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</style><article id="node-361915" class="node node-logentry article ia-n clearfix" role="article"><header class="node-header"><h1 class="node-title" rel="nofollow">
<a href="https://logbooks.jlab.org/entry/3289171" rel="bookmark">CDC drift times</a>
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<p class="author-datetime">
Lognumber <a href="https://logbooks.jlab.org/entry/3289171" class="lognumber" data-lognumber="3289171">3289171</a>. Submitted by <a href="https://logbooks.jlab.org/user/davidl">davidl</a> on <time datetime="2014-07-03T17:18:13-0400" pubdate="pubdate">Thu, 07/03/2014 - 17:18</time>. </p>
<p class="last-update">
Last updated on <time datetime="2014-07-03T17:19:35-0400" pubdate="pubdate">Thu, 07/03/2014 - 17:19</time></p>
<table class="field-vitals"><tr><th>Logbooks: </th><td><a href="https://logbooks.jlab.org/book/hdcdc">HDCDC</a> <a href="https://logbooks.jlab.org/book/hdlog">HDLOG</a></td></tr><tr><th>Tags: </th><td><a href="https://logbooks.jlab.org/tag/detector">Detector</a></td></tr><tr><th>References: </th><td><a href="https://logbooks.jlab.org/entry/3288879">3288879 - CDC straw positions shifted in phi</a></td></tr></table></div>
<div class="logentry node-content">
<p>Code was added to emulate the fADC125 pulse time data using the window raw data acquired during the first BCAL/CDC cosmic run. The first incarnation does not yet implement the up sampling algorithm that will be in the FPGA. Instead, it just finds the first sample above threshold and uses the samples on either side of that to do a linear interpolation in order to get the threshold crossing time. An empirical shift of 170ns was included based on the measured time distribution of the first 147 events. The code implementing this was committed in svn revision 14025.</p>
<p>The attached screenshots indicate that timing information can be extracted from the fADC125 pulses that appears to be correlated with the drift distance (as it should be). The two circles drawn around the wires are to estimate the range of 4ns due to time of flight. The outer circle assumes tof=0 and the inner assumes tof=4ns. The yellow wires simply indicate "out of time" hits arbitrarily chosen to be drift times greater than 400ns. The black lines are from linear regression fits to the axial wire positions. No drift times are used for the fits.</p>
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