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Dear John and all,<br>
<br>
I will not be able to attend today's meeting. After went through
John's slides, I have a couple of comments:<br>
<br>
1. Please take into account the difference of attenuation of
Cherenkov photons going different directions in the quartz. Without
this, our optimization may not be valid for realistic condition.<br>
<br>
2. I understand John's argument about flat mirror and
three-segmentation designs. I simply treat it as the limitation from
the readout segmentation. Same argument is also true for the choice
of water with lower refractive index. In contrast with the flat
mirror design that will clearly increase the needs of readout area,
the three-segmentation design solves the problem by folding the
imagine in three pieces. This will clearly make the pattern more
complicated. My question to John is, can you demonstrate the
effectiveness of this design with the present of background and
other events?<br>
<br>
3. If we indeed need smaller readout segmentation, the Hamamatsu
H9500 has 3 mm pixels. The drawbacks are that the cost will be
pretty much doubled and the PMTs can not be treated as CLAS12's
spare units any more.<br>
<br>
Nevertheless, nice work John!<br>
<br>
BTW, a sample of MCP-PMT from Argonne will arrive soon - in a couple
of weeks. Carl and I are working on setting up the test stand.<br>
<br>
Best regards,<br>
Yi<br>
<br>
<br>
<div class="moz-cite-prefix">On 8/28/2014 4:47 PM, Baptiste Guegan
wrote:<br>
</div>
<blockquote
cite="mid:EEA9837E0C1BAE4BA87A24EF7754D9589B5B4A31@OC11EXPO29.exchange.mit.edu"
type="cite">
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<div style="direction: ltr;font-family: Tahoma;color:
#000000;font-size: 10pt;"><font color="black" face="Tahoma"
size="2"><span style="font-size:10pt;" dir="ltr">Dear all,<br>
<br>
We'll have our PID meeting tomorrow at 1:30 pm. If you would
like to present or discuss something, let me know and we'll
add it to the agenda which will appear here:</span></font><br>
<font color="black" face="Tahoma" size="2"><span
style="font-size:10pt;" dir="ltr"><a class="moz-txt-link-freetext" href="https://halldweb1.jlab.org/wiki/index.php/August_29,_2014_PID_Upgrade">https://halldweb1.jlab.org/wiki/index.php/August_29,_2014_PID_Upgrade</a>
<br>
<br>
Best<br>
Baptiste</span></font><br>
<br>
<br>
<br>
</div>
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</pre>
</blockquote>
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