Hi,
the parameterisation of the electric field used in the silicon example is specific to a depleted planar silicon sensor; I don’t think it is applicable to your case. If I understood correctly, you are trying to simulate a parallel-plate chamber filled with pure SF6. In this case, you don’t need to define the electric field via a ComponentUser object; you can simply use ComponentAnalyticField and set the active medium to be the MediumMagboltz object (gas) you set up at the beginning of your program.
You might also want to check the dimensions (in particular thickness and strip pitch). A gas gap of 100 μm seems a bit small considering that you operate at 0.1 bar.
I don’t know what your AvalancheNIMicroscopic class does so I cannot really comment on this part of the code, but an electron transport cut of 10-20 (eV?) seems odd to me.