.. _VisGainModel:

======================
Vis Gain Model Product
======================

Metadata
______________________

+------------------------------------------------+----------------------------------------------------------------------------------------------+
| Data product name                              | DpdVisGainModel                                                                              |
+------------------------------------------------+----------------------------------------------------------------------------------------------+
| Data product custodian                         | VIS                                                                                          |
+------------------------------------------------+----------------------------------------------------------------------------------------------+
| Name of the Schema file                        | .. raw:: html                                                                                |
|                                                |                                                                                              |
|                                                | `euc-vis-GainModel.xsd <https://gitlab.euclid-sgs.uk/ST-DM/ST_DataModel/-/blob/10.1.2/ST_DM_ |
|                                                | Schema/auxdir/ST_DM_Schema/dpd/vis/euc-vis-GainModel.xsd>`_                                  |
+------------------------------------------------+----------------------------------------------------------------------------------------------+
| Processing Element(s) creating/using the data  | Gain Model                                                                                   |
| product                                        |                                                                                              |
+------------------------------------------------+----------------------------------------------------------------------------------------------+
| Processing function using the data product     | VIS                                                                                          |
+------------------------------------------------+----------------------------------------------------------------------------------------------+

Proposed for inclusion in EAS/SAS
==========================================
.. PFUsingStart

Yes

.. PFUsingEnd

Data product elements
=====================
+--------------+----------------------------------------------+
| Header       | object of type sys:genericHeader             |
+--------------+----------------------------------------------+
| Data         | object of type vis:visFileContainerData      |
+--------------+----------------------------------------------+
| QualityFlags | object of type dqc:sqfPlaceHolder            |
+--------------+----------------------------------------------+
| Parameters   | object of type ppr:genericKeyValueParameters |
+--------------+----------------------------------------------+
   
Detailed description of the data product
========================================
.. DetailedDescStart

Gain model is a JSON file containing a dictionary with one gain value in e-/ADU per quadrant.

The calibration pipeline consists in measuring the ratio of the mean signal versus square of the
standard deviation fluxes differences of two flat field pair. 

The gain can also be derived from the photon transfer curves (PTC). 
This second method is used as a validation of the calibration.
 
This flat field has been corrected from bias.
As we are at low fluxes, it is not necessary to correct from non-linearity and brighter-fatter.

See https://euclid.roe.ac.uk/dmsf/files/17670/view for more detail.

**Name of file:**

``EUC_VIS_MDL-GAIN__[YYYYMMDDThhmmss.s]Z.json``

where the date is the production date.

.. DetailedDescEnd