I think can work around the problem without too much trouble (at least, this has worked for me) by putting a shell of lead around the outside of whatever relevant other volumes I have used in my simulation -- then no positrons escape the world volume and I receive no vectors with ID = 4. But this seems like a "klugy" fix to me.... Thanks for your response. Jonathan <div>On 3/2/07, <a href="mailto:yuxuan.zhang@di.mdacc.tmc.edu">yuxuan.zhang@di.mdacc.tmc.edu</a> <<a href="mailto:yuxuan.zhang@di.mdacc.tmc.edu"> yuxuan.zhang@di.mdacc.tmc.edu</a>> wrote:<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Hi, I think this is quite common for the GATE simulation. I always have these kind of problem and no easy way to solve it. yuxuan <table width="100%"> <tbody><tr valign="top"> <td> </td><td>"Jon Engle" <<a href="mailto:engle.jonathan@gmail.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">engle.jonathan@gmail.com</a>> Sent by: <a href="mailto:gate-users-bounces@lists.healthgrid.org" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">gate-users-bounces@lists.healthgrid.org</a> 03/01/2007 09:01 PM </td><td>                To:        <a href="mailto:gate-users@lists.healthgrid.org" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">gate-users@lists.healthgrid.org</a>         cc:                 Subject:        [Gate-users] core dump</td></tr></tbody></table><div> All, For my work, I would like to be able to simulate positrons emitted from a point source in air. To do so, I am enclosing the source in a 1 mm radius sphere of water for attenuation and annihilation. I recognize that doing so likely means some positrons will escape the world volume without annihilating. However, sometimes (not all the time), my simulations of point sources at different locations return a segmentation violation and a core dump. Often, I am able to rerun the same simulation with a different seed without problems. The error message is below, slightly abbreviated to reduce the size of my log files (if it might help to have a more detailed output, I am happy to change my settings and provide this): . . . . [GateTrajectoryNavigator: :FindAnnihilationGammasTrackID]  WARNING : positron found and photonID vector size: 1 [GateTrajectoryNavigator::FindAnnihilationGammasTrackID]  WARNING : positron found and photonID vector size: 1 [GateTrajectoryNavigator::FindAnnihilationGammasTrackID]  WARNING : positron found and photonID vector size: 1 [GateTrajectoryNavigator::FindAnnihilationGammasTrackID]  WARNING : positron found and photonID vector size: 1 [GateTrajectoryNavigator::FindAnnihilationGammasTrackID]  WARNING : positron found and photonID vector size: 1 [GateTrajectoryNavigator::FindAnnihilationGammasTrackID]  WARNING : positron found and photonID vector size: 1 [GateTrajectoryNavigator::FindAnnihilationGammasTrackID]  WARNING : positron found and photonID vector size: 1 [GateTrajectoryNavigator::FindAnnihilationGammasTrackID]  WARNING : positron found and photonID vector size: 4 *** Break *** segmentation violation Generating stack trace... /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file /usr/bin/addr2line: 'gate': No such file 0x0000000000570630 in GateDigitizer::Digitize() + 0x1f0 from gate 0x000000000057fa6e in GateOutputMgr::RecordEndOfEvent(G4Event const*) + 0x8e from gate 0x0000000000575f7f in GateEventAction::EndOfEventAction(G4Event const*) + 0x8f from gate 0x0000000000a4c30a in G4EventManager::DoProcessing(G4Event*) + 0x6da from gate 0x000000000099e7e1 in G4RunManager::DoEventLoop(int, char const*, int) + 0xd1 from gate 0x000000000099d0c1 in G4RunManager::BeamOn(int, char const*, int) + 0x91 from gate 0x0000000000567edb in GateApplicationMgr::StartDAQ() + 0x11b from gate  0x00000000005b884b in GateApplicationMgrMessenger::SetNewValue(G4UIcommand*, G4String) + 0x12b from gate 0x0000000000bd3f18 in G4UIcommand::DoIt(G4String) + 0x388 from gate 0x0000000000bdd772 in G4UImanager::ApplyCommand(char const*) + 0x482 from gate 0x0000000000be560d in G4UIbatch::SessionStart() + 0x3fd from gate 0x0000000000bda705 in G4UImanager::ExecuteMacroFile(char const*) + 0x45 from gate 0x00000000005a5cb0 in GateUIcontrolMessenger::LaunchMacroFile(G4String) + 0xb0 from gate 0x00000000005a5e27 in GateUIcontrolMessenger::SetNewValue(G4UIcommand*, G4String) + 0xd7 from gate 0x0000000000bd3f18 in G4UIcommand::DoIt(G4String) + 0x388 from gate 0x0000000000bdd772 in G4UImanager::ApplyCommand(char const*) + 0x482 from gate 0x0000000000566671 in main + 0x751 from gate 0x000000381d01c784 in __libc_start_main + 0xf4 from /lib64/libc.so.6 0x00000000005653aa in TApplicationImp::ShowMembers(TMemberInspector&, char*) + 0x9a from gate dogaterun.positrons: line 3: 29484 Aborted                 (core dumped) gate main.ps.positrons.x0y0.mac thanks again, -- *************************************************************************** Jonathan Engle, Lab Tech Utah Center for Advanced Imaging Research 729 Arapeen Drive, Salt Lake City, UT 84108-1218 (801) 581.8288, <a href="http://englephysics.com/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">englephysics.com</a></div> *************************************************************************** <tt>_______________________________________________ Gate-users mailing list <a href="mailto:Gate-users@lists.healthgrid.org" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">Gate-users@lists.healthgrid.org</a> <a href="http://lists.healthgrid.org/mailman/listinfo/gate-users" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://lists.healthgrid.org/mailman/listinfo/gate-users</a> </tt> </blockquote></div> -- *************************************************************************** Jonathan Engle, Lab Tech Utah Center for Advanced Imaging Research 729 Arapeen Drive, Salt Lake City, UT 84108-1218 (801) 581.8288, <a href="http://englephysics.com">englephysics.com</a> ***************************************************************************