[fluka-discuss]: Neutrons on carbon still

From: <francesca.belloni_at_libero.it>
Date: Wed, 5 Aug 2015 16:22:04 +0200 (CEST)

Dear all,

       I am still trying to get alphas out of n+diamond_material interaction, but with no success.
So I switched to another code and for a 5 m thick diamond, I get alphas (and other heavy ions).
Then I went back to FLUKA and reduced the input at the minimum: only a diamond 500 cm thick and neutrons striking it.
I asked RESNUCLEI in the diamond region, but I only get C13 and C14, as product of n+natC.
Could anyone give a look, please?

If I look at the output file everything seems to have been activated
In my *.inp LOW-NEUT, WHAT(4)=4 asks for a printout of the information about the residual nuclei. This is dumped on the *.out file.

If I look at my *.out file I see that the neutrons I am shooting belong to the Neutron (low energy)
Xsec group number 5:

Neutron group n.: 5 upper limit 1.8221E-02 GeV, average energy 1.7995E-02 GeV,
                                  velocity 5.7846E+09 cm/s, momentum 1.8477E-01 GeV/c

Later on, on the same *.out file, there is written that the FLUKA medium number 26 corresponds to the Xsec medium number 1.

   Fluka medium Name Xsec medium atomic density Id. 1 Id. 2 Id. 3
     number number ( at/(cm barn) )

         1 BLCKHOLE 0 0.0000E+00 0 0 0

         2 VACUUM 1000 0.0000E+00 0 0 0

        26 DIAMOND 1 1.7649E-01 6 -2 296

Going down again in the *.out file there is written:

nuclei informations for medium 1
  Group: 1 A Z Prob
              12 6 7.54E-01
              11 5 9.09E-01
              13 6 9.09E-01
              12 5 9.36E-01
               9 4 1.00E+00
              14 6 1.00E+00
               1 1 7.44E-02
               2 1 1.07E-01
               4 2 6.44E-02

 Group: 5 A Z Prob
              12 6 7.87E-01
              11 5 9.11E-01
              13 6 9.12E-01
              12 5 9.48E-01
               9 4 1.00E+00
              14 6 1.00E+00
               1 1 4.18E-02
               2 1 1.18E-01
               4 2 5.25E-02

Therefore it means that in FLUKA the neutrons I am shooting have a certain probability (different from 0.0) to interact with the diamond and give alphas, Be-9, B-11 and B-12.
I thought it could have been a problem of statistics (I shoot 9E+7 neutrons on a material where lam-bias=-0.001) . But looking at those probabilities, it seems it's more likely to get B-12 than C-13 (IF i am understanding the table correctly...which is not sure).
But I get C-13 and C-14 only.

What am I missing,please?Thanks,regards,Francesca


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Received on Wed Aug 05 2015 - 17:54:48 CEST

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