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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211

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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