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ATHENA WFI US ContributionsUSSWGCo-Chairsmeeting

January5,2017

PSU,MIT,SAO,Stanford/SLAC

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WFI has unprecedented sensitivity to extended sources

1/5/2017 USSWGCo-ChairsPresentation 2

• ATHENAwillhave~30xChandra’sareaandthusmuchbetterpointsourceandsurface-brightnesssensitivity

• VerylargeFOV(40’x40’),CCD-likeenergyresolution

• Probabilityofserendipitousdetectionoftransientsourcesisnotnegligible

• Lowandwell-understoodbackgroundisrequiredtoexploitthiscapability

.

XIFUFOV

WFIFOV

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US Contributions: Enhance science in 3 areas

1/5/2017 USSWGCo-ChairsPresentation 3

1) Transientsourcesa) Analyzeobservingtargetforvariability,providefeedbacktoinstrumenton

whethertheselectingobservingmodeisappropriateb) Searchforserendipitoussourcesbrighterthancatalogfluxes

2) Clustersandotherextendedsources:a) Improvebackgrounddeterminationthroughon-boardanalysisofallevents.

i. On-boardeventrecognitionrejects>99.5%ofbackgroundevents,whicharenottelemeteredtotheground

ii. On-boardbackgrounddeterminationcanimproveknowledgeofbackgroundlevelandvariability

3) Providecriticalmechanicalandelectronicsupportrequiredforsuccessfulinstrumentdesign

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US Contributions: 3-pronged approach

1/5/2017 USSWGCo-ChairsPresentation 4

1) ScienceProductsModule(SPM)a) Space-qualifiedprocessorboardtoperformancillaryanalysisonon-board

sciencedatastream(PSU)[TBD:Go/NoGodecisionwillbemadein2019]b) SPMsoftware

i. TransientAnalysisModule(PSU)ii. BackgroundAnalysisModule(MIT+SAO)

2) Front-endelectronicsASICdesign(Stanford/SLAC)3) PrimaryWFIMechanicalStructure

a) InterfacesbeingmonitoredbyGSFC,design/fabricationTBD

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WFI Block Diagram

1/5/2017 USSWGCo-ChairsPresentation 5

Cold Camera Head

Front-End Electronics

Frame Processor

Central !Processing !

Module

Commands! / Data

Instrument Control and Power distr. Unit (ICPU)

SPM

ASICs

ADCsDetector Electronics

Power Supply !Unit

DEPFET Sensors

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1) Science Products Module Software

1/5/2017 USSWGCo-ChairsPresentation 6

TransientAnalysisModule• Monitorscentralsourcefor

variabilityandpileup

• Searchesfortransientobjectsbycomparingimagestocatalogs

• Willbeabletofindshockbreakoutevents(likeSN2008D),TidalDisruptionEvents,andnewLMXBsandHMXBsinMilkyWayandnearbygalaxies

• InfoontransientswillbesenttogroundviaHKtelemetryforrapidprocessing

SN2008DSoderberg etal.2008

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1) Science Products Module Software

1/5/2017 USSWGCo-ChairsPresentation 7

BackgroundAnalysisModule• Processesfulldatastreamfromdetectorsto

measureinstrumentbackgroundon-orbit

• Onboardanalysishasaccessto~10xmorerawbackgrounddatathanistelemeteredtoground

• Produceshigh-levelproductsincludingbackgroundspectraandspatialbackgroundmaps

• Dataproductstelemeteredwithnormalsciencetelemetry(nottime-critical)

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2) ASIC Design

1/5/2017 USSWGCo-ChairsPresentation 8

• WFIrequiresextremelyhighspeedreadoutatextremelylownoisetoenableblackholesciencegoals• PerformanceofWFIdependscriticallyontheASICsthatreaditout• Noiselevelsmustbe<fewelectronsRMS

• MPEhasrequestedsupportfromSLACtodebugandrefinetheASICdesign