Hi Ben,
I have done the random seeded modification (see below) so it shouldn’t be using the same seed.
Also, reading through some previous issues I notice that this: Segmentation fault when using low energy and electric field seems to be a similar issue if cghw02 is using the field02 example which he alludes to in another thread.
T
//choose the Random engine
CLHEP::HepRandom::setTheEngine(new CLHEP::RanecuEngine);
//set random seed with clock time
G4long seed = time(NULL);
CLHEP::HepRandom::setTheSeed(seed);