<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Hi,</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
The fraction of accidental hits in the CCAL is relatively small <br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
so the impact of accidentals on the efficiency of Compton events <br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
is not significant, at least for the event selection I used.<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
The difference in efficiency was well below 1% (on the level of sensitivity of <br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
the MC sample I used) when the beam trip time was excluded (for some <br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
runs with the typical fraction of the beam off time )</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
At any rate, when Peter is done with his method, we can produce new hddm files <br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
for random triggers. The easiest way would be to accept or reject random triggers</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
in between SYNC events, where we read out TS scalers (I don't know how exactly <br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Peter is implementing this).</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Cheers,</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Sasha</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div id="appendonsend"></div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Primexd <primexd-bounces@jlab.org> on behalf of Alexander Austregesilo <aaustreg@jlab.org><br>
<b>Sent:</b> Thursday, January 21, 2021 5:25 PM<br>
<b>To:</b> Igal Jaegle <ijaegle@jlab.org><br>
<b>Cc:</b> primexd@jlab.org <primexd@jlab.org>; Peter Pauli (PGR) <p.pauli.1@research.gla.ac.uk><br>
<b>Subject:</b> [Primexd] Random trigger skims</font>
<div> </div>
</div>
<div class="BodyFragment"><font size="2"><span style="font-size:11pt;">
<div class="PlainText">Hi Igal,<br>
<br>
We have a plugin called randomtrigger_skim to filter out the random <br>
triggers from any evio input and convert them into the hddm format that <br>
can be mixed into the simulation by mcsmear. To be more realistic, we <br>
only accept random triggers that fall into a time period were the beam <br>
was actually on. The plugin takes this beam fiducial map into account, <br>
but it has to be generated beforehand. Peter Pauli (cc) was just working <br>
on an improved scheme for this extraction, maybe he can help you also <br>
for the PrimEx data.<br>
<br>
Once the fiducial map is ready, you just have to run the plugin over all <br>
evio files. Afterwards, we can concatenate the hddm skims from <br>
individual evio files so that we have one file per run.<br>
<br>
Before you have the fiducial map, you can also include the option <br>
`RANDSKIM:USEBEAM 0` into your config file to simply write out all <br>
random triggers. This serves already as a good approximation.<br>
<br>
Let me know if you have any questions,<br>
<br>
Alex<br>
<br>
_______________________________________________<br>
Primexd mailing list<br>
Primexd@jlab.org<br>
<a href="https://mailman.jlab.org/mailman/listinfo/primexd">https://mailman.jlab.org/mailman/listinfo/primexd</a><br>
</div>
</span></font></div>
</body>
</html>