Date: Mon, 20 Jan 2014 08:16:33 +0000
Dear all,
a recent comparison regarding the production of residual nuclei by low energetic neutrons on natural Carbon revealed curiously low values of C-14 by FLUKA. In order to understand this better we tried to print the neutron cross-section information (LOW-NEUT WHAT(4) = 4.0) but this did not prove to be helpful as the output is undocumented, which makes the correct interpretation impossible, and a posting to the discussion list did not yield any useful info either.
We're afraid that the obvious assumption that the printed values, which are labeled "prob", denote production probability is somewhat questionable because the values per group sometimes sum up to >1.0. Also the fact that for example the production of C-13 and C-14 in group 58 both show a prob. of 1.0 remains somewhat mysterious to us as we assume that they both originate from (n,g) reactions on C-12 and C-13 respectively. Any comments on the correctness of these assumptions and an explanation of the print-out are highly appreciated.
Analysis of X-section data which is publicly available in the IAEA's neutron gamma capture atlas or JEFF hint at the possibility that the (n,g) capture reaction of C-13(n,g)C-14 used by FLUKA could be considerably different and misses the significant peak around 0.1 MeV. Therefore, we wanted to ask if one of the developers could kindly confirm that the X-section used by FLUKA is similar to the IAEA data (see attachment) and that it includes the peak at 0.1 MeV.
Thanks a lot for your help
Chris & Helmut
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Chris Theis
CERN/DGS-RP - European Organization for Nuclear Research
1211 Geneva 23, Switzerland
Phone: +41 22 767 8069 Office: 892-2A-015
e-mail: Christian.Theis_at_cern.ch<mailto:Christian.Theis_at_cern.ch> www: http://www.cern.ch/theis
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(image/png attachment: C13-n_gamma_xsec.PNG)