Measuring a Charge-Coupled Device Point Spread Function: Euclid Visible
  Instrument CCD273-84 PSF Performance
  In this paper we present the testing of a back-illuminated development Euclid
Visible Instrument (VIS) Charge-Coupled Device (CCD) to measure the intrinsic
CCD Point Spread Function (PSF) characteristics using a novel modelling
technique. We model the optical spot projection system and the CCD273-84 PSF
jointly. We fit a model using Bayesian posterior probability density function,
sampling to all available data simultaneously. The generative model fitting is
shown, using simulated data, to allow good parameter estimations even when
these data are not well sampled. Using available spot data we characterise a
CCD273-84 PSF as a function of wavelength and intensity. The CCD PSF kernel
size was found to increase with increasing intensity and decreasing wavelength.
