About using mgdraw.f to calculate pka

Scoring
1

Dear FLUKA experts,

I am currently using the mgdraw.f file to calculate pka. After normal compilation and operation, I found that no data was stored in the file I specified. What could be the reason? Additionally, the neutron energy spectrum file I used has an energy level below 20MeV. Would this affect my results?

Thanks a lot in advance

Best regards

Yingming
mgdraw_empty .f (10.3 KB)
pka.flair (4.7 KB)

3

Dear FLUKA experts,

Please accept my sincere apologies for not previously explaining the meaning of PKA. PKA stands for Primary Knock-on Atom, which is a term used to describe the initial atom that is displaced from its lattice site due to the impact of an energetic particle, such as a neutron or ion, during irradiation. This displacement can initiate a cascade of events leading to structural damage within the material.

If my previous message caused any confusion, I apologize. I am deeply grateful for your understanding and assistance.

Best regards,

Yingming

4

Hallo,

the meaning of PKA was clear.
The problem is that your lines of code are written in the wrong place and they are never invoked (since they follow a RETURN statement), they should be placed before the last RETURN at the end of the mgdraw_empty.f file, in the USDRAW entry, Also, since you are interested in the PKA, you should search for it in the resnuc.inc and fheavy.inc stacks, and not in genstk.inc where light particles sit. Concerning the PKA possibly generated by a low-energy (<20 MeV) neutron, it can be found in fheavy.inc too.

5

Dear Francesco，

Thank you very much for your response. I have revised my code based on your suggestions. However, I still cannot find the “pka_count.txt” file in the designated folder. Could you help me understand what might be causing this issue? I truly appreciate your assistance.

code
code1196×512 110 KB

Best regards,

Yingming

6

Dear Yingming,

I have noticed multiple mistakes in your code

  1. The default energy unit in Fluka is GeV and not MeV.
  2. Output filename won’t be digested as expected.
  3. Better to call it like this and only once for all primaries and secondaries

CALL OAUXFI(‘PKA_COUNT.dat’,99,‘NEW’,IERR)

In your case file is opened for every interaction and closed number_interactions*bins times.
4. Also with your mgdraw subroutine it will be a fresh output of bins and counts for every new USDRAW entry - > always 1 count in a single bin.
5. File also might be not created without high statistics, because you are shooting high energy neutrons into a thin foil. Adding LAM-BIAS card with a small factor for hadronic inelastic interaction length may help to see such events at lower statistics.

Please check an mgdraw example from the Advanced course for better understanding:

Also, it’s much easier to perform binning as a post-processing step and not in the subroutine, so simply write a column of energies of each secondary.

Best regards,
Volodymyr