CoRoT Satellite: Analysis of the In-Orbit CCD Dark Current Degradation

Gilard, O.; Boatella-Polo, Cesar; Dolado-Perez, J.C.; Auvergne, M.; Quadri, Gianandrea; Boutillier, M.

doi:10.1109/tns.2010.2044048

Cited by 15 publications

(8 citation statements)

References 11 publications

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“…The unavoidable imperfections of the above physical process and the corrections that are required to mitigate the resulting limitations have been studied by all manufacturers and scientific users of CCDs (e.g., Rodricks & Venkataraman 2005;Burke et al 2005), and especially at the occasion of every space instrument embarking one (e.g., Defise et al 1997;Lo & Srour 2003;Sirianni et al 2004;Schou 2004;Penquer et al 2009;Gilard et al 2010).…”

Section: Charge-coupled Devicesmentioning

confidence: 99%

“…Spatially, they are randomly distributed and appear as white dots in dark images. They create an extended tail in the dark current distribution, and this tail chiefly determines the dark signal non uniformity (DSNU; e.g., Gilard et al 2008Gilard et al , 2010.…”

Section: Hot Pixelsmentioning

confidence: 99%

“…Various dedicated solutions have been proposed by different authors (Hill et al 1997;Widenhorn et al 2007;Gilard et al 2010;Cai et al 2010, for example). Although this is not the purpose of the present work, we additionally mention the approach of Gomez Rodriguez et al (2009) and Burger et al (2011), who intended to not only correct for the dark signal but also to minimize the associated dark noise.…”

Section: Technical and Data Processing Solutions For Limiting The Effmentioning

confidence: 99%

“…They have been purchased in 2001 as part of the procurement of a batch of ten devices for the CoRoT astrometric space mission (Auvergne et al 2009), which has been developed a few years before PICARD and was also managed by the French Space Agency (CNES). The main reason for selecting a device of the 42−80 series for SODISM has been the similarity of the specifications and the project synergy with the CoRoT CCD program at the Laboratoire d'Études Spatiales et d'Instrumentation en Astrophysique (LESIA; Bernardi et al 2004;Buey et al 2005;Lapeyrere et al 2006;Gilard et al 2008Gilard et al , 2010.…”

Section: Unbalanced Haar Transformmentioning

confidence: 99%

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Dark signal correction for a lukecold frame-transfer CCD

Hochedez

Timmermans²,

Hauchecorne

et al. 2013

A&A

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Context. Astrophysical observations must be corrected for their imperfections of instrumental origin. When charge-coupled devices (CCDs) are used, their dark signal is one such hindrance. In their pristine state, most CCD pixels are cool, that is, they exhibit a low quasi-uniform dark current, which can be estimated and corrected for. In space, after having been hit by an energetic particle, pixels can turn hot, viz. they start delivering excessive, less predictable, dark current. The hot pixels therefore need to be flagged so that a subsequent analysis may ignore them. Aims. The image data of the PICARD-SODISM solar telescope require dark signal correction and hot pixel identification. Its E2V 42-80 CCD operates at −7.2• C and has a frame-transfer architecture. Both image and memory zones thus accumulate dark current during integration and readout time, respectively. These two components must be separated in order to estimate the dark signal for any given observation. This is the main purpose of the dark signal model presented in this paper. Methods. The dark signal time-series of every pixel was processed by the unbalanced Haar technique to timestamp when its dark signal changed significantly. In-between these instants, the two components were assumed to be constant, and a robust linear regression, with respect to integration time, provides first estimates and a quality coefficient. The latter serves to assign definitive estimates for this pixel and that period. Results. Our model is part of the SODISM Level 1 data production scheme. To confirm its reliability, we verified on dark frames that it leaves a negligible residual bias (5 e − ) and generates a small rms error (25 e − rms). We also examined the distribution of the image zone dark current. The cool pixel level is found to be 4.0 e − pxl −1 s −1 , in agreement with the predicted value. The emergence rate of hot pixels was investigated as well. It yields a threshold criterion at 50 e − pxl −1 s −1 . The growth rate is found to be on average ∼500 new hot pixels per day, that is, 4.2% of the image zone area per year. Conclusions. A new method for dark signal correction of a frame-transfer CCD operating near −10• C is described and applied. It allows making recommendations about the implementation and scientific usage of such CCDs. Moreover, aspects of the method (adaptation of the unbalanced Haar technique, dedicated robust linear regression) have a generic interest.

show abstract

Section: Charge-coupled Devicesmentioning

confidence: 99%

Section: Hot Pixelsmentioning

confidence: 99%

Section: Technical and Data Processing Solutions For Limiting The Effmentioning

confidence: 99%

Section: Unbalanced Haar Transformmentioning

confidence: 99%

See 2 more Smart Citations

Dark signal correction for a lukecold frame-transfer CCD

Hochedez

Timmermans²,

Hauchecorne

et al. 2013

A&A

View full text Add to dashboard Cite

show abstract

“…The unavoidable 'imperfections' of the above physical process and the corrections that are required to mitigate the resulting limitations have been studied by all manufacturers and scientific users of CCDs (e.g., Rodricks & Venkataraman 2005;Burke et al 2005), and especially at the occasion of every space instrument embarking one (e.g., Defise et al 1997;Lo & Srour 2003;Sirianni et al 2004;Schou 2004;Penquer et al 2009;Gilard et al 2010).…”

Section: Charge Coupled Devicesmentioning

confidence: 99%

Dark signal correction for a lukecold frame transfer CCD. Application to the SODISM solar telescope on board the PICARD space mission

Hochedez,

Timmermans,

Hauchecorne

et al. 2013

Preprint

View full text Add to dashboard Cite

Context. Astrophysical observations must be corrected for their imperfections of instrumental origin. When Charge Coupled Devices (CCDs) are used, their dark signal is one such hindrance. In their pristine state, most CCD pixels are 'cool', i.e. they exhibit a low, quasi uniform dark current, which can be estimated and corrected for. In space, after having been hit by an energetic particle, pixels can turn 'hot', viz. they start delivering excessive, less predictable, dark current. The hot pixels need therefore to be flagged so that subsequent analysis may ignore them. Aims. The image data of the PICARD SODISM solar telescope (Meftah et al. 2013) require dark signal correction and hot pixel identification. Its E2V 42-80 CCD operates at −7.2 • C and has a frame transfer architecture. Both image and memory zones thus accumulate dark current during, respectively, integration and readout time. These two components must be separated in order to estimate the dark signal for any observation. This is the main purpose of the Dark Signal Model presented in this paper. Methods. The dark signal time series of every pixel is processed by the 'unbalanced Haar technique' (Fryzlewicz 2007) in order to timestamp the instants when its dark signal is expected to change significantly. In-between those, both components are assumed constant, and a robust linear regression vs. integration time provides first estimates and a quality coefficient. The latter serves to assign definitive estimates for this pixel and for that period. Results. Our model is part of the SODISM Level 1 data production scheme. To check its reliability, we verify on dark frames that it leaves a negligible residual bias (5 e − ), and generates a small RMS error (25 e − rms). We also analyze the distribution of the image zone dark current. The cool pixel level is found to be 4.1 e − • pxl −1 • s −1 , in agreement with the predicted value. The emergence rate of hot pixels is investigated too. It legitimates a threshold criterion at 50 e − • pxl −1 • s −1 . The growth rate is found to be on average ∼500 new hot pixels per day, i.e. 4.2% of the image zone area per year. Conclusions. A new method for dark signal correction of a frame transfer CCD operating at only ca. −10 • C is demonstrated. It allows making recommendations about the scientific usage of such CCDs in space. Independently, aspects of the method (adaptation of the unbalanced Haar technique, dedicated robust linear regression) have a generic interest.

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Active collision avoidance manoeuvre design based on equidistant interpolation

Qi¹,

Jia²

2011

Acta Astronautica

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CoRoT Satellite: Analysis of the In-Orbit CCD Dark Current Degradation

Cited by 15 publications

References 11 publications

Dark signal correction for a lukecold frame-transfer CCD

Dark signal correction for a lukecold frame-transfer CCD

Dark signal correction for a lukecold frame transfer CCD. Application to the SODISM solar telescope on board the PICARD space mission

Active collision avoidance manoeuvre design based on equidistant interpolation

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