<html dir="ltr"><head> <meta http-equiv="Content-Type" content="text/html; charset=Windows-1252"> <style id="owaTempEditStyle"></style><style title="owaParaStyle"></style> <meta content="MSHTML 6.00.6000.21366" name="GENERATOR"> </head> <body ocsi="x"> <div style="FONT-SIZE: x-small; COLOR: #000000; DIRECTION: ltr; FONT-FAMILY: Tahoma"> <div><a></a>Dear Gaters<a></a>, </div> <div><font face="tahoma"></font> </div> <div><font face="tahoma">A question related<a></a> to my<a></a> question from<a></a> yesterday<a></a>, </font></div> <div><font face="tahoma"><a></a><font face="tahoma">When</font> 2 brothers<a></a> volume are crossing<a></a>, what's<a></a> happening at<a></a> the crossing<a></a> point. </font></div> <div><font face="tahoma"><a></a><font face="tahoma">Here</font> is<a></a> a quick example<a></a> of what<a></a> I mean<a></a>, with<a></a> a mother<a></a> box having<a></a> 2 daughters<a></a> volume Castor and Pollux<a></a></font></div> <div><font face="tahoma"> <div><font face="tahoma">/gate<a></a>/motherbox<a></a>/daughters<a></a>/name<a></a> Castor </font></div> <div><font face="tahoma">/gate<a></a>/motherbox<a></a>/daughters<a></a>/insert cylinder<a></a></font><font face="Tahoma" color="#000000" size="2"><br> /gate<a></a>/Castor/geometry<a></a>/setHeight<a></a> 20. mm<br> /gate<a></a>/Castor/geometry<a></a>/setRmin<a></a> 0. mm<br> /gate<a></a>/Castor/geometry<a></a>/setRmax<a></a> 5. mm</font></div> <div><font face="tahoma">/gate<a></a>/Castor/placement/setTranslation<a></a> +2. -0. 0. mm</font></div> <div><font face="tahoma"></font> </div> </font></div> <div><font face="tahoma">/gate<a></a>/motherbox<a></a>/daughters<a></a>/name<a></a> Pollux<a></a></font></div> <div><font face="tahoma">/gate<a></a>/motherbox<a></a>/daughters<a></a>/insert cylinder<a></a></font><font face="Tahoma" color="#000000" size="2"><br> /gate<a></a>/Pollux<a></a>/geometry<a></a>/setHeight<a></a> 20. mm<br> /gate<a></a>/Pollux<a></a>/geometry<a></a>/setRmin<a></a> 0. mm<br> /gate<a></a>/Pollux<a></a>/geometry<a></a>/setRmax<a></a> 5. mm</font></div> <div><font face="tahoma">/gate<a></a>/Pollux<a></a>/placement/setTranslation<a></a> -2. -0. 0. mm</font></div> <div><font face="tahoma"></font> </div> <div><font face="tahoma"><a></a><font face="tahoma">these</font> volumes should<a></a> have a big<a></a> overlap<a></a> at<a></a> the center of motherbox<a></a>. </font></div> <div><font face="tahoma"></font> </div> <div><font face="tahoma"><a></a><font face="tahoma">Now</font> what's<a></a> occuring<a></a> when<a></a> a particle<a></a> pass<a></a> through<a></a> the middle of motherbox<a></a> ? </font></div> <div><font face="tahoma">Is the particle<a></a> inside<a></a> of Pollux<a></a> ? </font> </div> <div><font face="tahoma">Is the particle<a></a> inside<a></a> of Pollux<a></a> and Castor, and can<a></a> interact<a></a> with<a></a> both<a></a> </font></div> <div><font face="tahoma"><a></a><font face="tahoma">Does</font> the particle<a></a> belong<a></a> to the first volume it<a></a> crossed<a></a> ?</font></div> <div><font face="tahoma"></font> </div> <div><font face="tahoma"></font> </div> <div><font face="tahoma">If the last the volume always<a></a> on-top ? If yes<a></a>, this<a></a> answers<a></a> my<a></a> question from<a></a> yesterday<a></a>, </font></div> <div><font face="tahoma">the later-declared<a></a> volume being<a></a> on-top photons spend<a></a> more time inside<a></a> this<a></a> one and thus<a></a> scatter<a></a> more from<a></a> the last one. </font></div> <div><font face="tahoma"></font> </div> <div><font face="tahoma"><a></a><font face="tahoma">Cheers</font>, </font></div> <div><font face="tahoma">Maximilien </font></div> <div> </div> <div id="divRpF565765" style="DIRECTION: ltr"> <hr tabindex="-1"> <font face="Tahoma" color="#000000" size="2"><b>De :</b> gate-users-bounces@lists.opengatecollaboration.org [gate-users-bounces@lists.opengatecollaboration.org] de la part de MELISSAS Maximilien (SAFRAN) [maximilien.melissas-alten@safran.fr]<br> <b>Date d'envoi :</b> mercredi 26 février 2014 15:12<br> <b>À :</b> gate-users@lists.opengatecollaboration.org<br> <b>Objet :</b> [SUSPECTED SPOOFING] [Gate-users] (no subject)<br> </font><br> </div> <div></div> <div> <div style="FONT-SIZE: x-small; COLOR: #000000; DIRECTION: ltr; FONT-FAMILY: Tahoma"> <div dir="ltr"><font face="Tahoma" color="#000000" size="2"> <p><a></a>Dear Gaters<a></a>,</p> <p>I am<a></a> facing<a></a> an issue I don't<a></a> understand<a></a>, with<a></a> my<a></a> current<a></a> description of my<a></a> setup, it<a></a> seems<a></a> that<a></a> the X rays scattering<a></a> depends<a></a> on the order<a></a> in which<a></a> volumes have been declared<a></a> </p> <p> </p> <p>To mimic<a></a> the CT scan of a composite material<a></a> (I am<a></a> using<a></a> Gate<a></a> to understand<a></a> a CT-Scan setup used<a></a> for Aeronautical<a></a> part testing<a></a>), I am<a></a> introducing<a></a> a periodic<a></a> network of carbon<a></a> fiber<a></a> along<a></a> each<a></a> direction in my<a></a> test phantom<a></a> (Let’s<a></a> call these<a></a> direction 1, 2, 3)</p> <p> </p> <p>If I check the branches ComptVolName<a></a> and RayleighVolName<a></a> in the Hit Tree<a></a>, there<a></a> is<a></a> always<a></a> one direction producing<a></a> more scattering<a></a>. However<a></a>, whatever<a></a> the rotation of the phantom<a></a>, the later-declared<a></a> direction is<a></a> always<a></a> the one producing<a></a> the most<a></a> scattered<a></a> hits.</p> <p><a></a>Here is<a></a> a pseudo phantom.mac<a></a></p> <p>/gate<a></a>/world/daughters<a></a>/name<a></a> epoxyBox<a></a></p> <p>#Define<a></a> an epoxy<a></a> box,</p> <p>/gate<a></a>/epoxyBox<a></a>/daughters<a></a>/name<a></a> CCylinder1<a></a></p> <p>#Define<a></a> and rotate<a></a> an array<a></a> of carbon<a></a> Cylinder<a></a> using<a></a> Repeater<a></a></p> <p>/gate<a></a>/epoxyBox<a></a>/daughters<a></a>/name<a></a> CCylinder2<a></a></p> <p>#Define<a></a> and rotate<a></a> an array<a></a> of carbon<a></a> Cylinder<a></a> using<a></a> Repeater<a></a></p> <p>/gate<a></a>/epoxyBox<a></a>/daughters<a></a>/name<a></a> CCylinder3<a></a></p> <p>#Define<a></a> and rotate<a></a> an array<a></a> of carbon<a></a> Cylinder<a></a> using<a></a> Repeater<a></a></p> <p> </p> <p>All the Carbon<a></a> cylinders<a></a> are copy-pasted<a></a> and I change only<a></a> the rotation along<a></a> X/Y/Z . After<a></a> running the simulation, if I check which<a></a> volumes produces<a></a> the most<a></a> scattered<a></a> hits (from<a></a> Hits/CompVolName<a></a> and Hits/RayleighVolName<a></a>) the volume producing<a></a> the most<a></a> scattered<a></a> hits is<a></a> CCylinder3<a></a> whatever<a></a> the rotation of the epoxyBox<a></a> </p> <p>If now<a></a> I declare<a></a> the CCylinder<a></a> in a different<a></a> order<a></a> i.e<a></a></p> <p>/gate<a></a>/epoxyBox<a></a>/daughters<a></a>/name<a></a> CCylinder3<a></a></p> <p>#Define<a></a> and rotate<a></a> an array<a></a> of carbon<a></a> Cylinder<a></a> using<a></a> Repeater<a></a></p> <p>/gate<a></a>/epoxyBox<a></a>/daughters<a></a>/name<a></a> CCylinder1<a></a></p> <p>#Define<a></a> and rotate<a></a> an array<a></a> of carbon<a></a> Cylinder<a></a> using<a></a> Repeater<a></a></p> <p>/gate<a></a>/epoxyBox<a></a>/daughters<a></a>/name<a></a> CCylinder2<a></a></p> <p>#Define<a></a> and rotate<a></a> an array<a></a> of carbon<a></a> Cylinder<a></a> using<a></a> Repeater<a></a></p> <p><a></a>Now the CCylinder<a></a> producing<a></a> the most<a></a> scattered<a></a> hits is<a></a> CCylinder<a></a> 2 (whatever<a></a> the rotation of the epoxy<a></a> box)</p> <p>I made all the rotation testing<a></a> with<a></a> few photons (around<a></a> 100 000) to save<a></a> Computing<a></a> time, and I ran<a></a> another<a></a> orientation with<a></a> 10 000 000 photons to be<a></a> sure I am<a></a> not seeing<a></a> statistical<a></a> fluctuations</p> <p> </p> <p>Am I misunderstanding<a></a> the meaning<a></a> of the Rayleigh/ComptVolName<a></a> (actually<a></a>, how is<a></a> this<a></a> leaf<a></a> filled<a></a> when<a></a> a photon has been scattered<a></a> several<a></a> times)? Is it<a></a> another<a></a> feature<a></a> that<a></a> I don’t<a></a> understand<a></a> or am<a></a> I facing<a></a> a bug?</p> <p> </p> <p><a></a>Cheers,</p> <p>Maximilien</p> <p> </p> <p>--</p> <p>Maximilien MELISSAS<a></a><a></a></p> <p>Consultant, Alten<a></a><a></a> technology<a></a><a></a></p> <p>Image processing<a></a><a></a> for CT NDT<a></a><a></a> @ Safran composite</p> <p>http://www.alten.com</p> <p> </p> </font></div> </div> </div> </div> <p>#<br> " Ce courriel et les documents qui lui sont joints peuvent contenir des informations confidentielles, être soumis aux règlementations relatives au contrôle des exportations ou ayant un caractère privé. S'ils ne vous sont pas destinés, nous vous signalons qu'il est strictement interdit de les divulguer, de les reproduire ou d'en utiliser de quelque manière que ce soit le contenu. 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