The QC parameter qc_ron is not calculated by the pipeline but by a QC script. 
From the raw frame fits cube, five planes are extracted (plane 6 to 10), and 
for each pixel the stdev (out of five independent reads) is calculated. 
The median over all pixels stdev is taken. </font><p><font size="2">
The parameter <b>qc_ron</b> contains statistical noise, which is composed of a static detector readout
noise component of 2.47 ADU and a exposure time dependent component of </font><p><font size="2">

sqrt(counts / gain) </font><p><font size="2">

corresponding to the shot noise induced by the background radiation. 
In box (4) the function 2.47 + sqrt(-6 + 10.2 * DIT / 3.6) is overplotted. 

</font><p><font size="2">
The three reference setups (DIT=2, 8, and 30) are scored according to the dashed lines in boxes
1,2, and 3. All other setups are scored according to the non-linear arithmetic relation
indicated by the dashed curves in box 4. </font><p><font size="2">
<ul>
<li> upper threshold = sqrt((-6 + 10.2 * DIT)/3.6)+2.47  <b>-2.0-0.1*DIT</b>
<li> lower threshold = sqrt((-6 + 10.2 * DIT)/3.6)+2.47  <b>+3.0+0.1*DIT</b>
</ul>