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Dear collaborators,<br>
<br>
At the last Cal Working group meeting we discussed ideas for
deciding which light guides with partial detachment should be
reglued. We also discussed the effort required to complete
simulations, which could provide some guidance about how to make
this decision. This question was further discussed at the Bcal
reconstruction meeting (see
<a class="moz-txt-link-freetext" href="https://halldweb1.jlab.org/wiki/index.php/BCAL_Reconstruction_Meeting_2013-05-23">https://halldweb1.jlab.org/wiki/index.php/BCAL_Reconstruction_Meeting_2013-05-23</a>).
It seems the simulations are not easily adapted to the question
before us and the long term stability of partially detached light
guides stability is uncertain in any case. Therefore, we have
decided to simply replace all light guides with detached surfaces.
This may be slightly more work, but clearly this is the time to do
any repairs.<br>
<br>
We have put together a draft plan for the rework on the wiki at
<a class="moz-txt-link-freetext" href="https://halldweb1.jlab.org/wiki/index.php/Light_Guide_Rework_Plan">https://halldweb1.jlab.org/wiki/index.php/Light_Guide_Rework_Plan</a>,
which we will refine and follow in the coming weeks. Feedback and
comments are welcome.<br>
<br>
Cheers, Elton.<br>
<div class="moz-forward-container"><br>
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-------- Original Message --------
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">Subject:
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<td>Re: [Halld-offline] BCAL software update</td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">Date: </th>
<td>Tue, 7 May 2013 10:47:36 -0600</td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">From: </th>
<td>Zisis Papandreou <a class="moz-txt-link-rfc2396E" href="mailto:Zisis@uregina.ca"><Zisis@uregina.ca></a></td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">To: </th>
<td>Will Levine <a class="moz-txt-link-rfc2396E" href="mailto:wlevine@gmail.com"><wlevine@gmail.com></a></td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">CC: </th>
<td>Elton Smith <a class="moz-txt-link-rfc2396E" href="mailto:elton@jlab.org"><elton@jlab.org></a>, David Lawrence
<a class="moz-txt-link-rfc2396E" href="mailto:davidl@jlab.org"><davidl@jlab.org></a>, Andrei Semenov JLab
<a class="moz-txt-link-rfc2396E" href="mailto:semenov@jlab.org"><semenov@jlab.org></a>, Beni Zihlmann
<a class="moz-txt-link-rfc2396E" href="mailto:zihlmann@jlab.org"><zihlmann@jlab.org></a></td>
</tr>
</tbody>
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<br>
<br>
Hi Will:
<div><br>
</div>
<div>I will pout this item on the top of our agenda this Thursday
so we can discuss whether going with the full code is a good way
or maybe using a toy Monte Carlo. We have a few of those
kicking around in Regina.</div>
<div><br>
</div>
<div>Cheers, Zisis...</div>
<div><br>
<div>
<div>On 2013-05-07, at 10:02 AM, Will Levine <<a
moz-do-not-send="true" href="mailto:wlevine@gmail.com">wlevine@gmail.com</a>>
wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">I think what you are asking is that we
simulate a light loss in a<br>
specific area within a specific waveguide (rather than a
smaller light<br>
loss over the whole area of the waveguide). Is this correct?
This<br>
sounds non-trivial, but I'm not sure exactly how hard this
would be to<br>
implement in hdgeant, hopefully David can comment on this.<br>
<br>
As far as observing the effects on energy and position
resolution: the<br>
shower reconstruction code is not yet extensively tested or<br>
bulletproofed, but the total energy and the transverse
position are<br>
the easy quantities to calculate, so I think this will be
fine.<br>
Anything involving the timing or z-position is more iffy,
but it<br>
doesn't sound like you are worried about that.<br>
<br>
Will<br>
<br>
On Tue, May 7, 2013 at 8:28 AM, Elton Smith <<a
moz-do-not-send="true" href="mailto:elton@jlab.org">elton@jlab.org</a>>
wrote:<br>
<blockquote type="cite">Hi Will,<br>
<br>
Glad to hear that the software environment is getting
settled. I have a<br>
practical question that I hope you or someone can help out
with. We have run<br>
into problems with light guides detaching after gluing and
need to develop a<br>
plan for fixes. In particular we need to establish clear
guidelines for the<br>
technical staff about which light guides to reglue. Some
situations are<br>
clear such as complete or major detachments. In addition,
guides on the<br>
periphery of the array will be replaced since there is
clear access. A<br>
single light guide with partial detachment (say 10-20%) in
the middle of the<br>
array creates a conundrum. This situation will lead to a
light decrease in<br>
the affected area of about 10%. The guides are difficult
to pull off to<br>
begin with and cleaning the area before regluing is not
easy.<br>
<br>
We need to develop criteria over the next couple of weeks
for deciding on<br>
precisely which guides to replace. The small detachments
can affect both<br>
energy and position resolution. I assume the effect on
energy resolution<br>
will be small (10% loss of 20% area is a 2% effect), but
should be<br>
confirmed. The effect on transverse position resolution
might be more<br>
dramatic, since it will create asymmetries in the energy
profile<br>
distribution.<br>
<br>
My question is: can our present simulation study the
effects of partial<br>
light loss from areas on the light guide on energy and
position resolution?<br>
I assume this would be done with single photons and not be
complicated<br>
initially by multiple showers. I assume one would have to
modify hdgeant to<br>
implement the light loss because the information is lost
when the energy is<br>
collected into output channels.<br>
<br>
Thanks, Elton.<br>
<br>
Elton Smith<br>
Jefferson Lab MS 12H5<br>
12000 Jefferson Ave STE 16<br>
Newport News, VA 23606<br>
(757) 269-7625<br>
(757) 269-6331 fax<br>
<br>
<br>
On 5/6/13 8:16 PM, Will Levine wrote:<br>
<blockquote type="cite"><br>
I recently checked in some changes that enable the new
BCAL simulation<br>
and reconstruction code by default. This new code treats
ADC and TDC<br>
hits separately and does timewalk corrections, among
other things. In<br>
addition, the default BCAL clustering algorithm has been
switched from<br>
the KLOE algorithm to the IU algorithm.<br>
<br>
A few notes:<br>
<br>
When updating to the latest code, you must rerun the
simulation<br>
(mcsmear in particular) before running the
reconstruction. Old hddm<br>
files will not work properly with the new code.<br>
<br>
Analyzing REST files from the data challenge is still
possible, but<br>
you must use the -PDEFTAG:DBCALShower=KLOE option.<br>
<br>
Will<br>
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</blockquote>
<br>
<br>
</blockquote>
</blockquote>
</div>
<br>
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<div><font class="Apple-style-span"
color="#1d5091" face="Verdana" size="4"><br
class="Apple-interchange-newline">
Dr. Zisis Papandreou</font></div>
<div><font class="Apple-style-span" face="Verdana">Professor
of Physics, Ph.D, P.Phys.</font></div>
<div><font class="Apple-style-span" face="Verdana">---------------------------------------------------------</font></div>
<div><font class="Apple-style-span"
color="#929292" face="Verdana">Department of
Physics </font></div>
<div><font class="Apple-style-span"
color="#929292" face="Verdana">University of
Regina </font></div>
<div><font class="Apple-style-span"
color="#929292" face="Verdana">3737 Wascana
Parkway</font></div>
<div><font class="Apple-style-span"
color="#929292" face="Verdana">Regina, SK S4S
0A2 CANADA</font></div>
<div><font class="Apple-style-span" face="Verdana"><br>
</font></div>
<div><font class="Apple-style-span" face="Verdana"><b>Phone:
(306) 585-5379</b></font></div>
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<font class="Apple-style-span" color="#929292">Fax: (306)
585-5659</font>
<div><font class="Apple-style-span" color="#929292">Email:</font> <a
moz-do-not-send="true" href="mailto:zisis@uregina.ca">zisis@uregina.ca</a></div>
<div>
<div><font class="Apple-style-span" color="#929292"
face="Verdana">Website:</font> <a moz-do-not-send="true"
href="http://kronos.phys.uregina.ca/%7Ezisis/professional/">http://kronos.phys.uregina.ca/~zisis/professional/</a></div>
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