<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> </head> <body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "> After a bit more of snooping around, the source particles are also generated with a call to the same function, which means that the inner radius of your source will be effectively ignored and you'll be left with a full cylindrical source. <div> </div> <div>You'll definitely need to fix the bug in the Geant4 code. <div> </div> <div> <div apple-content-edited="true"><span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; border-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "> <div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "> <div>Marc</div> <div> </div> <div> </div> <div> </div> <div>__________________________</div> <div> </div> <div>Marc Chamberland, MSc</div> PhD candidate Department of Physics Carleton University Ottawa (ON)</div> </div> <div> <div>On 2013-06-28, at 9:40 AM, Marc Chamberland <<a href="mailto:MarcChamberland@cmail.carleton.ca">MarcChamberland@cmail.carleton.ca</a>></div> <div> wrote:</div> <blockquote type="cite">Hi Leo, I'm replying to the mailing list because I think this might be relevant to other people. Your macro commands looked fine, so my first thought was there must be a problem with the visualization. After a bit of snooping in the source code, I tracked down the source visualization to a call to: void G4SPSPosDistribution::GeneratePointsInVolume() { G4ThreeVector RandPos; G4double tempx, tempy, tempz; G4double x, y, z; x = y = z = 0.; if(SourcePosType != "Volume" && verbosityLevel >= 1) G4cout << "Error SourcePosType not Volume" << G4endl; //Private method to create points in a volume [Marc's note: I'm skipping some irrelevant lines here] else if(Shape == "Cylinder") { x = Radius*2.; y = Radius*2.; while(((x*x)+(y*y)) > (Radius*Radius)) { x = posRndm->GenRandX(); y = posRndm->GenRandY(); z = posRndm->GenRandZ(); x = (x*2.*Radius) - Radius; y = (y*2.*Radius) - Radius; z = (z*2.*halfz) - halfz; } } (This is from the file G4SPSPosDistribution.cc within Geant4's source code.) As you can see, the visualization of a cylindrical (or annulus) volume does NOT take into account the inner radius (radius0); it only takes into account the outer radius! This is why the source looks wrong. I would consider this a bug in Geant4. It should not be too hard to fix by yourself, though. Cheers, Marc __________________________ Marc Chamberland, MSc PhD candidate Department of Physics Carleton University Ottawa (ON) On 2013-06-28, at 9:23 AM, Leo Read <<a href="mailto:leoread@gmail.com">leoread@gmail.com</a>> wrote: <blockquote type="cite">Hi Marc, Thank you for your prompt reply. The reason I posted is because I tried to write the code (see below the figure) to define my annular phantom but got the following result. I must be missing something very trivial as I can't seem to figure out how to get the source (white dots) to stay occupy the same volume as the phantom. I'd greatly appreciate any advice. I will post the final solution to the forum once I have it sorted out. Thanks, Leo ##code to define annular phantom /gate/world/daughters/name myphantom /gate/world/daughters/insert cylinder /gate/myphantom/setMaterial Water /gate/myphantom/geometry/setRmax 32 cm /gate/myphantom/geometry/setRmin 30 cm /gate/myphantom/geometry/setHeight 15 cm /gate/myphantom/vis/forceSolid /gate/myphantom/vis/setColor magenta /gate/myphantom/vis/setVisible 1 /gate/myphantom/attachPhantomSD ##code to define source to occupy region defined by the phantom /gate/source/addSource mysource /gate/source/mysource/setActivity 100000. becquerel /gate/source/mysource/gps/particle gamma /gate/source/mysource/setType backtoback /gate/source/mysource/gps/energytype Mono /gate/source/mysource/gps/monoenergy 511 keV /gate/source/mysource/gps/angtype iso #/gate/source/mysource/gps/mintheta 90 deg #/gate/source/mysource/gps/maxtheta 90 deg #/gate/source/mysource/gps/minphi 0 deg #/gate/source/mysource/gps/maxphi 360 deg /gate/source/mysource/gps/type Volume /gate/source/mysource/gps/shape Cylinder /gate/source/mysource/gps/radius0 30 cm /gate/source/mysource/gps/radius 32 cm /gate/source/mysource/gps/halfz 7.5 cm /gate/source/mysource/gps/centre 0.0 0.0 0. mm /gate/source/list /gate/source/mysource/visualize 2000 white On Fri, Jun 28, 2013 at 8:07 AM, Marc Chamberland <<a href="mailto:MarcChamberland@cmail.carleton.ca">MarcChamberland@cmail.carleton.ca</a>> wrote: Hi Leo, I'm not sure what you mean. Gate can create a cylindrical annulus: a cylinder with a different inner and outer radius. This can be used for either a phantom or a source. For example, if you want your source to be inside the phantom, you just have to define your source to be exactly the same shape as the phantom. Am I missing something? Marc __________________________ Marc Chamberland, MSc PhD candidate Department of Physics Carleton University Ottawa (ON) On 2013-06-28, at 7:56 AM, Leo Read <<a href="mailto:leoread@gmail.com">leoread@gmail.com</a>> wrote: <blockquote type="cite">Hello all, I'm new to Gate (using version 6.2) and it seems like there isn't a simple solution to model the commonly used annulus cylindrical phantom with the source embedded inside. Could somebody please help? Thank you all for your time and assistance. Best regards, Leo _______________________________________________ Gate-users mailing list <a href="mailto:Gate-users@lists.opengatecollaboration.org">Gate-users@lists.opengatecollaboration.org</a> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users </blockquote> _______________________________________________ Gate-users mailing list <a href="mailto:Gate-users@lists.opengatecollaboration.org">Gate-users@lists.opengatecollaboration.org</a> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users </blockquote> _______________________________________________ Gate-users mailing list <a href="mailto:Gate-users@lists.opengatecollaboration.org">Gate-users@lists.opengatecollaboration.org</a> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users </blockquote> </div> </div> </div> </body> </html>