Editing of physics list

I am working on the simulation of electron energy loss spectroscopy (EELS). I have data from a 200 keV transmission electron microscope (TEM) and I would like to fit the EELS spectrum with the simulation.

I already tried most of the Low Energy physics list. The most promising is the Penelope physics list and MicroElectronic Physics list (only for Silicon). Unfortunately, the simulated EELS spectrum has a plasmon peak shifted into the lower energies if compared with experimental data (please see attached figure).

In the attached figure, I compared simulated and measured data. For the simulation, I used Penelope physics list and G4GeneralParticleSource with Gaussian distribution of the primary beam (The primary energy was 200 keV and the deviation was 0.7 eV). The sample was 50 nm of Si3N4 with 15 nm of Mo. For the experiment, we used the same sample and the TEM microscope with the same primary beam parameters.

I would like to ask if I can edit (tune-up) the Penelope physics list to get a simulation that would fit better with the experimental data.

Thank you very much for your time.


I would suspect that edition of Physics List would not help. The problem is in physics models. Physics List is responsible for process/model configuration only. Physics is implemented in model classes. Do you tried to change cut in range? Can you explain the first and the second peaks in your plot?


Hello Vladimir,

Thank you very much for your answer. I tried to change the cut in range as well as the energy range. Is it possible to edit the physics model?

My plot is a low-loss region (loss < 100 eV) of electron energy loss spectroscopy. The first peak at zero energy loss is corresponding with electrons transmitted through the thin sample without any interaction or with an elastic interaction. The second peak, around energy loss of 20 eV, is corresponding with an inelastic interaction of electrons with the sample (mostly plasmon oscillations).

Thank you,