Dear Expertise,
I am trying to simulate radiation from a neutron source of 252Cf.
Then, I noticed Flair’s HI-PROPE card has a limit of A<247. Then I set a user routine for the source and set for the atomic, mass, and isomer number as in my .f file attached. However, it is complaining about the HI-PROPE card still. Could you please guide me on how to solve the problem?
source_252Cf.f (19.0 KB)
(upload://apntO7uBbOqBYJVvYHW8pPJzQLl.flair) (3.8 KB)
Best Regards,
Melike
Dear Melike,
Unfortunately your flair file was not correctly uploaded so I cannot run your project for the moment. You can try to upload it once more, but the behaviour you describe is expected.
In fact, I would suggest a completely different approach, already outlined in this older thread. Basically, instead of defining a 252Cf source, you should load the appropriate neutron or fission fragment (FF) disributions from 252Cf fission via source routine. This would completely circumvent the A<247 limit.
I do not know whether you wish to simulate only the fission neutrons, the FFs or both; there are plenty of experimental data to use either way. In the past I have personally also used the GEF code to generate realistic FF distributions to load in FLUKA via source routine, but they may not be relevant for your problem.
source_newgen.f has plenty of options for sampling the particle energy, including from arbitrary user-provided distributions, so setting up a neutron spectrum representative of 252Cf fission neutrons will not be difficult. Have a look at section 3.4.4 of the routine (Sampling from histogram), where a simple external file can be provided with the neutron energy distribution.
Try it out and let us know if there are still problems.
Best regards,
Andrea
Hi Andrea,
Thank you for your explanation. I’ve set particle code for -2, which is for the heavy isotope ions in the source_newgen.f file. I’ve also set the atomic number, mass, and isomer number for the 252Cf in the source file. It compiles okay but finishes with error code = 137.
What could be the reason? I’ve attached my .inp file with my source file. Could you please take a look at them and provide me your guidance?
Best Regards,
Melike
Cf_252_test.inp (3.9 KB)
source_252Cf.f (19.0 KB)
Quoting @atsingan :
instead of defining a 252Cf source, you should load the appropriate neutron or fission fragment (FF) distributions
setting up a neutron spectrum representative of 252Cf fission neutrons will not be difficult. Have a look at section 3.4.4 of the routine (Sampling from histogram), where a simple external file can be provided with the neutron energy distribution.
Dear Melike,
I see from your input that you are interested in dose equivalent outside the Cf source shielding. Since you have at least several cm of Pb in all directions, the most likely source of dose will be the neutrons. The alphas and fission fragments will be quickly stopped after emission and will not contribute to the dose outside.
Some doubt could remain about photons; γ-rays from the Cf α-decay have low emission probabilities and energies up to just above 200 keV, so they should be well shielded. Perhaps some higher energy gammas from certain fragments could escape?
In any case, given the present impossibility of setting a Cf-252 ISOTOPE source, the best approach is to generate an appropriate neutron spectrum via source routine, as indicated in my previous reply. They (and the secondary radiation they will generate in the shielding) should account for the bulk of the dose.
Best regards,
Andrea
Thanks, Andrea,
It worked when I set a neutron source instead of isotope using the source routine.
Melike