Simulation of displacement events due to low energy e- beam

Physics Processes, Models and Cross Sections
1

Hi everyone!

I am looking to simulate the interaction of a material (diamond) with a relatively low-energy e- beam (200 keV). I am particularly interested in obtaining the distribution of target atom displacement events (vacancy production) as a function of depth in the material. Practically, this limits the useful range of interactions to about 200 → 140 keV or so, based on the mean displacement energy of atoms in diamond. I don’t need to track secondary ions since their kinetic energy is very unlikely to be high enough to cause subsequent damage.

I would be very grateful for any advice on which physics list / processes I might look at to simulate this behaviour please? I had been hoping to use the extensions in the microelectronics lists, but unfortunately there all elastic collisions are modelled simply as a trajectory change, rather than elastic energy transfer to the target.

Thank you for your help!

2

Hi, I suppose you would like to calculate the displacement damage? maybe you can look at Test 58. I found these slides online. https://indico.cern.ch/event/398318/contributions/949428/attachments/1184736/1716940/Tacconi_Geant4.pdf
probably they are helpful for your case.

3

Dear guatelli,

Thank you for your reply. Unfortunately, this example and associated NIEL code doesn’t seem to have been updated since v10.4 - I assume that the patches provided won’t translate directly to v11+ without modification, which is beyond the scope of this work. The current physics manual still refers to test58 but I can’t see any relevant copy.

Additionally, TestEm1 seems to contain a NIEL calculation but as far as I can tell it will only compute NIEL for ions, rather than electrons.

Thanks again for the help