This plot monitors QC parameter darklevel of the IFS-arm 
for a selected range of DIT
derived from SPHERE_irdifs_cal_dark template 
and processed by the sph_isf_dark recipe. 
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<ul>
<li>DIT=2, NDIT=40
<li>DIT=8, NDIT=25
<li>DIT=30, NDIT=15
</ul>

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Box (4) shows a linear dependence of the dark level with exposure time.
The relation is (2015-04-01) 
</font><p><font size="2">dark [ADU]  = -6 + 10.2 * DIT 
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Box (5) shows the IFS optical benchen temperature as function of time and 
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Box (6) shows the dependence of the dark level on the IFS optical bench temperature.