Transient correction of the LW-ISOCAM data for low contrasted illumination
A. Coulais, A. Abergel;
AaAS, 2000, 141, 533
ABSTRACT:The detector of the Long Wavelength channel of the ISOCAM camera on-board the Infrared Space Observatory (ISO) presents systematic memory
effects of the response which can bias the photometry by a factor as high as
40%.
We show that, for uniform illumination, the non linear model developed by
\cite[Fouks and Schubert (1995)]{fou95} for the detector of PHT-S channel of the
ISOPHOT instrument allows us to describe the LW-ISOCAM response to upward and
downward steps of flux with an accuracy better than 1%.
For each pixel of the
detector, only two parameters have to be used.
These parameters are constant
over the whole life of ISO.
On the other hand, spatial variations from pixel
to pixel are significant.
We present an inversion method of the
Fouks-Schubert model.
Without any fitting and for low contrasted illumination, data
are corrected with a photometric accuracy of ~ 1%, which is typically ten
times better than previous methods.
We suggest that the same approach could
be used for others ISO detectors, and in the future for other
experiments.
KEYWORDS: instrumentation: detectors, methods: data analysis, methods: numerical
CODE: coulais2000