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<div class="moz-cite-prefix">Hi Richard, <br>
<br>
I attached pictures of the Hall B downstream alcove from 2011
beam test run in Hall B taken from <br>
the preliminary report at the collaboration meeting in May of 2011
(page 8 in Jones et al , GlueX-doc-1759). <br>
The black box after the big flange with red HV cables is an
identical twin of the beam profiler that <br>
Elton's commissioning list included today. The Hall D active
collimator at that time was riding on top of the <br>
total absorption counter's translation table within a meter
downstream from the beam profiler. <br>
This beam profiler was present on the photon beamline just
upstream of the active collimator the whole time during the test.
<br>
And that is in addition to the main CLAS target far upstream which
must have been a few % of a radiation length. <br>
Based on UConn analyses, the active collimator worked well in
these conditions. Could you explain <br>
why you are sure that the active collimator worked well in Hall B
and it will not work in Hall D if there is <br>
an identical profiler in the beamline upstream of it?<br>
<br>
Hovanes <br>
<br>
<br>
From Elton's bullets with, I believe, your underlined comments:<br>
1. Require profile monitor to be installed and operational -- <u>where?
(cannot be upstream of active collimator)<br>
</u>....<br>
7. Compare with response of active collimator -- <u>cannot be
done with profile monitor installed<br>
<br>
<br>
<br>
<br>
</u><img src="cid:part1.01080101.00020004@gmail.com" alt=""> <img
src="cid:part2.01070004.04090304@gmail.com" alt=""><br>
<br>
On 11/11/2013 11:17 AM, Richard Jones wrote:<br>
</div>
<blockquote
cite="mid:CABfxa3TDm9nLdGr_HCWPwQk-xixhj4CTj2STeVVi69hGfkjvog@mail.gmail.com"
type="cite">
<div dir="ltr">Hello all,
<div><br>
</div>
<div>The photon beam working group meeting is taking place this
morning at 11:30EST. A draft agenda has been placed on the
wiki. Please change as needed.</div>
<div><br>
</div>
<div>-Richard J.</div>
</div>
<br>
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