A New Signal Estimator from the NIR Detectors of the Euclid Mission

Kubik, B.; Barbier, R.; Chabanat, E.; Chapon, A.; Clémens, J. C.; Ealet, A.; Ferriol, S.; Secroun, A.; Serra, Benoit; Smadja, G.; Tilquin, A.

doi:10.1088/1538-3873/128/968/104504

Cited by 12 publications

(14 citation statements)

References 18 publications

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“…In practice we deduce it from the CDS noise estimated from the simulated timelines of correlated readout noise and impose σ white = CDS/ √ 2. The covariance matrix in the white noise approximation is computed following Kubik et al (2016). In terms of the signal contribution we have considered two cases: 1) dark conditions and 2) sky background on nominal Euclid flight operations.…”

Section: White and Correlated Readout Noise Covariance Matricesmentioning

confidence: 99%

“…2.2, (CNA, hereafter). In practice, the maximum likelihood flux estimate for 1) is obtained using equation 11 in Kubik et al (2016). For the CNA case the maximum likelihood flux estimate is obtained using a simple grid approach.…”

Section: On-board Flux Estimationmentioning

confidence: 99%

“…For each exposure, non-destructive frames containing the full array data (i.e., all the pixels) are read (without instrumental reset) at about 1 Hz and sent to the acquisition program. The set of frames, for a given exposure, forms a ramp and the total flux for the exposure can be computed for each pixel through the slope of the ramp via a simple linear fit (Rauscher et al 2012;Kubik et al 2016). The final uncertainties in the measured flux are given by the uncertainties in each of the frames, which are due both to the readout noise and the photon noise.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Euclid: Estimation of the Impact of Correlated Readout Noise for Flux Measurements with the Euclid NISP Instrument*

Munoz

Macías-Pérez

Secroun

et al. 2021

PASP

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The Euclid satellite, to be launched by ESA in 2022, will be a major instrument for cosmology for the next decades. Euclid is composed of two instruments: the Visible (VIS) instrument and the Near Infrared Spectromete and Photometer (NISP). In this work we estimate the implications of correlated readout noise in the NISP detectors for the final in-flight flux measurements. Considering the multiple accumulated (MACC) readout mode, for which the UTR (Up The Ramp) exposure frames are averaged in groups, we derive an analytical expression for the noise covariance matrix between groups in the presence of correlated noise. We also characterize the correlated readout noise properties in the NISP engineering grade detectors using long dark integrations. For this purpose, we assume a (1/ f ) α -like noise model and fit the model parameters to the data, obtaining typical values of σ = 19.7 +1.1 −0.8 e − Hz −0.5 , f knee = 5.2 +1.8 −1.3 × 10 −3 Hz and α = 1.24 +0.26 −0.21 . Furthermore, via realistic simulations and using a maximum likelihood flux estimator we derive the bias between the input flux and the recovered one. We find that using our analytical expression for the covariance matrix of the correlated readout noise we diminish this bias by up to a factor of four with respect to the white noise approximation for the covariance matrix. Finally, we conclude that the final bias on the in-flight NISP flux measurements should still be negligible even in the white noise approximation, which is taken as a baseline for the Euclid on-board processing.

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Section: White and Correlated Readout Noise Covariance Matricesmentioning

confidence: 99%

Section: On-board Flux Estimationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Euclid: Estimation of the Impact of Correlated Readout Noise for Flux Measurements with the Euclid NISP Instrument*

Munoz

Macías-Pérez

Secroun

et al. 2021

PASP

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“…Baseline The in-flight information about the flux (See Ref. 6 for the definition of the slope computation and the associated quality factor (QF) of the fit used in NISP) transmitted to the ground is constrained by telemetry/day budget. None of the group ADCu values is transmitted to the ground in science observation modes.…”

Section: Summary Of the Flight Runs 2017-2018mentioning

confidence: 99%

Detector chain calibration strategy for the Euclid flight IR H2RGs

Barbier¹,

Buton²,

Clémens³

et al. 2018

High Energy, Optical, and Infrared Detectors for Astronomy VIII

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Euclid is an ESA mission to map the geometry of the Dark Universe with a planned launch date in 2021. 1 Two primary cosmological probes, weak gravitational lensing and baryonic acoustic oscillations, are implemented through a VISible imager (VIS) and a Near-Infrared Spectrometer and Photometer (NISP). The ground characterization of the NISP Flight Sensor Chip Systems (SCS) followed by the pixel response calibration aims to produce all informations to correct and control the accuracy of the signal. This work reports on the ground characterization of the NISP detector chain. The detector and electrical effects are likely to generate statistical fluctuations and systematic errors on the final flux measurement. The analysis strategies to maintain the pixel relative response accuracy within 1% is proposed in this work. The Euclid NISP test flow is presented and the main concerns of the detector chain calibration, such as non-linearity, charge trapping and de-trapping are discussed on the basis of the analysis of the flight detectors characterization data.

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“…This quality factor is described in details elsewhere. 11 It is derived for each ramp and each pixel with a view to validating the calculated flux. Figure 4, left, shows the normalized histogram of QF for scs2 for an incoming flux of 52 e/s.…”

Section: Pixel Selectionmentioning

confidence: 99%

Euclid flight H2RG IR detectors: per pixel conversion gain from on-ground characterization for the Euclid NISP instrument

Secroun¹,

Barbier

Buton

et al. 2018

High Energy, Optical, and Infrared Detectors for Astronomy VIII

Self Cite

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Euclid is a major ESA mission for the study of dark energy planned to launch in 2021. Euclid will probe the expansion history of the Universe using weak lensing and baryonic acoustic oscillations probes. A survey of 15,000 deg 2 of the sky with the instrument NISP (Near-Infrared Spectro-Photometer), in the 900-2100 nm band, will give both the photometric and spectrometric redshifts of tens of millions of galaxies. The 16 H2RG detectors of the NISP focal plane array are still being characterized at CPPM (Marseille). Already 16 out of 20 flight detectors have been tested and a straightforward analysis done. Performance of the dedicated test benches-in particular control of flux and temperature-as well as an overview of the test flow will be presented. This paper will present methods and some preliminary results on two detectors focusing on the determination of a per pixel conversion gain.

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A New Signal Estimator from the NIR Detectors of the Euclid Mission

Cited by 12 publications

References 18 publications

Euclid: Estimation of the Impact of Correlated Readout Noise for Flux Measurements with the Euclid NISP Instrument*

Euclid: Estimation of the Impact of Correlated Readout Noise for Flux Measurements with the Euclid NISP Instrument*

Detector chain calibration strategy for the Euclid flight IR H2RGs

Euclid flight H2RG IR detectors: per pixel conversion gain from on-ground characterization for the Euclid NISP instrument

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