VIS: the visible imager for Euclid

Cropper, Mark; Pottinger, S.; Niemi, Sami-Matias; Denniston, James; Cole, R. S.; Szafraniec, Magdalena B.; Mellier, Y.; Martignac, J.; Cara, C.; Giorgio, A. M. Di; Sciortino, Andrea; Paltani, S.; Genolet, L.; Fourmand, J.-J.; Charra, M.; Guttridge, P.; Winter, B.; Endicott, J.; Holland, Andrew D.; Gow, Jason; Murray, Neil J.; Hall, D.; Amiaux, J.; Laureijs, R. J.; Racca, Giuseppe D.; Salvignol, Jean-Christophe; Short, A.; Alvarez, José Lorenzo; Kitching, Thomas D.; Hoekstra, Henk; Massey, Richard

doi:10.1117/12.2055543

Cited by 27 publications

(23 citation statements)

References 10 publications

(2 reference statements)

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“…The model is therefore also able to simulate multi-level clocking and other complex clocking schemes, such as trap pumping, [9][10][11][12][13] and its relation to charge loss. 14 While the initial purpose of C3TM is to deliver input to the radiation damage correction efforts for the VISual instrument 15 on ESAs Euclid mission, 16 the code has been made such that it can be easily be adapted to detectors for other instruments. This means that the code could be beneficial for other current or future space missions.…”

Section: Introductionmentioning

confidence: 99%

C3TM: CEI CCD charge transfer model for radiation damage analysis and testing

Skottfelt¹,

Hall

Dryer

et al. 2018

High Energy, Optical, and Infrared Detectors for Astronomy VIII

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Radiation induced defects in the silicon lattice of Charge Couple Devices (CCDs) are able to trap electrons during read out and thus create a smearing effect that is detrimental to the scientific data. To further our understanding of the positions and properties of individual radiation-induced traps and how they affect spaceborne CCD performance, we have created the Centre for Electronic Imaging (CEI) CCD Charge Transfer Model (C3TM). This model simulates the physical processes taking place when transferring signal through a radiation damaged CCD. C3TM is a Monte Carlo model based on Shockley-Read-Hall theory, and it mimics the physical properties in the CCD as closely as possible. It runs on a sub-electrode level taking device specific charge density simulations made with professional TCAD software as direct input. Each trap can be specified with 3D positional information, emission time constant and other physical properties. The model is therefore also able to simulate multi-level clocking and other complex clocking schemes, such as trap pumping.

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Section: Introductionmentioning

confidence: 99%

C3TM: CEI CCD charge transfer model for radiation damage analysis and testing

Skottfelt¹,

Hall

Dryer

et al. 2018

High Energy, Optical, and Infrared Detectors for Astronomy VIII

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“…Based on these two probes, Euclid will map out the underlying distribution of dark matter in the universe, as well as constrain the cosmic expansion history and therefore the equation of state parameter of dark energy. For each probe the telescope will simultaneously investigate, a separate instrument is being built: the VISual (VIS) instrument (Cropper et al 2014) for imaging in the optical, and the Near-Infrared Spectroscope and Photometer (NISP) instrument (Maciaszek et al 2014) for imaging and slit-less spectroscopy in the near infra-red (NIR). In order to achieve its scientific goals, the Euclid mission must be optimised in a way that balances the requirements of these two primary probes, with additional science goals.…”

Section: Introductionmentioning

confidence: 99%

Large-scale retrospective relative spectrophotometric self-calibration in space

Markovič¹,

Percival²,

Scodeggio

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We consider the application of relative self-calibration using overlap regions to spectroscopic galaxy surveys that use slit-less spectroscopy. This method is based on that developed for the SDSS by Padmanabhan et al. (2008) in that we consider jointly fitting and marginalising over calibrator brightness, rather than treating these as free parameters. However, we separate the calibration of the detector-to-detector from the full-focal-plane exposure-to-exposure calibration. To demonstrate how the calibration procedure will work, we simulate the procedure for a potential implementation of the spectroscopic component of the wide Euclid survey. We study the change of coverage and the determination of relative multiplicative errors in flux measurements for different dithering configurations. We use the new method to study the case where the flat-field across each exposure or detector is measured precisely and only exposureto-exposure or detector-to-detector variation in the flux error remains. We consider several base dither patterns and find that they strongly influence the ability to calibrate, using this methodology. To enable self-calibration, it is important that the survey strategy connects different observations with at least a minimum amount of overlap, and we propose an "S"-pattern for dithering that fulfills this requirement. The final survey strategy adopted by Euclid will have to optimise for a number of different science goals and requirements. The large-scale calibration of the spectroscopic galaxy survey is clearly cosmologically crucial, but is not the only one. We make our simulation code public on github.com/didamarkovic/ubercal.

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“…The Euclid Visible Instrument (VIS) will contain a focal plane of 36 e2v CCDs, each of 4k × 4k pixels, each 12 µm square [5][6][7]. Euclid VIS will perform weak gravitational lensing measurements, investigating shape changes in galaxies.…”

Section: Observing Lower Signals In Space Astronomymentioning

confidence: 99%

Challenges in photon-starved space astronomy in a harsh radiation environment using CCDs

et al. 2015

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The Charge Coupled Device (CCD) has a long heritage for imaging and spectroscopy in many space astronomy missions. However, the harsh radiation environment experienced in orbit creates defects in the silicon that capture the signal being transferred through the CCD. This radiation damage has a detrimental impact on the detector performance and requires carefully planned mitigation strategies.The ESA Gaia mission uses 106 CCDs, now orbiting around the second Lagrange point as part of the largest focal-plane ever launched. Following readout, signal electrons will be affected by the traps generated in the devices from the radiation environment and this degradation will be corrected for using a charge distortion model. ESA's Euclid mission will contain a focal plane of 36 CCDs in the VIS instrument. Moving further forwards, the World Space Observatory (WSO) UV spectrographs and the WFIRST-AFTA coronagraph intend to look at very faint sources in which mitigating the impact of traps on the transfer of single electron signals will be of great interest.Following the development of novel experimental and analysis techniques, one is now able to study the impact of radiation on the detector to new levels of detail. Through a combination of TCAD simulations, defect studies and device testing, we are now probing the interaction of single electrons with individual radiation-induced traps to analyse the impact of radiation in photon-starved applications.

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VIS: the visible imager for Euclid

Cited by 27 publications

References 10 publications

C3TM: CEI CCD charge transfer model for radiation damage analysis and testing

C3TM: CEI CCD charge transfer model for radiation damage analysis and testing

Large-scale retrospective relative spectrophotometric self-calibration in space

Challenges in photon-starved space astronomy in a harsh radiation environment using CCDs

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