Dear FLUKA experts：
I am bombarding a tungsten target with a 40MeV electron in fluka and I want to know the activation of the surrounding materials, after modeling and calculating I get the activation of the tungsten target, but there is no activation when I look at the surrounding distribution of water, iron, and aluminum. I would like to ask experienced experts whether this phenomenon is normal or not, and if there is an error, how do I need to modify my input card?
Here are my .inp and .flair input files：
40mv.flair (3.7 KB)
40mv.inp (2.7 KB)
Hello Zhao,
In principle, your input card does not contain any obvious mistakes. However, the simulation process is likely to require considerable CPU time before yielding meaningful results.
You are directing an electron pencil beam onto a target. In your setup, activation is primarily driven by photonuclear interactions occurring within the target. A fraction of the resulting neutrons must then escape the target and reach the region of interest in your geometry, which is oriented orthogonally to the beam axis.
If your main interest is neutron-induced activation, I would suggest the following optimizations:
- Increase the number of primaries to get a better statistics.
- Increase the EMFCUTs to reduce computation time spent on low-energy electrons and photons. Only photons in the giant dipole resonance region are likely to contribute meaningfully to neutron production.
- Apply more aggressive biasing to the photon inelastic interaction lengths to enhance statistical efficiency.
Let me know if you manage to fix the issue this way!
Cheers,
Daniele