Energy of particles in the frontier of two volumes

Hello everyone,

I am building an application in which I have a World volume filled with water and a BGO scintillation crystal in the very center of the World. From the center of the World (and thus the center of the BGO) I launch 4.4 MeV gamma-rays which will produce big amount of scintillation light and then Cherenkov light once it reaches the water.

I have my analysis set to record all the information about primary and secondary particles in the BGO and the World volumes, but there is one thing I find very interesting but do not know how to achieve: I would like to know the energy of the gamma when it passes from the BGO to the World, its energy just after the BGO frontier.

I would be very grateful if someone could help me do this.

Thanks in advance, Diego

You can do it from different ways. What comes to my mind at the moment is that you can set the BGO as a sensitive detector (which means that every particle that enters in this volume will be tracked step by step) and only get the particle energy when the fGeomBoundary status is true for the PostStep. The same can be done in a steppingAction class.