<html>
  <head>
    <meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
  </head>
  <body bgcolor="#FFFFFF" text="#000000">
    Hi Alex,<br>
    <br>
    A few weeks ago, Eugene mentioned that you were going to perform
    additional simulations about the radiation levels in the tagger hall
    so we could settle on the racks placement. Did you have a chance to
    look into this?<br>
    <br>
    Thanks and best regards,<br>
    Fernando<br>
    <br>
    <br>
    On 12/9/2013 10:56 AM, Fernando J Barbosa wrote:
    <blockquote cite="mid:52A5E82D.50706@jlab.org" type="cite">
      <meta content="text/html; charset=UTF-8" http-equiv="Content-Type">
      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">
        <meta content="text/html; charset=UTF-8"
          http-equiv="Content-Type">
        <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">
          <meta content="text/html; charset=UTF-8"
            http-equiv="Content-Type">
          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 &lt;<a moz-do-not-send="true"
                  href="mailto:barbosa@jlab.org">barbosa@jlab.org</a>&gt;

                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, &lt;n&gt; =
                              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 &lt;<a
                                moz-do-not-send="true"
                                href="mailto:barbosa@jlab.org">barbosa@jlab.org</a>&gt;




                              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 &lt;<a
                                              moz-do-not-send="true"
                                              href="mailto:barbosa@jlab.org">barbosa@jlab.org</a>&gt;





                                            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>
                                                  </blockquote>
                                                  <br>
                                                </div>
                                              </div>
                                            </blockquote>
                                          </div>
                                          <br>
                                        </div>
                                      </blockquote>
                                      <br>
                                    </div>
                                  </div>
                                </div>
                              </blockquote>
                            </div>
                            <br>
                          </div>
                        </blockquote>
                        <br>
                      </div>
                    </div>
                  </div>
                </blockquote>
              </div>
              <br>
            </div>
          </blockquote>
          <br>
          <br>
          <fieldset class="mimeAttachmentHeader"></fieldset>
          <br>
          <pre wrap="">_______________________________________________
Halld-tagger mailing list
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:Halld-tagger@jlab.org">Halld-tagger@jlab.org</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="https://mailman.jlab.org/mailman/listinfo/halld-tagger">https://mailman.jlab.org/mailman/listinfo/halld-tagger</a></pre>
        </blockquote>
        <br>
        <br>
        <fieldset class="mimeAttachmentHeader"></fieldset>
        <br>
        <pre wrap="">_______________________________________________
Halld-tagger mailing list
<a moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:Halld-tagger@jlab.org">Halld-tagger@jlab.org</a>
<a moz-do-not-send="true" class="moz-txt-link-freetext" href="https://mailman.jlab.org/mailman/listinfo/halld-tagger">https://mailman.jlab.org/mailman/listinfo/halld-tagger</a></pre>
      </blockquote>
      <br>
    </blockquote>
    <br>
  </body>
</html>