Transcript SNAP, IRIS WFS, Keck IRTT, DSBP

COO Detector Activities
Roger Smith
2010-01-27
Current Themes
Delta Doped
CCD demo
COO Detector Activities
2
2010-01-27
Precision Projector
Galaxy shape
measurement
for Weak
Lensing
Wide field
Imaging
0.5%Super
novaPhoto
metry
NIR
Wavefront
Sensing
10ppm
relative
photometry(Ex
oPlanets)
Spectroscopy
3
Sponsors (indicated in black)
COO Detector Activities
JPL DRDF … LBNL (DOE)
Precision Projector
LBNL (DOE),
JDEM (NASA)
Weak Lensing
2010-01-27
SN
Photometry
LBNL (DOE)
Beichman
(JPL DRDF+,
NASA ROSES-SAT?)
Transit
Photometry
J.Johnson (CIT)
Caltech
IRIS-OIWFS (TMT)
NIRES,
NIR WFS
DBSP-Red
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.
2010-01-27
5
Delta Doped CCD demo on P60
COO Detector Activities
2010-01-27
• 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?)
CCD in
picture
frame
Idea 2.
Alternate
transition
card
location
Corner
bolt
threade
d into
frame
ALN
Metal frame presses on FG only where there is underlying Al Nitride
7
IR Spectroscopy
COO Detector Activities
2010-01-27
• 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.
2010-01-27
9
DBSP-R
QE Scenario
COO Detector Activities
2010-01-27
and ITO
250µm
thick
• 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
2010-01-27
•
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
Snout containing
long cold baffle and
cold JH filter
2010-01-27
Mounting
flange
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
2010-01-27
• 1Kx1K FoV is only 2
arcsec; used for
acquisition.
H2RG
• Window progressively
reduced to 4x4 pixels.
2048
Acquisition region ~ 1k × 1k
14×14
recapture
window
4×4 guide
window 2 mas/pix
2 arcsec
2048
• 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.
13
Noise vs speed measurements
COO Detector Activities
2010-01-27
• 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
2010-01-27
•
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
2010-01-27
• 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.
Spatial Noise v/s Effective Exp Time (91% Duty Cycle)
Masking off high dark current pixels
H2RG Spatial Noise for 91% Duty Cycle
6
Spatial Noise (e-)
5
4
3
2
no pixel masking
high DC 1/3 masked-off
1
high DC 2/3 masked-off
0
100
1000
10000
Effective Exp Time (s)
• 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-ofrange values ("1" for good pixels).
• Multiply the original Fowler-91% images sets by each mask.
• Calculate noise statistics on delta images, using "out-ofrange" pixel value rejection on top of the usual outlier
rejection (for CR).
16
17
SNAP CCD testing (pending)
COO Detector Activities
2010-01-27
• 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
2010-01-27
• 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
2010-01-27
• 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
2010-01-27
21
Progress to date
COO Detector Activities
2010-01-27
Primary mirror assembled in
sling mount
Secondary mirror procured.
Mount is in shop.
Bench thermal control system built and tested.
Masks procured
and sample
measured with
electron
microscope; 6
axis mask stage
and integrating
sphere in hand.
22
Exoplanet Transits
COO Detector Activities
2010-01-27
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.