COO Detector Activities Roger Smith

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

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

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

Delta Doped CCD demo on P60 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?) COO Detector Activities 5

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

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

Optical Spectroscopy 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 COO Detector Activities 8

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

Low order NIR WFS for TMT (IRIS) 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 COO Detector Activities 10

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

Readout mode for TMT-IRIS-OIWFS 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 COO Detector Activities 12 H2RG 2048 Acquisition region ~ 1k × 1k 4×4 guide window 2 mas/pix 2 arcsec 14×14 recapture window

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

Keck1 AO – TTF sensor Similar detector and readout scheme, but K band at Hz instead of JH at 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 COO Detector Activities 14

SNAP funded NIR detector work 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 COO Detector Activities 15

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_ 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).

SNAP CCD testing (pending) 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 COO Detector Activities 17

WL simulations (funded by NASA/JDEM) 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 COO Detector Activities 18

Precision Projector (DRDF + SNAP funded) 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 COO Detector Activities 19

Spot diagrams, encircled energy COO Detector Activities 20

Progress to date COO Detector Activities 21 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.

Exoplanet Transits 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 COO Detector Activities 22