consists of 3 identical detectors. • Each LAXPC has the following major components : Field of View Collimator (FOVC) Window Support Collimator (WSC) Collimator Housing Anode Frames Detector Housing Back Plate
Detector hardware
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Detector hardware
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Harnesswiringofdetector
Detector Front-End Electronics
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LAXPC Detector on vibration table
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Sor.ngoutpurifica.oncartridgeissueinLAXPC30atISACon20thAugust,2014
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Calibration scan profile
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Lx10 spectra of sources at different temperatures (10°c,
20°c & 30°c)
LAXPC Calibration Meeting, Feb 2015 15
Labcalibra.on:GEANT4simula.onforLAXPC30unit&resultsforAmsource(all5layers)
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LAXPCinstrumentwillhavefour.mesormoreeffec.veareaabove20keVascomparedtoRXTE/PCA.Itcandetect0.1mcrabsourcesinfewthousandsecond.
ComparisonofLAXPCwithNASA’sRXTE/PCA
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Detectorperformance:On-boardPurifica.on&Detectorenergyresolu.on
l On-Board Purification for Flight Detectors
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EachoftheLAXPCdetectorshasanonboardgaspurifica.onsystem.Thissystemwillbeoperatedasandwhenrequiredtopurifythegasfilledinthedetectorbycommand.Itisexpectedthatenergyresolu.onofLAXPCdetectorwilldegradeasimpurityincreases.
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CAS–A(supernovaremnant)observa.onLAXPC30(leCtop)andRXTE/PCA(leCboSom).GX301-2observa.oninearlyMay2016showsimilarResolu.on(Ironlineisclearlyvisiblear6.4keV)
Energyresolu.onat6.4keVinorbit:Weachievedaround20%Energyresolu.onasproposed.
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RXTE/PCACAS-Aobserva.on
Crabobserva.onwithLAXPCandRXTE/PCA(NASA):RXTE/PCAtook3yearstofit2-60kevwithreducedCHIsquare~3whilewehavefitLAXPCspectrumin3-80kevwithreducedCHIsquare~1.4.LAXPCdetectorHashigherefficiencyathigherenergy(RXTE/PCAhas1c/s/keVat30keVwhileLAXPChasthisfluxvalueat60keV)
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RXTE/PCA
Atpresent,NASA,sNustarandLAXPCinstrumentareonlytwoX-rayspaceinstrumentswhichcover3-80keVenergyrange.HereweshowfittosimultaneousLAXPCandNustardataofCrab(aX-raypulsar)takenon1stApril,2016.Itisagoodfitwithreducedchisquare~1.04.Nustardatashowslargespreadathighenergywhichsuggeststhatitsdetec.onefficiencydecreasesfastat>30keV.
LAXPCinstrumentcapabili.es:comparisonwithNustar
RebinnedpowerdensityspectraofGRS1915+105(amicroquasar)inSPLstate.ItmatchesWellwiththepredictedPoissonnoiselevelwithdead.me42.3microsecondsandalowFrequencypowerlowcomponent.ThegreenlineshowstheexpectedpeakpowerofaQPOWithqualityfactorQ=4andrmsof5%.LAXPCinstrumentwoulddetectQPOofsuchaStrengtheasily.ll3000Hz.
LAXPCinstrumentcapabili.es:QPO(QuasiPeriodicOscilla.on)detec.on
Observa.on6thMarch2016
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LAXPCfirstresults: Crab(apulsar):
First light results: 4U 0115+63 (a pulsar in outburst)
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TransientX-raypulsar(3.6seconds)4U0115+63.HighMassX-rayBinarywithaneutronstar(highmagne.cfield)companionthataccretesmass
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RadiojetsobservedsimultaneouslywithGMRTRadioflaresduringX-raythetaclass:5-7March2016
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6.MicroquasarGRS1915+105insteeppowerlaw(SPL)state:Contribu.onofthermalandnon-thermalprocesstototalX-rayluminosity(leCpanel)andvaria.onofquasi-periodicOscilla.on(QPOs)withX-rayluminosity(rightpanel)
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DuringGRS1915+105observa.onduring5-7thMarch,2016SPL(steeppowerlaw)X-raystatewasobservedfor~10hrs.QPOfrequencychangesfrom2.5Hzto6Hz.
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LACPCini.alresults;CygX-1(persistentblackholeX-raybinary)
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CygX-1Energyspectrum
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LAXPCobserva.onofThermonuclearburstsandhighfrequencyQuasiPeriodicOscilla.on(HFQPOs):LAXPCobservedthermonuclearburstsintwoneutronstarX-raybinaries;4U1636-536and4U1728-34duringinstrumentverifica.onphase.Thesearethermonuclear(atombomb)explosionsonaccre.ngneutronstar.Rise.meis~1sec(X-rayfluxrisesbyafactorof~10)anddecay.me10-100sec.
4U1728-34
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ToppanelshowsdynamicpowerdensitySpectrumfromLAXPCobserva.onof4U1728-34.Weobservedburstoscilla.onforfirstFoursecat362.7Hz(toppanel).ItsuggeststhatthisthermonuclearburstshappensatEquatorandspreadsinfoursecandBecomeaxisymmetricbeltandQPODisappears(boSompanel)
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HighFrequencyQuasi-periodicOscilla.ons(HFQPOs):HFQPOsproberegionsclosetothecompactobjects(NeutronstarandblackholeSystems)whicharecharacterizedbyveryhighgravityandmagne.cfield.
ISCO12.5km
27km
15km
Orbitandfrequency
Observedfrequencyisalways<1.2KHz(for~2Msun).Theinnermoststablecircularorbit(ISCO)Isaround12.5kmwhichcorrespondsto1.2KHz(rightpanel).LeCpanelshowsdynamicPowerdensityspectrumfromLAXPCobserva.ons.Asmassfalls,qpoevolves(rises)andexploresextremecondi.onsnearneutronstar.QPOfrequencyevolvesfrom~820Hzto850Hz
LeCpanelshowsdynamicpowerdensitySpectrumfromLAXPCobserva.onof4U1728-34.Weobserved820HzHFQPOsshowingdriCtohigherfrequency.
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NGC4151withLAXPC103-80keVspectrumfit(5-50keVrangeexcluded)Whichclearlyshowspresenceofreflec.oncomponentandironline
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GRB160422AGRB160425A
LAXPCobservedGRBinApril,2016:lightcurvesandenergyspectrum:ThiswasnotinLAXPCobjec.ves,butwecanstudythem.Itwillneedsomeeffortstomodifydetectorresponse.
Conclusion
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Exciting Science to come … need more data of background
(once every month)
LAXPCInstrumentteam
Thanks!
JSYadavTIFRMumbai 3919/07/16
ISROSatelliteCentre(ISAC),Bangalore,RamanResearchIns.tute,Bangalore,
VikramSarabhaiSpaceCentre,Trivandrum,SpaceApplica.onsCentre,Ahmedabad
IUCAA,Pune&SeveralcolleaguesatTIFR,Mumbai,PRL,Ahemdabad