Time-dependent material assignment during IRRPROFI irradiation

Geometry and Materials
1

Versions

FLUKA: 4-5.0
Flair: 3.4-1

Description

Hello FLUKA users,

I have a conceptual question regarding time-dependent materials during irradiation.

I would like to model a system where the geometry remains fixed, but the material assigned to one region changes periodically during the irradiation history. For example, a box/container that alternates between:

  • water-filled,

  • then air-filled,

  • then water-filled again,

during a given IRRPROFI-defined irradiation period.

My main interest is the activation/residual nuclei production in regions downstream of this volume.

I was wondering whether FLUKA provides any way to dynamically change the material assigned to a region during a run, mainly to avoid performing multiple separate irradiation runs for each phase of the cycle.

Thank you very much for your support and guidance.

2

Dear Carlos, this is conceptually impossible. Materials can only be changed when simulating the radionuclide decay stage, after the completion of the prompt radiation stage, where the original materials get activated. In fact, subsequent primary histories should not be seen as following each other along the physical time, so allowing for a geometry change meanwhile. They are actually meant to see the same geometry, in order to allow for the Monte Carlo calculation of the macroscopic quantities of interest. The change of the material in the box corresponds to a different geometry, which needs to be evaluated independently.

3

Dear Francesco Cerutti, thank you again for the helpful explanation.