COO Detector Activities

1. COO Detector Activities Roger Smith 2010-01-27

2. Delta Doped CCD demo Current Themes COO Detector Activities Precision Projector Galaxy shape measurement for Weak Lensing 10ppm relative photometry(ExoPlanets) 0.5%SupernovaPhotometry Wide field Imaging Spectroscopy NIR Wavefront Sensing

3. Sponsors (indicated in black) COO Detector Activities JPL DRDF … LBNL (DOE) Precision Projector Weak Lensing Transit Photometry Beichman (JPL DRDF+, NASA ROSES-SAT?) LBNL (DOE), JDEM (NASA) SN Photometry J.Johnson (CIT) LBNL (DOE) NIRES, DBSP-Red NIR WFS Caltech IRIS-OIWFS (TMT) Keck1 TTF (NSF ATI?) [ SUMIRE ?? ]

4. Palomar - PTF COO Detector Activities Operational support (tapering off): • Routine vacuum maintenance every 6 months. • Cryotiger monitoring. Leak? • Window contamination.

5. Delta Doped CCD demo on P60 COO Detector Activities • Collaboration with JPL. • Dewar intended to become lab CCD test system after demo and be template for DBSP-R upgrade and maybe SPOTcam for J.Johnson. • ∂ doped CCD production taking longer than anticipated. • Dewar concept developed but not modeled. …… Project suspended (postponed?)

6. CCD in picture frame Idea 2. Example slide from conceptual design Alternate transition card location Corner bolt threaded into frame ALN Metal frame presses on FG only where there is underlying Al Nitride

7. IR Spectroscopy COO Detector Activities • Extended effort to improve reliability of IR imager/guider for TripleSpec (Rahmer,Bonati,Hickey,Hale) • Recently, support for NIRES commissioning by Gustavo.

8. Optical Spectroscopy COO Detector Activities • DBSP Red side upgrade in project definition phase: • Extend red QE. • Lower noise • Faster readout; modern controller. • Better spectrograph controls? • Dewar design concept flows from DD-CCD project. • Modular concept will also lead to lab capability, and serve as precursor for J.Johnson’s transit camera.

9. 250µm thick and ITO DBSP-R QE Scenario COO Detector Activities • LBNL CCD QE > 90% in most of DBSP-Red range • May use eng grade CCD from SWIFT

10. Low order NIR WFS for TMT (IRIS) COO Detector Activities • Three R-theta probes each feed a 1024x1024 area of H2RG. Only J+H band required but 2.5µm detector chosen for best read noise. • Probe with brightest star is configured as 2x2 Shack-Hartman to measure focus+astigmatism, in addition to tip+tilt.

11. Camera design COO Detector Activities Mounting flange Snout containing long cold baffle and cold JH filter Thermal links, tuned Large getter container on cold head Cryotiger Light tight detector housing, thermally isolated and controlled

12. Readout mode for TMT-IRIS-OIWFS COO Detector Activities • 1Kx1K FoV is only 2 arcsec; used for acquisition. • Window progressively reduced to 4x4 pixels. • Small window is nested within concurrently exposed larger window. Large window readout is concurrently exposed to recapture spot if lost. • Developed sparse reset mode for ~100% duty cycle, and film strip mode for high frame rate tests. H2RG Acquisition region ~ 1k × 1k 2048 14×14 recapture window 4×4 guide window 2 mas/pix 2 arcsec 2048

13. Noise vs speed measurements COO Detector Activities • Multiple sampling beats noise down to ~2.7e- at 100 Hz guide rate for 4x4 window. Window size

14. Keck1 AO – TTF sensor COO Detector Activities • Similar detector and readout scheme, but K band at 800-1000Hz instead of JH at 80-800 Hz. • 100 mas/pixel; reimages full 120” AO FoV via dichroic for JH band science or annular mirror for K band science. • Move ROI instead of probe. • NSF ATI proposal submitted: Peter Wizinowich =PI; Thomas Stalcup = optical designer

15. SNAP funded NIR detector work COO Detector Activities • Studied noise in 1-3 hour exposures for 2.5µm HgCdTe. Sample up the ramp with CR rejection. Spatial and temporal noise compared. • Investigating linearity and alleged “initial signal deficit” (in progress) • H2RG power dissipation tests. • Commissioning of Precision Projector.

16. Spatial Noise v/s Effective Exp Time (91% Duty Cycle)Masking off high dark current pixels • Masking process: • Create mean frame out of 60 images using 3-sigma avsigclip, for 100s and 1000s exp times. • Subtract the two resulting mean frames: "mean_100-100.fits" • Select the 1/3 and 2/3 points from cumulative histograms. • Create masks replacing the masked-off pixels with out-of-range values ("1" for good pixels). • Multiply the original Fowler-91% images sets by each mask. • Calculate noise statistics on delta images, using "out-of-range" pixel value rejection on top of the usual outlier rejection (for CR).

17. SNAP CCD testing (pending) COO Detector Activities • Tests of random flat fielding errors at the sub-percent level due to pixel area variations, using spot projection to validate previous inferences from fourier transforms of PRNU images. • Validation our shrinking pixel hypothesis to explain the pixel to pixel correlations in shot noise, which throw off conversion gain calculations, and have mystified the CCD community since being reported by Mark Downing at the SPIE in Orlando in 2006

18. WL simulations (funded by NASA/JDEM) COO Detector Activities • We have supplied detector models for Jason Rhodes to simulate the effect of detector behavior on systematic shape measurement errors: • Persistence, linearity, reciprocity failure, read noise, correct handling of gain and quantization. • JPL has supplied Inter-Pixel Capacitance model. • The intent is to determine the sensitivity of WL errors to various detector effects, and thus determine requirements for calibration accuracy. This is being done as a function of plate to provide preliminary input to mission design selection for JDEM, SNAP, and possibly Euclid and HALO. • This exercise is limited by our imperfect understanding of the detector behavior at the 0.1% level.

19. Precision Projector (DRDF + SNAP funded) COO Detector Activities • Emulation of 0.1% galaxy ellipticity measurement in lab to validate control of systematics for Weak Lensing experiments. • The goal is to settle (inform?) the raging debate about how coarse the plate scale can be for various space missions doing WL. • Offner Relay with λ/100, 18” primary is designed to re-image chrome on glass mask bearing 2000 to 5000 “objects” ~ 2.5pixel FWHM, at Strehl>99.6% over full area of H2RG or SNAP CCD, for f/8 or slower beams for λ > 500nm. • Masks have 1µm minimum feature size and 50nm placement accuracy. • Mask stage provides 6 axis motion in 50nm increments.

20. Spot diagrams, encircled energy COO Detector Activities

21. Progress to date COO Detector Activities Primary mirror assembled in sling mount Secondary mirror procured. Mount is in shop. Masks procured and sample measured with electron microscope; 6 axis mask stage and integrating sphere in hand. Bench thermal control system built and tested.

22. Exoplanet Transits COO Detector Activities For John Johnson, Palomar instrument is in planning. For Chas Beichman, testing in support of ASTrO proposal later this year ($200M explorer class mission): • First cut: • Funded ($17K CIT, $13K JPL) to demonstrate plausibility of <100ppm photometry of a bright star relative to an ensemble of similarly bright stars, using Teledyne H2RG. • Will image a single pinhole through a lenslet array to create several hundred artificial stars with a common light source. • Next steps: • ROSES-TDEM proposal rejected, so JPL internal funds being sought for tests with Precision Projector in which PSF is well controlled and small pointing changes can be simulated.