RE: [fluka-discuss]: Re: Question about W neutron resonces

From: Matteo Magistris <>
Date: Thu, 21 Mar 2019 15:47:48 +0000

Dear Vladimir,

Thank you for your query. I have checked your input, and unless I am mistaken in WHAT6 of the LOW-MAT cards you assign the same "tungsten" low-E neutron cross-sections to both your W182 and W183 materials, which may defeat the purpose of using a compound material for tungsten.

The problem is, there are no isotope-specific cross-sections in the list of FLUKA materials (see manual for tungsten, but only for tungsten at different temperatures. This means that in terms of interactions with low-E neutrons you can only work with natural tungsten.

Alternatively, you could use Fluka to simulate the neutron spectra and then do an off-line folding of these spectra with external cross-sections of low-E neutrons for different isotopes, which you can find in a nuclear database. However, in this case you should be aware of the fact that the spectra provided by Fluka will be affected by the cross-sections which are already implemented in Fluka.


-----Original Message-----
From: <> On Behalf Of babintsev
Sent: 20 March 2019 10:47
To: fluka-discuss <>
Subject: [fluka-discuss]: Re: Question about W neutron resonces

   Hi, ALL,

  I have checked  different variants (and manuals also) about
   neutron resonances, They absent in  the output for
   TUNGSTEN (W), And as I can see - for all other materials also.

   May be somebody knows answers for the following questions :

   1) I tryed to compose material from 182_W and 183_W isotopes,
      but I think, that something is wrong...
      Could you please check my test.inp - file in the atachment ?

   2) does anybody know the simple method to simulate some
      known resonances for the given material ?
      (where are there data with cross-section vs E ?)

   3)  is there open and free method to fit (reconstruct)
      this simulated or real resonances ?


  Vladimir Babintsev

16.03.2019 8:57, babintsev пишет:
>  Dear experts,
>  I want to check neutron resonances like ex-5 with Cd foil.
>  For this I use lead target in moderator (polyethylene)
>  then I look at  N flux using the hole in the concrete wall.
>  I use W foil  and NEW-DEFA
>  In the attachment there is the picture of N flux into
>  W-foil and output from the foil.
>  There is NO ANY resonance here.
>  So, my questions :
>  - I use TUNGSTEN here, it is known that natural W consists from
>    4-5 stable isotopes, which have neutron resonancies
>    TUNGSTEN in FLUKA is natural ? 4 isotopes ?
>  - if TUNGSTEN is not natural - then how I can create this material ?
>    I cannot find any example, how to compose materials from isotopes -
>    because I need names , which I do not know
>    could you please give me this example ?
>  - what else I must do to see the picture as I see for Cd in ex-5
>    with neutron resonance ?
>  thank you
>  Vladimir Babintsev

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