== P3.22	Instrument flat field, detector linearity and bad pixels == 
•	**Phase**		:	3  
•	**Status**		: 	Draft	 
•	**Category**		: 	Daytime calibration (C3)
•	**Recurrence**	: 	every day, with setup on request.
•	**Duration**		: 	20 minutes per configuration
**Description**
•	Instrument flat field, detector linearity, and bad pixels. 
**Prerequisites**
**Procedure**
•	Use the calibration flat-field source.
•	This calibration is performed illuminating the detector uniformly using the instrument FF lamp, for each filter. 
•	It is expected that the detector FF depends on filters, final accumulated charge in the pixels. Thus, a series of exposures will be taken at different count levels (realized via ND filters and/or DIT) for each filter setup. In this case, the template takes the background frames automatically. Comparing different count rates at constant DIT will also yield a linearity map of the detector. 
**Success criteria**
•	95% luminous uniformity at large scale.
•	99% luminous uniformity at pixel-to-pixel scale 10-2.
•	Large scales filtered out, only small detector scale will remain. Effect of the large-scale flat field on DBI (rescaling in flux & wavelength) has negligible impact on DBI performances.
**Notes**
•	Same as activity 7.9 in AD4
**LBTO support**
•	Support from LBTI/LBTO?
**Associated SHARK-NIR personnel**
•	JF, LM, MdP
**Date performed and by whom**