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<div class="" style="word-wrap:break-word; line-break:after-white-space">Folks,
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<div class="">I have been looking at the recently cooked RG-K runs in the range from 5681-5990. The calibrations in</div>
<div class="">place for RG-K were based on my calibrations for run 5700. Looking at the flight times for charged</div>
<div class="">tracks in CTOF, about a third of the counters have the wrong flight time as can be seen in the attached</div>
<div class="">plots. The physical flight times for charged particles should be in the range up to ~4 ns. However, in</div>
<div class="">the present data about 1/3 of the counters have unphysically large flight times (values > 5 ns). This is</div>
<div class="">due to a problem in the P2P calibration for these counters. These events with the wrong P2P show up</div>
<div class="">at beta~0.2 and give rise to the background in chi2pid underlying the peak about zero.</div>
<div class=""><br class="">
</div>
<div class="">I expect this may be due to the fact that the data were calibrated before the DC geometry constants</div>
<div class="">were shifted and the cooked data include the DC geometry constants. This affects the path length </div>
<div class="">and hence the ST determination. If these changes, it can affect the CTOF timing. I am looking into</div>
<div class="">this.</div>
<div class=""><br class="">
</div>
<div class="">For now, I am proceeding by not using chi2pid or the EB PID assignment and doing my own PID.</div>
<div class="">I compute the TOF for CTOF shifting any flight times>4.5 ns by TRF and everything looks good for</div>
<div class="">all 48 CTOF counters. This is just an FYI for folks looking into this data. Let me know if you have</div>
<div class="">any questions. See the attached plots for more information.</div>
<div class=""><br class="">
</div>
<div class="">Regards,</div>
<div class="">Daniel</div>
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</div>
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***********************************************************************************</div>
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