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Hi Hovanes,<br>
<br>
My plan is to use a mini MPOD with two modules, one is the familiar
8V and the other is a 120V. Both are Wiener MPODs and I can segment
into 6 TAGM backplane feeds. So, the controls are the same as the
rest of the Hall D MPODs. This solution will cost less than $15k. I
will distribute the plan shortly.<br>
<br>
Best regards,<br>
Fernando<br>
<br>
<br>
On 12/9/2013 10:51 AM, Hovanes Egiyan wrote:
<blockquote cite="mid:52A5E6F6.6010207@gmail.com" type="cite">
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<div class="moz-cite-prefix">Hi Richard, <br>
what type of controls is needed for these? Do we need to be able
to remotely <br>
control them, turn them on/off, power cycle them? <br>
Hovanes. <br>
<br>
On 12/09/2013 10:37 AM, Fernando J Barbosa wrote:<br>
</div>
<blockquote cite="mid:52A5E3B3.5020505@jlab.org" type="cite">
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Hi Richard,<br>
<br>
OK, looks good. I will look at options for the supplies.<br>
<br>
Thanks and best regards,<br>
Fernando<br>
<br>
On 12/9/2013 10:28 AM, Richard Jones wrote:
<blockquote
cite="mid:CABfxa3QLVFh7-c4hXrerYvFccsA+mZYDqg=TgPK4+2CB54yN5g@mail.gmail.com"
type="cite">
<div dir="ltr">Fernando,
<div><br>
</div>
<div>Our background study showed that we could continue to
function for 10 years of high-rate running without
annealing, just allowing the dark rate to increase at the
rate that was measured in Hall B and allowing the supply
current to increase. Under the zero-shielding scenario,
just leaving the electronics unshielded in the tagger
hall, we estimated that we would reach the point where we
would need to do something (eg. anneal or replace the
SiPM's) after 10 years of high-rate running. The usual
assumptions were applied (100 days of running per year,
standard 20 micron diamond, 12 GeV electrons at 2.2
microAmps). With shielding, we expect to reduce this
figure by a factor of 5-10 (the simulation gave a factor
around 8), so we should be able to run for the duration of
GlueX without annealing.</div>
<div><br>
</div>
<div>I agree with you that we can segment the supplies.
Each of them can be split up to 6 ways, because there are
6 identical backplanes in the system. The specs we posted
were for the total sum of all 6 backplanes.</div>
<div><br>
</div>
<div>-Richard J.</div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Mon, Dec 9, 2013 at 9:52 AM,
Fernando J Barbosa <<a moz-do-not-send="true"
href="mailto:barbosa@jlab.org">barbosa@jlab.org</a>>
wrote:<br>
<blockquote class="gmail_quote">
<div bgcolor="#FFFFFF" text="#000000"> Hi Richard,<br>
<br>
Certainly the rates in the tagger are higher but what
is your planning for annealing the SiPMs? I am just
curious given the higher rates.<br>
<br>
Regarding the power supplies, you mentioned the
possibility of having three supplies instead of one
for the whole system. Is it possible to consider
further segmentation? One channel per backplane? Do
you have a document that shows the whole system as
installed? The issue is also related to the space
available under the magnet.<br>
<br>
Best regards,<br>
Fernando
<div>
<div class="h5"><br>
<br>
<br>
On 12/6/2013 10:09 AM, Richard Jones wrote:
<blockquote type="cite">
<div dir="ltr">Fernando,
<div><br>
</div>
<div>These estimates for the BCal do not apply
to the TAGM, where the rates are much
higher. We can set up a meeting to discuss
this further if you feel we need it. We
worked out these rates back during the
design phase for the readout electronics,
and had them reviewed within the photon beam
working group. Also keep in mind that the
neutron flux is much higher in the tagger
hall than in the experimental hall. On the
other hand, the TAGM can operate efficiently
at much higher single-pixel rates than can a
calorimeter because it is not producing an
energy measurement, but only time, and the
photon statistics are high, <n> =
350-400 within a 15ns window. We are
shielding these electronics, but we only
expect to cut down the neutron flux by about
a factor 10-20 in this way. Alex Somov did
the neutron rates and shielding studies for
us, and can provide more details in this
regard.</div>
<div><br>
</div>
<div>-Richard J.</div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Fri, Dec 6, 2013
at 9:04 AM, Fernando J Barbosa <<a
moz-do-not-send="true"
href="mailto:barbosa@jlab.org">barbosa@jlab.org</a>>
wrote:<br>
<blockquote class="gmail_quote">
<div bgcolor="#FFFFFF" text="#000000"> Hi
Richard,<br>
<br>
In reference to the BCAL and taking Yi's
measurements in Hall A regarding
radiation damage, we settled on a
maximum of 10mA for 10 arrays or 160
cells (3mm x 3mm). This works out to
62.5uA per cell and your estimate is
higher by a factor greater than 10. What
is your plan for annealing the SiPMs?
Frequency?<br>
<br>
Did you look into any supplies that
might fit your requirements? I recall
that each backplane of the TAGM has a
single bias supply input, correct? This
would be important in considering a
multi-channel supply system. Please send
me your latest drawings on the TAGM
system and its installation in the
Tagger hall.<br>
<br>
Best regards,<br>
Fernando
<div>
<div><br>
<br>
<br>
On 12/5/2013 10:50 PM, Richard Jones
wrote:
<blockquote type="cite">
<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
moz-do-not-send="true"
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>
<div><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
moz-do-not-send="true"
href="http://zeus.phys.uconn.edu/wiki/index.php/Microscope_Electronics#Power_Supply_Requirements">http://zeus.phys.uconn.edu/wiki/index.php/Microscope_Electronics#Power_Supply_Requirements</a><br>
<br>
-Richard Jones<br>
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