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<p class="MsoNormal">Dear GATE users,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">As part of my bachelor thesis, I’m currently modelling few different collimators to verify the best one for our system. (regarding spatial resolution and geometric efficiency)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am stuck at the last one, which is the converging (or diverging, depending on the size of the object) in two dimensions, meaning e.g. fan-beam in x-y direction.
<o:p></o:p></p>
<p class="MsoNormal">I have tried many things without success. <o:p></o:p></p>
<p class="MsoNormal">The main problem is the overlap of two daughters and the logic of the spherical repeater which GATE offers.<o:p></o:p></p>
<p class="MsoNormal">However when trying this (see textfile in the dropbox) I found out, that using more than 1 repeat in phi direction, the first copy is shifted with certain offset from the y-z plane.
<o:p></o:p></p>
<p class="MsoNormal"><br>
Does anyone had made any experiences with modelling this type of collimator? Is there another option to create a collimator with a spherical centered focalpoint?<o:p></o:p></p>
<p class="MsoNormal">Why does the spherical repeater start with a off set (= exactly the angle set) but only in one direction (eg. If phi has an off set, theta won’t, see screenshot “PhiAngle 10deg, 1 repeat Phi, ThetaAngle 10 with no offset”)?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Please find some screenshots regarding this issue in my dropbox:<o:p></o:p></p>
<p class="MsoNormal"><a href="https://www.dropbox.com/sh/9hc05h1xoelx050/AADdaJV85OM7iwI2uQwBVcJna?dl=0">https://www.dropbox.com/sh/9hc05h1xoelx050/AADdaJV85OM7iwI2uQwBVcJna?dl=0</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks a lot for your help<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best regards<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Milad Mesri<br>
<br>
<o:p></o:p></p>
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