According to 

</font><p><font size="2">
<ul>
<li> <tt> ESO-327242, Integrating Instrument Performance in the Quality Control Process - X-shooter </tt>
<li> <tt> VLT-SPE-ESO-14650-3323, X-SHOOTER Technical Specification </tt>
</ul>
</font><p><font size="2">
The detector non-linearity is specified to be < 1% in the dynamic range
of 10-100000e-, which corresponds to 64000 ADU. 
For the NIR-arm 1.0% is specified.

</font><p><font size="2">
Given the <a href="http://www.eso.org/observing/dfo/quality/XSHOOTER/qc/detmon_qc1.html#a_linearity"> 
history of detector monitoring</a>, the UVB/VIS non-linearity is based on the 
central parts (1000 x 1000 pixel) of imaging flats illuminated up to 65000 ADU 
in the central part (although other regions of the chips might be saturated due to 
an illumination gradient). The measured non-linearity is extrapolated to the saturation level 
of 65535 ADU. 
<br>
The NIR-arm non-linearity is based on a smaller window (200 x 40 pixel) 
matching an order in the spectroscopic echelle flat. 
Flats up to 42000 ADU are used (at counts > 42000 ADU, the detector starts to extrapolate the signal)
The non-linearity is given at
a reference level of 10000 ADU.