characterization of sim on sircus -...

Capabilities of NIST SIRCUS for Calibrations of SSI Vis-IR

Instruments

Steve Brown National Institute of Standards & Technology

Gaithersburg, MD

[email protected]; 301.975.5167

Answer: Ask LASP folks In 2005/2006, SIRCUS measured a SIM brassboard slit scatter function & ESR responsivity with Erik Richard, Jerry Harder and Colleagues from Laboratory for Atmospheric and Space Physics

(LASP), Boulder CO

• Spectral Irradiance Monitor (SIM) on SORCE – SIM is a Fèry prism spectrometer; only one optical element is needed to disperse and focus

the light onto four photodiode detectors and an electrical substitution radiometer (ESR).

2012 February Solar Spectral Irradiance (SSI) Variations Workshop 2

SIM Brassboard Slit Scatter Function

3 Solar Spectral Irradiance (SSI) Variations Workshop 2012 February

J. W. Harder, G. Thuillier, E. C Richard, et al., “The SORCE SIM Solar Spectrum Comparison with recent observations,” Solar Phys. 263, 3-24 (2010).

Grey lines – ray trace model

ESR Efficiency Results


Net result was that the radiometric response of the SIM instrument needs to be increased by a factor of 1.013 across the 258 nm to 1350 nm regime.

J. W. Harder, G. Thuillier, E. C Richard, et al., “The SORCE SIM Solar Spectrum Comparison with recent observations,” Solar Phys. 263, 3-24 (2010).

Presenter

Presentation Notes

Our interpretation these results is that the beam had shifted off the center of the bolometer between Ti:S and KTP OPO measurements. Not corrected because we did not do a vertical map. Vertical map done prior to CTA OPO and 200 um shift noted and corrected for.

SSI Workshop 1, September 2006

Worthwhile repeating the measurements


Solution: NIST loaned LASP an L-1 Stnds&Technol cryogenic radiometer and a Traveling SIRCUS system

Contact: Dave Harber, LASP, [email protected]

Presenter

Presentation Notes

Note on uncertainties: Laser stable to better than 0.1 %, power known to 0.1 %, window T ~ 0.1 % and SIM ESR ? But combined standard uncertainty of ~0.2 % achievable.

NIST SIRCUS Capabilities for SSI Measurements in the Reflected Solar Regime

• Introduction to SIRCUS

• What do we need the facility to do? – Available irradiance

– Uncertainty requirements

• Can SIRCUS achieve irradiance levels and uncertainties required for SSI climate change sensors?


Facility for Spectral Irradiance and Radiance responsivity Calibrations using Uniform Sources


• Develop broadly tunable laser systems to replace – Fixed frequency laser systems for scale

derivations

– Lamp-monochromator systems for detector calibrations

NIST Radiant Flux (Power) Uncertainties

— Extend the spectral region of low uncertainty; — Extend to irradiance and radiance responsivity

Coupling Tunable Lasers with Cryogenic Radiometers Scale Derivations

Historically QE measured at a few points and interpolated using a physical

model developed at NIST

• Developed for the 405 nm to 920 nm spectral region

• Uncertainties tend to be much larger outside this spectral region

With SIRCUS, we can 1. directly measure and fit the

quantum efficiency of Si trap detectors

2. extend the spectral coverage beyond the Si region

0.975

0.980

0.985

0.990

0.995

1.00

400 500 600 700 800 900 1000

ηe

λ [nm]

0.960

0.965

0.970

0.975

0.980

0.985

0.990

0.995

1.00

300 400 500 600 700 800 900 1000

EQE

Wavelength (nm)

2012 February 8 Solar Spectral Irradiance (SSI) Variations Workshop

SIRCUS

• Lasers determine the spectral coverage

• Detectors determine the uncertainties ultimately achievable


2012 February Solar Spectral Irradiance (SSI) Variations

Workshop 10

Optical Power: Lasers v. Lamp Monochromator Systems

0.01

0.1

1

10

200 400 600 800 1000 1200 1400 1600 1800M

onoc

hrom

ator

Out

put F

lux

(Pow

er) [

µW]

Wavelength (nm)

840 nm

600 nm 985 nm

1270 nm

1385 nm

420 nmArgon Mini-Arc

100 W Quartz-Halogen Lamp

NIST Lamp-Monochromator SIRCUS

1000 mW 1 µW

SIRCUS: 106 times more power

Does SIRCUS provide enough Irradiance?

Does SIRCUS provide enough Irradiance? SIRCUS irradiance levels (in a 2 inch beam) compared with

solar levels (in a 10 nm bandpass)

Linear Plot ETR ASTM E-490 vs. Wehrli WMO

0200400600800

1000120014001600180020002200

0 0.5 1 1.5 2 2.5 3 3.5 4

Wavelength micrometers

Spec

tral

Irra

dian

ce W

*m-2

*mic

ron-1

11 Solar Spectral Irradiance (SSI) Variations

Workshop 2012 February

E-490 (10 nm bp) v SIRCUS (5 cm diameter beam)

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

200 400 600 800 1000 1200

Wavelength /nm

Irra

dia

nce

/(W

/m2)

SSI Uncertainty Requirements for Climate Studies


Workshop 12

TRUTHS Requirements for SSI: < 0.1 % (k=1)

Can SIRCUS achieve the required uncertainty? How are the uncertainties validated?

NPOESS SIM instrument: relative uncertainty of 0.01 % and a combined absolute Uncertainty of < 0.5 % from 200 nm to 2400 nm. Erik Richard, et al.

CLARREO: solar reflected radiation 0.3 % (k=2)

SIRCUS Propagated Uncertainties (Si region)

Distance Aperture Area Uniformity exit port (radiance) ref plane (irradiance)

Detector Responsivity

I-V Gain factor Laser

Reference Detector

V

0.075 % (k=2)

Validating SIRCUS Uncertainties Development of Imaging Radiometers

Howard Yoon, David Allan, & colleagues, NIST

Advanced Pyrometer 1 Gold-point Blackbody

2012 February 13 Solar Spectral Irradiance (SSI) Variations

Workshop

Radiance Responsivity of the Absolute Pyrometer 1 (AP1) and Spectral Radiance from the Gold-Point Blackbody


400 500 600 700 800 900 100010-14

10-12

10-10

10-8

10-6

10-4

10-14

10-12

10-10

10-8

10-6

10-4

1337.33 K

Spe

ctral

Radi

ance

, L [

W/(c

m2 sr)

nm

]

Radi

ance

Res

pons

ivity

, SL [

A/W

/(cm

2 sr) ]

Wavelength [ nm ]

Howard Yoon, NIST

( ) ( ) ( ),PlanckS A L T R dλ λ λ= ∫

Melting and Freezing Cycles of the Gold-point Blackbody


Workshop 15

0 200 400 600 800 1000 1200 14001320

1330

1340

1350

1360

1370

T AP1 [

K ]

Time [ min ]

Howard Yoon, NIST

AP-1 Measurements

Temperature Determination of a Gold-point Blackbody Source

1337.1 1337.2 1337.3 1337.4 1337.5 1337.6 1337.79.990x10-11

1.000x10-10

1.001x10-10

1.002x10-10

1.003x10-10

1.004x10-10

1.005x10-10

1.006x10-10

1.007x10-10

TT900.15 % (k=2) in Radiance Resp.120 mK

1337.54 K1337.33 K

Phot

ocur

rent

[ A

]

Temperature [ K ]


H. Yoon, NIST

Radiometric

T90=International Temperature Scale of 1990

Acknowledge: SIRCUS Personnel • Keith Lykke, Leader

• SIRCUS Staff

– Steve Brown, Ping Shaw, Allan Smith

• Contributors

– George Eppeldauer, Transfer Standard Detectors

– Joe Rice & Jeanne Houston, Primary Optical Watt Radiometer (POWR)

– Colleen Jenkins, Mike Lin, Technical Support


Conclusions • SIRCUS has both the flux levels and the uncertainties (from

210 nm to 1.6 µm) required to support characterization and calibration of Solar Spectral Irradiance sensors

• Demonstrated success looking at a SIM Breadboard instrument at NIST and work currently underway at LASP

Things Dave Harber has been up to at LASP with SIRCUS lasers and L-1 cryo radiometer

• Previously: – Used the SIRCUS lasers to measure the flight TSIS SIM Fery prism

transmission from 211-2400 nm • This is a measurement of the Fresnel reflection and Aluminum reflection

losses in the Fery prism – Using the SIRCUS lasers and the Cryogenic Radiometer, we calibrated

the TSIS SIM electrical substitution radiometer (ESR) from 211 nm to 2400 nm

• Currently: – Using the SIRCUS lasers to calibrate the wavelength scale of the SIM

flight instrument and to measure the instrument response function as a function of wavelength and pointing, from 211 nm to 2400 nm

• Up Next: – Use the SIRCUS lasers and the Cryogenic Radiometer to calibrate the

end-to-end radiometric sensitivity of SIM, from 211 nm to 2400 nm


characterization of sim on sircus -...

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