image 18-October-2017 14:53:15

Sub-pixel scanning of the Euclid SCS detector

Date: 12 January 2016
Satellite: Euclid
Copyright: ESA

To reach its scientific objectives, Euclid must make photometric measurements in the near infrared wavelength range with exquisite accuracy. One possible contribution to the noise is the sub-pixel response which induces very small variations of the photo-response when the telescope point spread function size is comparable to a couple of pixels, as it is the case for Euclid.

As support to the Euclid mission, a test bench featuring a beam with F#10 numerical aperture has been commissioned to measure the photometric impact of the sub-pixel response variations in the Euclid CCD detector.

An F#10 beam projector has been installed on a 3-axis translation stage in front of the Euclid HAWAII-2RG detector maintained at a temperature of 100K with mK fluctuation. The fully automated system allows engineers to record frames at 1100 nm, 1550 nm and 1950 nm. The spot size is diffraction limited with an Airy function projected on the detector.

At 1550 nm, the radius of the first ring of the Airy function is around 1 pixel or 18 micron. For each position of the spot inside the pixel, the signal received by one of the pixels has been recorded.

This picture shows this response at a wavelength of 1550 nm. Each step scan is around 1.8 micron. The goal of this experiment is to evaluate the photometric impact of the intra-pixel variations.

 

 


Last Update: 18 February 2016

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