In the scintillator, does the electron only have one scintillation process or several scintillation processes and gradually lose its energy？
The scintillation process only observes the energy loss of the electron, and creates the appropriate number of optical photons each step. The scintillation process itself does not modify the energy of the electron. Yes, this violates conservation of energy, but it should be a small effect.
So,a electron will create photons in each step.
Thanks for your help!