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Hi Chris,
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<div class="">I think that what you are seeing is an artifact that originates in the visualisation system. To be sure that this is the case I suggest two potential ways:</div>
<div class=""> - Use a different visualisation system that uses ray tracing - which will demonstrate whether there are gaps;</div>
<div class=""> - Shoot ‘geantino’ test particles (which have no interactions) in a thin ring around the hole where you suspect that there is a problem. If you encounter the expected surfaces, all is good. I suggest to use a ring that is at least 10^-8 mm
larger in the inner radius, and up to 10^-3 mm maybe (or a bit larger). </div>
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<div class="">Best regards,<br class="">
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<div class="">John Apostolakis</div>
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<div class="">===================================================</div>
<div class="">John Apostolakis, EP Department, CERN</div>
<div class="">SFT (SoFTware for Experiments) Group</div>
<div class="">Office: Building 32/ room R-003 (ground floor), Mail: J27210</div>
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<div class=""><a href="mailto:john.apostolakis@cern.ch" class="">Email: john.apostolakis@cern.ch</a> Office Tel: +41-22-767-7239</div>
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<div class="">On 8 Nov 2019, at 16:06, Christopher Watanabe <<a href="mailto:chris.r.watanabe@gmail.com" class="">chris.r.watanabe@gmail.com</a>> wrote:</div>
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<div class="">Hello all, <br class="">
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I was visualizing a pinhole collimator I'm designing, and I noticed something strange that could effect experiments I run. I've defined my camera system and collimator as being aligned to the y-axis, where the pinhole is centered at (0,0,0). When I visualize
though, the axes are off by just the slightest amount, see below. <br class="">
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<div class=""><span id="cid:ii_k2q9g7mw0"><axes_offput.JPG></span></div>
<div class="">The ball in the middle is defined with the same radius as the pinhole, and since they are both aligned at (0,0,0), I expect the sphere to sit right inside the pinhole. However, there's a small offset. The strangest part is that every piece of
the collimator / camera system has 0 x or z translation (red and blue), which means this shouldn't be the case...<br class="">
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<div class="">Has anyone else experienced this? And should I be worried? <br class="">
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<div class="">Thanks! <br class="">
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<div class="">Chris<br class="">
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