Hi! I have made a bulk ice simulation that produce Cherenkov photons and an active surface at the center records the photons’ direction and energy distribution. I want to use the output of this simulation as an input to another simulation of multiple detector models to understand their sensitivity. I looked into the application developer’s guide and it seemed I can only use a file as an input for energy distribution using General Particle Source, but I would like to use an input file for momentum directions too. Could you please point to any resource that gives some insight on how to deal with this?
The most straightforward method would be for you to write your own PrimaryGeneratorAction. Read your file, and use the information in it to create your own primary particles and attach them to primary vertices. Geant4 does not provide that functionality in a built-in way.