Detector chain calibration strategy for the Euclid flight IR H2RGs

Abstract

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.

Pre-launch optical verification of the Euclid NISP instrument and comparison with simulated images

“…The GC requires an accurate redshift of 𝜎 𝑧 /(1+ 𝑧) ≤ 0.001 that will be provided by the spectroscopic channel of the NISP (Near-Infrared Spectrometer and Photometer) instrument and its three grisms, one blue grism (920-1300 nm) and two red grisms (1254-1850 nm). In this paper, we focus on the NISP optical assessment referring to two different ground-test campaigns [1,5]. One held at the Laboratoire d'Astrophysique de Marseille (LAM) in January 2020, aiming at validating the performance of the NISP flight model, and the second held at the Centre Spatial de Liege (CSL) in 2021 to verify the performance of the payload module (PLM) which comprises the Euclid instruments coupled to the Euclid telescope and its mechanical structure.…”

Euclid Near Infrared Spectro-Photometer: spatial considerations on H2RG detectors interpixel capacitance and IPC corrected conversion gain from on-ground characterization

“…For this purpose, Euclid NISP H2RG flight detectors have been individually and thoroughly characterized at CPPM during a whole year, varying parameters such as temperature, flux level, bias, illumination history, etc. to cover varied flight configurations 13 at the price of producing 500 TB of raw data. From initial analyses, several parameters such as IPC, persistence and conversion gain have shown large spatial variations and interdependence.…”

Random telegraph signal (RTS) in the Euclid IR H2RGs

“…The calibration campaign at CPPM (Flight Model (FM) calibration campaign) was scheduled in blocks of 4 SCS tested in parallel in two identical cryostats, each test block lasting more than 1.5 months to complete, and coming now to its end with the final testing of the 4 Flight Spare SCAs. The description of the overall test campaign as well as the overall calibration strategy are presented in two additional Euclid papers of this conference (see [5] and [6]). For the follow-up study of the effect of random telegraph signal (RTS) and noise (RTN) in the Euclid infrared H2RGs, we analysed data from all 16 Flight SCAs tested at CPPM together with data from additional tests on two non-flight SCAs at ESA's European Space Research and Technology Centre (ESTEC) and at CPPM.…”