1 M. Auvergne. Natal October 2004 Instrument performances. Signal perturbations: Radiations....
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Transcript of 1 M. Auvergne. Natal October 2004 Instrument performances. Signal perturbations: Radiations....
1
M. Auvergne. Natal October 2004
Instrument performances.
•Signal perturbations:Radiations.Scattered light.ACS.Temperature.Readout electronic.
•Calibrations and ground based corrections.
•Performances on the two channels. Based on lab calibrationsand simulations with the instrument model
Michel Auvergne: Instrument scientist
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M. Auvergne. Natal October 2004
Aperture photometry
PF CCD image and apertures of selected targets
PF channel: for each target an optimalaperture (best S/N) is chosen among256 predefined apertures.
AS channel: an optimal apertureis computed for each target.
AS target image and aperture. QuickTime™ et un
décompresseur TIFF (LZW)sont requis pour visionner cette image.
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M. Auvergne. Natal October 2004
Radiations.
Depends on the shielding which is thicker than 10 mm in most directions.With 10 mm aluminium no e-, only p+Ep > 50 MeV.Perturbations inside the SAA.
Time spent in the SAA ~ 4%Max flux ~ 4000 p+/cm2/sec.Number of charges in an impact ~ 6000 e-
Data acquisition interrupted on the planet finding channel for flux larger than 300 p+/cm2/sec
Number of glitches in an aperture during an exposure in the SAA.AS ~ 0-3PF ~ 10
See Leonardo talk
Protons flux (AP8 min) function of time
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M. Auvergne. Natal October 2004
Scattered Light from the earth
Depends on the Line Of Sight (LOS)
For a LOS orthogonal to the orbit planethe SL is ≤ 1 e-/px/sec and reach100 e-/px/sec for a depointing of 12 degrees
Variations of the maximum SL level on 150 days for several LOS.
The background is measured on board on the two channels.200 background windows on the PF channel.10 background windows on the AS channel.
QuickTime™ et undécompresseur TIFF (LZW)
sont requis pour visionner cette image.
Background light curve.Ordinate unit e-/px/sec.
SL
Zodiacal light
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M. Auvergne. Natal October 2004
Attitude Control System.
Four orbital components (orbit period and harmonics), due to gravity torque and magnetic field, plus a random component.
The main photometric effect comes from theI/O of the image from the aperture (side effect)for AS and from frontiers effect on PF channel.
Spectrum of the x component of the ACS jitter
PF: Frontiers effect on colored photometry
AS: side effect due to image jitterJitter~0.06 px
QuickTime™ et undécompresseur TIFF (LZW)
sont requis pour visionner cette image.
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M. Auvergne. Natal October 2004
Temperature.
Photometric variations comes from: Quantum efficiency (100-500 ppm/K) Readout Gain (20 ppm/K) Readout Offset (500 ppm/K)
The offset is measured on board.The CCDs temperature is stabilizedat -40 C with white fluctuations of 0.005 C.
The orbital amplitude of readout electronicsis less than 0.3 K
Orbital temperature variations of the readout electronic
Annual amplitude variations of the readout electronic
Total amplitude in the light curve.Porb -> A< 20 ppm Harmonics < 2 ppm
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M. Auvergne. Natal October 2004
Calibrations.
Corrections are based on ground-based (CCDs), and on-board calibrations and Housekeeping (temperatures and voltages).•Ground based calibrations. CCDs Temperature sensitivity
PRNUGainFull Well capacityTraps and bright pixels.Polarisation voltagesLinearityDark current (before and after irradiation)
Readout electronicsTemperature sensitivityGainReadout noiseLinearity
•On-board calibrations will be used also to define parametrization of the flight software (see Leonardo’s talk). Full well capacity map
QuickTime™ et undécompresseur TIFF (LZW)
sont requis pour visionner cette image.
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M. Auvergne. Natal October 2004
Corrections: Scattered light
On the AS channel,the background is measured in 50*50 pixels windows close to the target, with a binning of 5*5 pixels. Substraction is madeon board.
On the PF channel, the background is measuredin 10*10 pixels windows. Substraction is made onground.The measurement precision is 5%.The residual noise is the background photon noise.
QuickTime™ et undécompresseur TIFF (LZW)
sont requis pour visionner cette image.
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M. Auvergne. Natal October 2004
Corrections: ACS Jitter.
On the AS channel the jitter effectis very small. The periodic componentscan be reduced by a factor 2.
On the PF channel the frontiers effectsare efficiently reduced.
More details in Fabio’s talk.
Blue: light curve with jitter fluctuations only.Black: light curve after correction.
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M. Auvergne. Natal October 2004
QuickTime™ et undécompresseur TIFF (LZW)
sont requis pour visionner cette image.
ordinate adu/exposure
Raw AS light curves.
AS: raw light curve for a 6 mag. StarBackground corrections are made on board QuickTime™ et un
décompresseur TIFF (LZW)sont requis pour visionner cette image.
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M. Auvergne. Natal October 2004
QuickTime™ et undécompresseur TIFF (LZW)
sont requis pour visionner cette image.
PF Light curve
PF white light curve with background removed. Missing data are due to the SAA crossing. Ordinate adu/exposure.
QuickTime™ et undécompresseur TIFF (LZW)
sont requis pour visionner cette image.
PF raw light curves for a 14 mag. starBlue curve: blue LCRed curve: red LCGreen curve:green LCBlack curve: background
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M. Auvergne. Natal October 2004
Brazilian contribution.
Leonardo Pinheiro da Silva (thesis)Calibrations processing. (See following talk)
Fabio de Oliveira Fialho (thesis)Aperture definition and ACS corrections.(See following talk)
Eduardo Costa da Silva (post-doc)Photometric corrections, in particular background gradientsTools for statistical analysis of the signal.
Claudia Angeli (post-doc)Tools for statistical analysis of the signal.MMI, tbc
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M. Auvergne. Natal October 2004
Estimated White noise budget error:
0
2
4
6
8
5 6 7 8 9 10 11
White noise on 5 days
Photons noise (ppm on 5 days)
mv
Red: total noiseBlue: photons noise
0
0,0002
0,0004
0,0006
0,0008
0,001
0,0012
10 11 12 13 14 15 16 17
Noise for 1h integration
photon noise PF 1h
mv
Dominant noise: readout Dominant noise: jitter+readout+background
Asteroseismology Planet Finding
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M. Auvergne. Natal October 2004
Global Budget error.
AS White noise 5 d. Orbital components
Comment
mv = 6.
Teff = 6250.
0.62 N0: 20, 12 10, 6
N1: 6,4,3,2
H1: corrections reduce amplitude
by a factor 3
PF White noise 1h Orbital components
mv=14
Sp. Type: K
2.2E-4 N0: 120 ppm
N1: 60 ppm
H1: corrections reduce amplitude
by a factor 2.
mv = 15.5
Sp. Type: K
7.4E-4 120 ppm