<div dir="ltr">Hello Fernando,<div><br></div><div>I am spec'ing the Vbias supply capacity at 500mA to allow for the maximum SiPM draw current that is permitted by the bias voltage supply system. Initially we expect the average current to be around 15 mA at full intensity (2.2 uA electrons on 20 micron diamond) but that it will increase gradually over time due to radiation damage. To get the maximum current spec, I imagine the worst possible circumstances under which the radiation damage might accumulate faster than expected, and ask how much current could we sustain across all channels before the resolution and efficiency degrade significantly due to dark current. The answer to that is approximately 800uA per channel, which totals about 400mA from the supply. I rounded that up to 500mA. </div>
<div><br></div><div>-Richard Jones</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Dec 5, 2013 at 4:51 PM, Fernando J Barbosa <<a href="mailto:barbosa@jlab.org">barbosa@jlab.org</a>> wrote:<br>
<blockquote class="gmail_quote">Hi Richard,<br>
<br>
I looked at the specs and the bias supply current seems to be excessive at 500mA. What's the reason for this?<br>
<br>
Best regards,<br>
Fernando<div class="HOEnZb"><div class="h5"><br>
<br>
<br>
On 12/5/2013 3:33 PM, Richard Jones wrote:<br>
<blockquote class="gmail_quote">
Hello Alex,<br>
<br>
Here is a draft of the specs for the microscope readout dc power supplies. They can be a single unit for each of 3 levels, or a few lower-capacity supplies in tandem with the same total output capacity. Please request justification for any of the specs. One thing we do not spec here, but think would be useful, is separate delivery and sense terminals for each output. We have separate pins on the backplane connector for this purpose.<br>
<br>
<a href="http://zeus.phys.uconn.edu/wiki/index.php/Microscope_Electronics#Power_Supply_Requirements">http://zeus.phys.uconn.edu/<u></u>wiki/index.php/Microscope_<u></u>Electronics#Power_Supply_<u></u>Requirements</a><br>
<br>
-Richard Jones<br>
</blockquote>
<br>
</div></div></blockquote></div><br></div>