The James Webb Space Telescope&its Infrared DetectorsBernard J. Rauscher1 & Mike Ressler2 for the JWST Team 1NASA Goddard Space Flight Center 2NASA Jet Propulsion Laboratory22 June 2005Scientific Detectors Workshop 2005 Taormina, Sicily*

JWSTs Detector Partners22 June 2005Scientific Detectors Workshop 2005 Taormina, Sicily*The following individuals contributed material on JWST detectors to this presentation James Garnett, Rockwell Scientific Alan Hoffman, Raytheon Vision Systems Markus Loose, Rockwell Scientific Craig McMurtry, U. Rochester

In addition, we have drawn on other JWST-related documents as needed. These are cited when it is practical to do so.

Presentation OverviewJWST ScienceJWST MissionInstruments, Detectors, and ASICsCosmic history from the Big Bang to today. JWST will elucidate the end of the dark ages and the beginnings of the galaxies that we see today.Spiral galaxy M81 seen in: (1) optical/Kitt Peak and , (2) 3.6 mm, (3) 8 mm, and 24 mm and (d) composite Spitzer images.JWSTs near and mid-IR wavelengths offer a very different perspective on the Universe compared to optical!

Top JWST Goal - Find the First Light after the Big BangHow and from what were galaxies assembled?What is the history of star birth, heavy element production, and the enrichment of the intergalactic material?How were giant black holes created and what is their role in the universe?Three instruments to do this: NIRCam (NASA/CSA), NIRSpec (ESA), MIRI (ESA/consortium/NASA), plus FGS-TF (CSA) as seen by COBEGalaxies,stars,planets,lifeGalaxyassembly??

JWST ScienceEnd of the dark ages: first light and reionizationThe assembly of galaxiesBirth of stars and protoplanetary systemsPlanetary systems and the origins of lifeGalaxies in the UDFThe Eagle Nebula as seen by HSTThe Eagle Nebula as seen in the near-infrared

Mission ObjectiveStudy the origin and evolution of galaxies, stars and planetary systemsOptimized for infrared observations (0.6 28 m)OrganizationMission Lead: Goddard Space Flight CenterInternational collaboration with ESA & CSA Prime Contractor: Northrop Grumman Space TechnologyInstruments: Near Infrared Camera (NIRCam) Univ. of ArizonaNear Infrared Spectrograph (NIRSpec) ESAMid-Infrared Instrument (MIRI) JPL/ESA & European ConsortiumFine Guidance Sensor (FGS) CSA DescriptionDeployable telescope w/ 6.5m diameter segmented adjustable primary mirrorCryogenic temperature telescope and instruments for infrared performanceLaunch in 2012 to Sun-Earth L2 5-year science mission (10-year goal)James Webb Space Telescope (JWST)todaywww.JWST.nasa.govConcept DevelopmentDesign, Fabrication, Assembly and Testmission formulationauthorizedconfirmation formission implementationlaunchscience operations...

JWST Inserted into L2 Orbit0

ISIM OverviewISIM is: The JWST Science Instruments Associated Infrastructure: Structure, C&DH, & FSWRegion 1Science Instrument Optics Assemblies Near Infrared Camera (NIRCam) Near Infrared Spectrograph (NIRSpec) Mid Infrared Instrument (MIRI), & Dewar1 Fine Guidance Sensor and Tunable Filter (FGS/TF)Optical Bench Structure Radiators and support structure (NGST-supplied)

Region 2 Focal Plane Electronics (FPE)Instrument Control Electronics (ICE, MCE)

Region 3ISIM Command & Data Handling (C&DH) Electronics

1The dewar was recently deleted. MIRI will use a cryocooler.

Instrument OverviewNear Infra-Red Camera (NIRCam)Detects first light galaxies and observes galaxy assembly sequence0.6 to 5 microns, 2 (4096x4096) 31mas pixels & 2 (2048x2048) 62mas pixelsSupports Wavefront Sensing & ControlUniv. of AZ - LMATC instrument; Marcia Rieke, PI

Near Infra-Red Spectrograph (NIRSpec)Measures redshift, metallicity, star formation rate in first light galaxies0.6 to 5 microns Simultaneous spectra of >100 objects2 (2048x2048) 100mas pixelsResolving powers of ~100, ~1000, ~3000ESA/Astrium provided, with NASA Detectors & MicroshutterFine Guidance Sensor (FGS) Ensures guide star availability with >95% probability at any point in the sky Includes Narrowband Imaging Tunable Filter Module CSA/EMS provided 2 (2048x2048) 68mas pixels John Hutchings, lead

Mid-Infra-Red Instrument (MIRI) Distinguishes first light objects; studies galaxy evolution; explores protostars & their environs Imaging 1 (1024x1024) 110mas pixels Spectroscopy (R~3000) 2 (1024x1024) 200-470mas pixels 5 to 27 microns; Cooled to 7K by cryocooler ESA/JPL, George Rieke, Gillian Wright leadsFormer location of dewar

Infrared Detectors for JWSTRockwell Scientific selected for NIRCam, NIRSpec and possibly FGSTotal of 19 Hawaii-2RG sensor chip assemblies (SCAs) for flight and flight spareRaytheon Vision Systems selected for MIRITotal of 6 SB-305 SCAs for flight and flight spare

Near-Infrared Detector Technology Development NICMOS and IRAC arrays demonstrated the basic detector architecture but with lower performance and smaller formats.TRL 4 achieved Feb 2002 with JWST performance levels achieved TRL 5 achieved Feb 2003 with JWST size 2Kx2K devices, mosaicing Astronomical Image with prototype, Sept. 2003

Image with JWST Prototype DetectorNGC 891 test image with Rockwell HgCdTe 4Kx4K array, Sept. 2003The first astronomical image to be obtained on JWST flight prototype near-infrared detectors. This three color image of the galaxy NGC891 was obtained using a 4096 x 4096 HgCdTe array produced by Rockwell Scientific Corporation under contract to JWST and the University of Hawaii KSPEC instrument on the UH 88 inch telescope.

Near-Infrared Detector Readout & ControlSCA Control by Rockwell SIDECAR ASICOne ASIC per SCADemonstrated performance met challenging JWST requirements in Feb., 2005JWST will fly a total of 16 near-infrared SCAs and 16 SIDECAR ASICs

Near-Infrared SCA Performance with SIDECAR ASICQuiescent lab conditionsRaw data & noise measurements as reported by RockwellIndependent analysis of the same data at NASA/GSFC confirms Rockwell findings for CDS and MULTIACCUM*. Did not look at Fowler samplingFlight representative2.5 mm cutoff SCASCA to ASIC electrical interfacesASIC*For the data that were provided, we found that we needed one additional calibration step compared to Rockwell. The additional step was similar to correcting for a small pedestal drift. It was needed because the reference pixels did not perfectly track the regular pixels.Baseline NIRSpec mode shown in Red. Uses 88 non-destructive samples up t~1000 s ramp.The above figure was presented by Rockwell Scientific as part of an ASIC review package. Test data and analysis are by Rockwell staff.Total Noise per 1000 s

Sheet1

Temporal combineSpatial Combine

Mode(e- rms)(e- rms)

Correlated Double Sampling (CDS)15.616.3

MULTIACCUM-22x45.24.95

Sheet2

Sheet3

SIDECAR ASIC Exceeds JWST Noise RequirementsSIDECAR ASIC has demonstrated excellent noise performance that exceeds the requirements for all three near-infrared instruments (37 K SWIR H2RG + ASIC)

1100 kHz pixel rate2 MULTIACCUM-22x4 calculated using 4 out of 6 measured ramps due to larger frame-to-frame pedestal in remaining 2 ramps.3Analysis of test data independently confirmed by NASA/GSFCTest results & analysis reported on this slide provided by Rockwell Scientific. Except where indicated, they have not yet been independently confirmed by NASA/GSFC.

Noise at low bias1Noise at medium bias1JWST RequirementASIC by itself (NIRSpec 4-22 multiaccum)2.0 e-1.8 e-2.4 e - (NIRSpec)ASIC + HAWAII-2RG CDS16.5 e-16.2 e-324 e- (extrapolated)ASIC + HAWAII-2RG Fowler 8-86.8 e-6.7 e-9 e- (NIRCAM)ASIC + HAWAII-2RG (4 22 multiaccum)5.3 e-5.2 e-2,36 e- (NIRSpec)

Near-Infrared Dark Current Tests Have Achieved the Required LevelsEngineering Unit JWST-009, substrate removed SWIR array, dark current histogram and mapTest results reported on this slide provided by Rockwell ScientificTest results & analysis reported on this slide provided by Rockwell Scientific. Except where indicated, they have not yet been independently confirmed by NASA/GSFC.

Visible QE Exceeds 80% at 800 nmEngineering Unit JWST-009, substrate removed SWIR array, QE histogram and map at 800nm - illumination non-uniformity not removedTest results reported on this slide provided by Rockwell ScientificTest results & analysis reported on this slide provided by Rockwell Scientific. Except where indicated, they have not yet been independently confirmed by NASA/GSFC.

Longer Wavlength QE Exceeds 80% As ExpectedEngineering Unit JWST-009, substrate removed SWIR array, QE histogram and map at 1230nm - illumination non-uniformity not removedTest results reported on this slide provided by Rockwell ScientificTest results & analysis reported on this slide provided by Rockwell Scientific. Except where indicated, they have not yet been independently confirmed by NASA/GSFC.

Mid-Infrared Technology DevelopmentConcept studies for a JWST mid-IR instrument begun in 1997Tentative detector requirements laid out in these studiesCraig McCreight led the Detector Working Group in 1999Looked at all technologies applicable to JWSTConcluded Si:As IBCs were most mature for mid-IRProduced Document 641 JWST detector roadmapContract with Raytheon in ~ 2000 to develop Si:As technology for JWST established by CraigJPL selected as U.S. MIRI lead in 2001MIRI detector competition announced in early 2003Raytheon competitively selected in May 2003PDRs begun in August 2003 that finalized designHybrid shown in a non-flight test mount

MIRI Focal Plane Primary RequirementsParameter

Format

Detector Material

Noise (Fowler-8 sampling)

Dark Current

QE:5 6 um6 12 um12 26 um26 28.2 umRequirement

1024 x 1024

Si:As IBC

< 19 e- @ 7.1 K

< 0.03 e-/sec @ 7.1 K

> 40%> 60%> 70%

> 5% (goal)Measured

1024 x 1024

Si:As IBC

10 e- @ 7.1 K

50%*> 60%*> 70%* (12 24 um)> 30%* (24 26 um)> 5%** QE estimated from AR coat reflectance measurements and QE measurements on non-AR coated detectorsSee Hoffman, A. et al. poster this conferenceTest results & analysis reported on this slide provided by Raytheon & their partners. Except where indicated, they have not yet been independently confirmed by NASA/JPL.

Raytheon Detector Assembly DesignPedestalCold Strap Interface Cable SCA Motherboard Attachment Feet 51 Pin Electrical Connector Cover/Baffle Thanks to RVS staff: Roger Holcombe, Rich Mullins, Barbara Ceriale, Margaret Olowski

Focal Plane Module DesignOBA Interface PlaneWith Locating Pin and SlotDetector Assembly20mm Thick Al 6061-T6Back Cover PlateBonded Fiberglass Thermal PortAl 6061-T6Cable Closeout PlateTitaniumThermal Strap SupportWith M6 BoltM5 Through HolesTemp Sensor ConnectorSCA Connector

Relative Spectral Response ComparisonsTest results & analysis reported on this slide provided by Raytheon & their partners. Except where indicated, they have not yet been independently confirmed by NASA/JPL.See Hoffman, A. et al. poster this conference

ROIC Read Noise at 7.1 K"Read noise versus Fowler Sampling at 7.1K for ROIC 1-25-C2. The integration time was 25 sec for all Fowler sampled images. Please note that one box was in a region that gave consistently higher noise which is due to excess row-banding in the first 80 rows. There is an occasional second point with higher noise due to cosmic ray hits (which were not filtered out). Therefore, we feel it is valid to ignore the 1-2 points outside the major groupings at each sampling."10 e- (Fowler-8)

2.5x lower noisethan SIRTF/IRACTest results & analysis reported on this slide provided by Raytheon & their partners. Except where indicated, they have not yet been independently confirmed by NASA/JPL.See Hoffman, A. et al. poster this conference