Questioins on physics list

What I am trying to simulate

The damage (total energy deposition) from electrons with energy ranges from 1 MeV - 5 MeV on a range of materials (including silicon and other Semiconductors).

Energy Depostion

For a while, I have been using the MicroElec physics list. But recently, I have encountered a bug, which led me to investigate the MicroElec package further, upon reading the work by Valentin et al., under the section Comparison with data from the literature for various parameters driven from ELF where they stated that;

The model presented in this paper thus considered valid up to 50 keV.

This has brought some doubt to me about my choice of the physics list. Now, clueless about what physics list to use. I considered just going back to the standard EM physics process that comes with Geant4, or someone here could offer me some more insights on which physics process I should choose.


I suggest to report either to Sebastien Incerti ( about this bug or to submit it to bugzilla. Unfortunately I can’t comment much on these models. However,
If you would like to use other physics models, I suggest to use either G4EMStandardPhysics_option4 or G4EMLivermorePhysicsList. In the last case you can push the cut down to 10 eV.

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The lower limit is not much of my concern; it is more about the performance of the package around 1 MeV. Also, I am not 100% sure if that is a bug that is in the package or something is wrong with my code which I am yet to investigate further.


based on your answer, I would choose G4EmStandardPhysics_option4. It has been developed specifically for low energy applications. Please look here: Report on G4-Med, a Geant4 benchmarking system for medical physics applications developed by the Geant4 Medical Simulation Benchmarking Group - PubMed

In regards to the MuElec models, Christophe Inguimbert of Onera, France, is taking care of these models. He comments the following:
"At these energy level (> MeV) MicroElec is not the model best suited because it will be very time consuming when modelling all secondary electrons. In that sense, the last release of microelec limits the e-/e- interaction cross section to a maximum energy of 10 keV.
Above the continuous models available in GEANT4 have to be preferred.
Most of time the accuracy of the calculation does not require to model all the secondaries. In a micrometric volumes only high energy secondaries with energies > keV are necessary. Indeed, the lower energy electrons produced in the volume will remain in this volume, and will deposit all their energy in this volume. With decreasing volume size, the cutoff energy of the secondary should in principle be reduced to keep a good accuracy. But the cutoff energy needs to be set lower than ~1 keV only for volumes at the nanometric scale (typicaly volumes < 5 nm).

Some comparisons between different models could be found in the following ref :

C. Inguimbert, P. Caron, Q.Gibaru, A. Sicard, N. Balcon, R. Ecoffet

“Surface ionizing dose for space application estimated with low energy spectra going down to some hundreds of eV”

IEEE Trans. Nucl. Sci. 68, no. 8, (2021), 1754–1763.


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This is definitely very helpful! Thank you so much, I will try out the other physics model!

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