CALPRODUCT-VS-011: VIS Photon Transfer Curve (PTC)¶
Parent requirement¶
Scheduling¶
Weekly
Time-critical¶
No
Objective¶
Obtain the photon transfer curve (PTC / gain) for every detector quadrant.
Fulfilled by¶
Processing input¶
Ground Processing Input Data:
Data Description:
Processing method¶
Create a combined master flat for each illumination level. Create the photon transfer curves, and extract the gain from the pseudo-linear relation between variance and mean of the image pairs.
Processing output¶
Updated gains for each detector quadrant.
Required accuracy, constraints¶
TBW
Processing tools¶
TBW
Validation¶
The gains of the various quadrants in the VIS CCDs range between 3.30 and 3.70 e-/ADU. The gain is also slightly dependent on detector temperature.
If the gain of a quadrant changes by more than TBD %, then either the gain maps must be updated, or suitable adjustments made to the hardware (if possible, in flight).
Recovery¶
Update the gain maps, or take corrective measures.
Quality control parameters¶
DataModel: https://gitlab.euclid-sgs.uk/
Contact person¶
VIS instrument scientist