1. Focal Plane Array Testing and Applications for Astronomy Donald Figer Space Telescope Science Institute

2. Outline The role of detectors in discovery. The state of the art in detectors. Keck/LGS/AO HST SOFIA Detectors and future Astronomy projects. LSST SNAP JWST

4. The Role of Detectors

5. Detector Functions Photometry Astrometry Spectoscopy Morphology Time Variability

6. Detector Types Eye Film Photomultiplier tube CCD Photodiode array Radio Antennae

7. Detector Wavelength Sensitivity X-rayVisibleNIRMIR [  m] Silicon 0.31.10.92.5520 HgCdTe InSb 0.1 InGaAs

8. CCD Architecture

9. Hybrid Architecture

10. light-sensitive layer substrate AR coating In bump

11. Keck

14. Keck/AO/LGS

15. HST: Hubble Space Telescope General-purpose orbiting astronomical telescope

16. HST

21. SOFIA: Stratospheric Observatory for Infrared Astronomy

22. LSST: Large Synoptic Survey Telescope What is the distribution of dark matter in the Universe? What is dark matter?

23. LSST

24. SNAP: Supernova Acceleration Probe What is dark energy?

25. SNAP Optical Configuration Telescope is a three-mirror anastigmat 2.0 meter aperture 1.37 square degree field Lightweight primary mirror Low-expansion materials Optics kept near 290K Transverse rear axis Side Gigacam location passive detector cooling combines Si & HgCdTe detectors Spectrometers share Gigacam focal plane Few moving parts in payload two-blade shutter for Gigacam focussers/adjusters at secondary & tertiary

26. SNAP Focal Plane Concept Coalesce all sensors at one focal plane. Imager sensors on the front. 36 HgCdTe 2kx2k 18  m 36 CCD 3.5kx3.5k 10.5  m Filters 1 of 3 per HgCdTe 4 of 6 per CCD Spectrograph on the back with access ports through the focal plane. Exposure times of 300 s with four/eight exposures in CCDs/HgCdTe.

27. JWST: James Webb Space Telescope What is the shape of the Universe? How do galaxies evolve? How do stars and planetary systems form and interact? How did the Universe build up it present elemental/chemical composition? What is dark matter?

28. JWST 6.5m diameter primary mirror launch in 2013 orbit at L2 four scientific instruments JWST deployment movie

29. IDTL: Independent Detector Testing Laboratory Located at Space Telescope Science Institute and Johns Hopkins University Founded 1999 Mission: Serve the astronomical community by developing and testing detectors for space and ground based astronomy programs

30. Eddie Bergeron Data Analyst Mike Telewicz Intern Gretchen Greene Mechanical Engineer Monica Rivera Intern Russ Pelton Technician Tom Reeves Lab Technician Bernie Rauscher Project Scientist Steve McCandliss JHU Lead Scott Fels Intern Sito Balleza Systems Engineer Robert Barkhouser Optical Engineer Utkarsh Sharma Graduate Student Ernie Morse Data Analyst Don Figer Director Mike Regan System Scientist Past and Present Personnel

31. IDTL Test System He Lines

32. IDTL Test System Figure 3.3. Mechanical drawing of cross section of IDTL dewar assembly. The optics with ray trace are also shown.Figer et al. 2002, SPIE, 4850, 981

33. IDTL Sample Results: Persistence (1200 seconds)

34. IDTL Sample Results: Read Noise

35. IDTL Sample Results: Dark Current

37. Dark Current Read NoiseGain Persistence Short-wave CutoffLong-wave Cutoff RQE vs. T IDTL Sample Results

38. IDTL Comparartive Detector Characterization

39. Properties of Silicon: Absorption Length

40. Properties of Silicon: QE

41. Properties of Silicon: Long Wave QE

42. Silicon 1  m QE vs. Thickness & Temperature

43. Properties of HgCdTe Nearly “ideal” characteristics. Many vendors.

44. Properties of InGaAs: QE

45. State of the Art: Thin CCD Nearly “ideal” characteristics. Many (~4) vendors.

46. State of the Art: LBNL Thick CCD QE

47. State of the Art: Si PIN Emerging technology. Chief Vendors - Raytheon Vision Systems (RVS) and Rockwell Scientifics Corp. (RSC). ParameterComments / Notes Read Noise< 10e- with multiple reads Dark Current~ 1fA/cm 2, @-100C Radiation Tolerance Robust On Chip logic Yes (on stacked ROIC) Readout Method many choices, ripple, snap shot, sub- frame imaging, pseudo random Support Electronics Generally requires multiple biases but support electronics are simple when compared to CCD drive electronics. Charge Capacity >100ke-, can be very large, cell size dependent.

48. State of the Art: Si PIN RQE (100  m thick)

49. State of the Art: Si PIN Hybrid Arrays Si PIN Hybrid QE Measures Data (from B. Pain, et. al.)

50. State of the Art: Si PIN Dark Current read noise in H2RG-003 (18  m pixels) 1e- on reference pixels, Fowler-32, 100 kHz 9e- on science pixels, Fowler-32, 100 kHz well depth, 120,000 e- QE@ 1  m 24%@140K 28%@160K 33%@180K 38%@200K Crosstalk, 2-3% Persistence, <0.3% 0.001 e-/s/pixel for 10  m pixel

51. State of the Art: Si PIN Read Noise 10 e 

52. State of the Art: HgCdTe Mature technology, although short-wave QE is recent development. Several vendors. Flight heritage NICMOS, 256x256, 2.5um cutoff. Hubble Wide Field Camera 3, H1RG, 2.3um cutoff. (Launch?) Deep Impact MRI spectrometer, H1RG, 5um cutoff. JWST NIRCam, NIRSpec, FGS, 2.5um and 5.0um cutoff. (Launch?)

53. State of the Art: HgCdTe Dark Current

54. State of the Art: HgCdTe Read Noise

55. State of the Art: InGaAs Emerging technology. Sensors Unlimited

56. State of the Art: SUI InGaAs QE DARPA contract to develop 1280 x 1024 InGaAs Array. Dark current goal of 2nA/cm2. Read noise ~ 10e - at video rates. Worth watching.

57. State of the Art: Photon Counting CCD Emerging technology. Two (more?) vendors. Low Light Level CCDs (L3CCDs), a.k.a. EMCCDs. Realized noise is 1.4 times value for non-photon counting mode. High read rate required in photon counting mode implies high power ~10 W per CCD for clocks and outputs.