MAT-PROP for low-pressure gases

Dear Fluka experts,

I’m trying to model a Geiger counter filled with low pressure argon (approximately 0.1 atm). As far as I understood from the user manual, in order to do so I have to use MAT-PROP card with SDUM=blank. I have several questions regarding this card:

  1. What are the limitations for pressure lower limit? Is it possible to set it as low as I want (like 0.01 atm)?
  2. How does ‘mean ionization potential’ work? I understand that an atom has electron shells with various binding energies. When there is an interaction with the atom, does the program account for atom shells with various binding energies or it assumes that the atom has only one ‘average’ shell with ‘mean ionization potential’?
  3. How is mean ionization potential related to the gas pressure for this card?

Thank you in advance,
Alexy

Hello Alexy,

thank you for your question. I am looking into it, and will let you know as soon as possible. In the meantime, if the simulation is urgent, I would suggest defining a material for your geiger counter which already has the correct density at that pressure.

Thank you,

Stefano