I have simulated a scintillation detector, however it won’t record many events before I get a segmentation fault (core dumped). I use the GEANT4 Virtual Machine. Do I simply not have enough memory to generate and and transport the large number of scintillation photons?
I would suggest looking into the GDB debugger as it is helpful in finding the cause of segfaults.
Simulating optical photons is CPU intensive and you can scale down the scintillation yield to test if it related to this due to running in a virtual machine. Also, if you have memory limitations check how much data you are storing in hits etc. and whether it is all needed as this can fill up the memory.