Optical Error Message about Boundary/Step Size


I’ve been facing the following error message as a result of my implemented scintillation for multiple photons. I’m not sure what the issue is here, so any help would be super appreciated!!

-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : OpBoun06
      issued by : G4OpBoundaryProcess
G4OpBoundaryProcess: Opticalphoton step length: 7.13e-09 mm.
This is larger than the threshold 1e-09 mm to set status StepTooSmall.
Boundary scattering may be incorrect.

*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------

It is safe to ignore this if it happens for a small fraction of boundary interactions. Occasionally the algorithm to determine the scattering doesn’t produce a good result. The photon continues to propagate.