SITR: FORCAST
description
Transcript of SITR: FORCAST
SITR: FORCAST
February 19, 2010
Cornell University
Herter
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FORCAST Status• FORCAST is up and running in lab at DOAF!• Kudos to the FORCAST team
George Gull, Chuck Henderson, Justin Schoenwald Joe Adams, Luke Keller
• Schedule 2/05 Fri Shipped via FedEx Custom Critical 2/07 Sun Arrived at DOAF parking lot 2/08 Mon Unpack & prep for cool down 2/10 Wed FORCAST to LN2 2/11 Thu FORCAST to LHe 2/12 Fri Full cold soaked, working nominally
4/07 Wed Start of mini line-ops 4/23 Fri TA Characterization/First Light
Flight
Most Procedures in Place
• Signed off Vacuum and Leak
Check Warm Test Cold Test CWR Installation PI Rack Installation On-Aircraft Cryogen Fill CWR Removal
• Not yet signed Safe to Mate In-flight access
• Operational Mini line-ops plan First light plan Line ops plan
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Airworthiness document signed off as well.
Photos: Loading for Shipment
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Photos: In DAOF lab
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Calibration boxElectronics
Pump out
Cooling down
Lessoned Learned• In general, everything has gone rather well• Chris has done a great job in outfitting the lab
Tools, pumps, etc But check your H/W and tools: do you have specialty items? No H/W stock room (nuts, bolts, etc)
• No real problems with Safety and QA Mainly in observational mode, updating procedures Remember safety shoes You can’t roll crane under load Make sure you load certify your cart!
• Operational issue Access to instrument/lab requires planning Must have 2 team members + 1 USRA person present
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Optimizing FORCAST
• Tweaks to optimize signal-to-noise ratio Bias: Can increase G (good) and G (bad) Chop frequency: Influences1/f noise contributions Frame rate: Affects read noise contribution Mux gain: Affects read noise contribution
(high/low capacitance – low cap best)
• Optimization depends upon background photon flux G is both bias and background dependent
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1
RNntSGGn
tSG
N
S
pixbckpix
src
Ssrc = source photon rate
Sbck = background (ph/sec/pix)t1 = 1/ (frame rate)npix = source area (in pixels)RN = read noiseS/N = signal-to-noise (one read)
Fore Optics
• Simulate on-sky (faint) source Chop and “Nod” Set and regulate source T
(e.g. T = 2 K)
• Checks system with “real” source
Warm & cold throughput
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-20 -10 0 10 20-100
-50
0
50
Pixel
Sig
nal
Line Plot (129,124) - (179,124)
2 4 6 8
0
10
20
30
Distance (pixels)
Sig
nal
Radial Plot at ( 144.42, 124.31)
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0.5 1.0 1.5 2.0
20
40
60
80
100
120
detbias
SN
R_g
LWC LoCap (dT = 5C)
Optimizing Bias
• Upper left: S/N vs. bias for LWC low capacitance (low background) mode
30 micron + neutral density filter• Upper right: S/N vs. bias for
LWC in high capacitance (high background) mode
38 micron filter• Lower left: S/N vs. well depth
for LWC hi-cap mode sigLevel in DN
0.8 1.0 1.2 1.4 1.6 1.8 2.0150
200
250
300
detbias
SN
R_g
LWC HiCap (dT = 10C)
2000 4000 6000 8000 10000 12000
100
200
300
sigLevel
SN
R_g
LWC HiCap (dT = 10C)
6800 < sigLevel < 10700
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Cornell Non-DAOF activities• Prep for new LWC detector (GFY10-11)
New fan-out board New detector cabling Modify test dewar for array checkout FPGA and S/W mods for running array
• Documentation updates/generation (GFY10-11) Based on DAOF and flight results
• Installation and testing of LWC array (GFY11) Different multiplexor (and size) from current array
• Response to issues arising from first light flights (GFY10-11) Update FORCAST operations S/W Update data acquisition procedures Update data reduction pipeline Miscellaneous hardware updates due to unforeseen issues?
Final Comments
• We’re ready to go
• Plan to keep FORCAST cold for next two weeks Further parameter optimization Occasional “funnies” we want to track down Testing of IMC Fine tuning (setting of parameters, quick look <->
FORCAST communications, etc.)
• Back at Cornell Will look into digital bias control
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