<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: arial,helvetica,sans-serif; font-size: 12pt; color: #000000'>I agree, 2 MeV looks suspicious. <br><br><div><span name="x"></span>-Eugene<span name="x"></span><br></div><br><hr id="zwchr"><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From: </b>"Dr. A.M. Sandorfi" <sandorfi@jlab.org><br><b>To: </b>"Eugene Pasyuk" <pasyuk@jlab.org><br><b>Cc: </b>"g14 run" <g14_run@jlab.org><br><b>Sent: </b>Wednesday, April 2, 2014 12:17:29 PM<br><b>Subject: </b>Re: [G14_run] Eloss values for g14<br><br>
<title>Re: [G14_run] Eloss values for g14</title>
<font face="Calibri, Verdana, Helvetica, Arial"><span style="font-size:11pt">Eugene, <br>
While there can be some discussion of the low energy acceptance limit, where the energy loss is quite large, my point was about much higher energies where the particles are essentially minimum ionizing. In that regime pions can’t loose less than 4.6 MeV when leaving the g14 IBC. (At lower energies they loose much more.) This discussion has come about following Dao’s tests of your Eloss which seem to show pion energy losses peaking at 2 MeV.<br>
<br>
Andy<br>
<br>
<br>
<br>
On 4/2/14, 12:00 PM, "Eugene Pasyuk" <<a>pasyuk@jlab.org</a>> wrote:<br>
<br>
</span></font><blockquote><font face="Arial"><span style="font-size:12pt">Andy,<br>
<br>
65 MeV protons at vertex will not be detected in CLAS. Minimum momentum of reliably reconstructed tracks for protons is at least 300-350 MeV/c. They have to get through roughly 5 m of air, six drift chambers and be detected in TOF counter. From that reconstructed by drift chambers momentum eloss works backwards to the vertex: ~1m of air, start counter IBC, the particle gains energy. <br>
<br>
-Eugene<br>
<br>
<hr align="CENTER" size="3" width="100%"></span></font><blockquote><span style="font-size:12pt"><font face="Helvetica, Verdana, Arial"><b>From: </b>"Dr. A.M. Sandorfi" <<a>sandorfi@jlab.org</a>><br>
<b>To: </b>"g14 run" <<a>g14_run@jlab.org</a>><br>
<b>Sent: </b>Wednesday, April 2, 2014 11:23:00 AM<br>
<b>Subject: </b>[G14_run] Eloss values for g14<br>
<br>
Eloss values for g14 </font></span><font face="Calibri, Verdana, Helvetica, Arial"><span style="font-size:11pt">Folks,<br>
<br>
Regarding ELOSS, the Tech Note (HDice_TN22) that I put together for Eugene can be downloaded from:<br>
<<a href="http://www.jlab.org/Hall-B/HDIce/technotes/HDice_TN22_IBC_dEdx.pdf" target="_blank">http://www.jlab.org/Hall-B/HDIce/technotes/HDice_TN22_IBC_dEdx.pdf</a>> .<br>
<br>
The Appendix at the end gives examples of explicit energy loss evaluations for pions and protons (a) near the low end of their acceptance (25 MeV for pions and 65 MeV for protons) and (b) at 1 GeV (~ minimizing ionizing for both). These were calculated for lab angles of 90 degrees where the material thicknesses are their least. The calculations assume events originate at the center of the target. As an extreme case, the Eloss from events coming from the outer edge of the HD nearest the detector would be down by the entries in the first two rows of the tables. There is no way a pion can loose less than 4.6 MeV by the time it exits the IBC and gets to the Start Counter.<br>
<br>
Andy</span></font><font face="Helvetica, Verdana, Arial"><span style="font-size:12pt"> <br>
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