CALPRODUCT-NI-013: NISP Reciprocity Failure¶
Parent requirement¶
Not yet in the CalCD-B
Scheduling¶
Once during PV phase. Possibly repeated in flight (TBD).
Time-critical¶
Best taken right after the absolute photometric standard.
Objective¶
Validate the reciprocity failure (flux-dependent nonlinearity, charge trapping) for each detector. Trapping and detrapping effects are poorly understood, impact photometric measurements, and exhibit strong spatial variations across detectors. This validation is a spot check to see whether anything has changed since the more extensive ground characterization, and to obtain similar measurements with real targets under in-flight conditions.
Trapping/detrapping is likely wavelength independent. However, in-flight and with all instrumental effects “turned on”, we must verify this assumption. Hence the procedure outlined below will be repeated for all three filters during PV phase. In case of repetition during routine phase, it is assumed that we execute the sequence in just a single filter.
Fulfilled by¶
Data volume¶
19008 MB (216 NISP-P exposures)
Processing input¶
Ground Processing Input Data: All calibration products to run the standard science pipeline (BPM, darks, flat, nonlinearity etc), reference measurement of standard star, RSR curves (relative spectral response of the system (mirrors, optics, instrument)
Data Description: NISP: 7*4*2*2 + 10*4*2 = 192 photo-MACC images
Processing output¶
Percentage or decade of flux reciprocity failure, if present. Comparison with a model prediction from ground characterization data. A warning must be triggered if the reciprocity failure deviates more than TBD % from the prediction.
Required accuracy, constraints¶
Flux level of sources can be measured, not affected by saturation, flux measurement comparison with and without extra background illumination
Processing tools¶
L1 science pipeline and absolute calibration pipeline, additional offline trend analysis of flux measurements
Quality control parameters¶
DataModel: https://gitlab.euclid-sgs.uk/
Contact person¶
NISP-P calibration scientist