tracking or geometry problem?

From: Chrysostomos Valderanis <>
Date: Mon, 23 Aug 2010 18:54:15 +0200


In the input file I attach, a proton is travelling through vacuum and
bends with magnetic fields. In the process of debugging it I wrote some
code to track the boundary crossings. You can find the log file also
attached. I have two questions for the mailing list:

1. Since only tracking is required in my code and no fluctuations exist
(ie pencil beam), I though that the boundary crossings of two events are
going to be *exactly* the same. As you can see from the logfile this is
not the case. What am I missing?

2.The proton is not crossing all the boundaries I was hoping to. As you
can see from the logfile there is a region succesion that is aborted at
line 265. the proton is exiting a region I was hoping to enter first.
The net result of this is that the proton is not seeing the full
magnetic length and gets a wrong direction. I checked with the geometry
and didn't find anything unusual. Is there anything else to check?

Thank you in advance,

Received on Tue Aug 24 2010 - 19:51:11 CEST

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