<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<div class="moz-cite-prefix">Hi Abdella,<br>
<br>
At high activities, your random coincidence rate should become
more important than your true coincidence rate, depending on your
coincidence time window, your minimum block coincidence, and your
multiple coincidence policy (killAll, takeAllGoods...).<br>
But you also need to take into account deadtime if you did not,
because at high activities it will favor random coincidences if
i'm not wrong, and so your NECR will decrease.<br>
<br>
Hope this helps,<br>
<br>
Vincent<br>
<br>
<br>
On 07/24/2013 09:02 AM, Abdella Mohammednur wrote:<br>
</div>
<blockquote
cite="mid:CAHTpmAooONH-ZZAWydJC7_mZZZ5FbSL+AsapO67nWmHs4LJhjA@mail.gmail.com"
type="cite">
<div dir="ltr">Dear all,
<div><br>
</div>
<div>I want to evaluate the noise equivalent count rate (NECR)
from singles. But when I draw the graph it is a kind of linear
(for activity from 5kBq/cc to 70 kBq/cc for NEMA phantom, 70
cm height and 20cm diameter). I made the following:</div>
<div>1. source type is back to back</div>
<div>2. True coinsidence count: If event Id of the two singles
are the same, they are consider as true (if there is no
scatter in the phantom) </div>
<div>3. scatter ( if there is scattering in the phantom)</div>
<div>3. random is estimated if two coincidence events have
different event ID</div>
<div><br>
</div>
<div>But the NECR graph is a straight line (linear) and couldn't
saturate at high activities. what should I do to calculate the
correct NECR from singles.</div>
<div><br>
</div>
<div><br>
</div>
<div>Thank you very much,</div>
<div><br>
</div>
<div>Abdella</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
<pre wrap="">_______________________________________________
Gate-users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Gate-users@lists.opengatecollaboration.org">Gate-users@lists.opengatecollaboration.org</a>
<a class="moz-txt-link-freetext" href="http://lists.opengatecollaboration.org/mailman/listinfo/gate-users">http://lists.opengatecollaboration.org/mailman/listinfo/gate-users</a></pre>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
Vincent Vandenbussche
Laboratoire IMNC
0169154471</pre>
</body>
</html>