Re: [fluka-discuss]: Problem(?) with secondary protons and neutrons after alpha interaction with aluminum

From: Ivan <>
Date: Sat, 22 Dec 2018 21:34:11 +0300

Dear Mikhail,

Thank you for your kind response! I fixed the source routine and also it
was a problem with compiling and linking of routine, because I always
followed instructions on the official website:

> * 2) compile the modified routines (with the fff script on LINUX/UNIX):
> fff yyy.f (produces a new file yyy.o)
> * 3) link them (with the lfluka script on LINUX/UNIX) to the FLUKA
> library and any additional library of interest (for instanceCERN
> <>LIB):
> lfluka -o myfluka -m fluka yyy.o

Not paying attention to the fact that, in my case, I should use
"ldpmqmd" instead of "lfluka". It was not clear for me. Thank you very
much for your help!

Best regards,
Ivan Gordeev

21.12.2018 18:59, Mikhail Polkovnikov <Михаил Полковников> пишет:
> Dear Ivan,
> There is an error in your source file! Total weight of your particle
> spectrum is unity, but you multiply the weight of the source particle
> by ENNUM value for some reason.
> The correct expression:
> Best regards,
> Mikhail
> On 18.12.2018 18:10, Ivan wrote:
>> Dear FLUKA experts!
>> I have a problem or misunderstanding in work. I have a geometry -
>> cylinder H = 12m, D = 6m, with air inside and aluminum shell 5.55 cm
>> thick (see attached input file). And from the sphere of 7m diameter
>> inside the sphere alpha particles emitted with fluence spectrum
>> (attached user source routine and spectrum) in case that inside will
>> be uniform and isotropic fluence of these particles with value
>> 1/(pi*R^2). So, in the output secondary proton spectrum inside
>> cylinder, I have a "fall" starting from about 100 MeV and up to about
>> 400 MeV and same picture for neutrons, I found this confusing,
>> because I have results for the same task from MCNPX and it is about
>> the same for alpha inside, but protons and neutrons spectra are
>> smooth and without these "falls". I just cant believe that physics
>> models can be so different and cause this "fall" in spectra and also,
>> I am also not sure about my source routine and I tried everything
>> with physics, it seems like I don't have a clue now. Also, before
>> this task I did the same, but emitting protons on the cylinder using
>> the same way and output fits with the results from MCNPX pretty well.
>> Please help! I am new using FLUKA and seems lack of ideas now...
>> Attached: input file, source routine, spectrum, output files (23 -
>> protons, 24 - neutrons, 27 - alpha), figures of "fall" for protons
>> and neutrons.
>> Thanks in advance!
>> Best regards,
>> Ivan Gordeev
>> P. S. Sending this for the third time, just don't know if it is sent
>> or not...

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Received on Sat Dec 22 2018 - 20:52:14 CET

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