Scoring (or counting) number of specific process

Dear FLUKA users,

Hi. I want to score the number of specific process: especially, the muon decay* with its spatial distribution.
What I’ve tried is scoring fluence distribution of ANEUTRIM (muon anti-neutrino) using USRBIN. But, the neutrinos are traveling, and it definitely makes fluence even there’s no decay in the bin. So I think folloing methods can be considered:

  1. Count the specific process its number and where it happen
  2. Stop transportation of neutrino for its first step of scoring bin
  3. Time gate after decay (like after >500 ns by considering muon mean life time of ~2200 ns)

Is there ways to execute the methods above, or suggestions of other ways are always welcome.


*A three body decay of muons. e.g., mu+ → POSITRON + ANEUTRIM + NEUTRIE

Dear @eng_jwbae,

Thank you for your question!

If you are looking to count the number of muon decays, then there is no ready-to-use scoring targeted at this and one would have to come up with work-arounds, as those that you mention. However, I recommend tailoring a user routine to your needs.

Please find here a routine mgdraw.f (14.6 KB) that will dump the information that you select. In particular, at the end of the file, there are the following lines:

      IF ( ICODE .EQ. 102 .AND. JTRACK .EQ. 10) THEN
      END IF

which filters on the interaction code ICODE for 102: particle decay secondaries and JTRACK for 10 (FLUKA particle id) for positive muons, and then saving the X, Y and Z coordinates. Of course, if you wish to filter also on more variables, e.g. region number MREG, or to save more information, e.g. direction cosines, this is also possible.

Please find here also a working example test.inp (1.1 KB) that shoots 0.1 MeV muons which decay within meters based on the output.dat (910 Bytes).

Please find here more information on how to use user routines. You will have to compile linking your customized user routine and add a USERDUMP card (as in the example I attached above) to activate the mgdraw.f routine.

As common practice for future questions, please upload your input file as well.

I hope this helps.

Best regards,
Daniel Prelipcean

1 Like

Dear @dprelipc,

Thank you very much of your answer. I’ve never used the user routine before and it is a perfect tutorial for me. Thank you for your support with kind example of the .f and input files.

With my best,