-- > Date: Thu, 20 Feb 2014 15:24:17 +0100 > From: fasso_at_mail.cern.ch > To: fluka-discuss_at_fluka.org > CC: jderrien_at_ulb.ac.be; dr.vittorio.boccone_at_ieee.org > Subject: RE: [fluka-discuss]: Neutron cross section > > Hi Jonathan, > > reading your first email, I wasn't sure where you had found PNP and PNA. > Now that you say you refer to the cross sections printed by LOW-NEUT, I > can assure you that neither is there with such names. The only ones that > more or less look similar are the following (I am quoting from the Manual, > Chapter 9): > > PNUP = upscatter probability (can be different from zero only if > there are several thermal groups) > PNABS = probability of Non-ABSorption (= scattering). > It is = SIGST/SIGT, and can sometimes be > 1 because of > (n,xn) reactions > PNEL, PXN, PFISS, PNGAM = partial cross sections, expressed as > probabilities (i.e. ratios to SIGT). In the order: > non-elastic, (n,xn), fission, (n,gamma) > > Group cross sections are mainly for neutron transport, not for activation. > The only exceptions are PNGAM and the 14-N(n,p)14-C cross section. The > situation is different for the few cases where pointwise cross sections > can be used (6-Li and 10-B(n,alpha)7-Li). In FLUKA, activation by > low-energy neutrons is obtained by a separate table of residual > nuclei, where the values are group dependent and uncorrelated with the > actual sampled reaction. > > Alberto > > On Thu, 20 Feb 2014, Jonathan Derrien wrote: > > > Hello Vittorio, > > > > Thank you to trying to answer my question. Well, for neutron with energies > > below 20 MeV, cross-section libraries are used. These cross-sections can be > > seen by using the command LOW-NEUT. Have you any idea about how compute the > > activation cross-section thanks to the data given by LOW-NEUT? > > > > Best, > > > > Jonathan > > -- > > [mywebsite.ulb.ac.be&x=46&y=10&] > > > > ____________________________________________________________________________ > > Date: Thu, 20 Feb 2014 14:26:53 +0100 > > Subject: Re: [fluka-discuss]: Neutron cross section > > From: dr.vittorio.boccone_at_ieee.org > > To: jderrien_at_ulb.ac.be > > CC: fluka-discuss_at_fluka.org > > > > Dear Jonathan, > > What do you exactly mean with "data used by Fluka, I'm not sure if I'm > > mislead by the name but I had some memories that those could be the > > probabilities of emission of a neutron and a proton (Pnp) and the one for > > the emission of a neutron and an alpha (Pna). > > > > best, > > V. > > > > > > On Thu, Feb 13, 2014 at 10:55 AM, Jonathan Derrien <jderrien_at_ulb.ac.be> > > wrote: > > Hello dear Fluka Users, > > I'm using the data used by Fluka for the low neutron and I found > > among the cross section and different probabilities two probabilities: > > PNP and PNA. I do not see what it is, so what is their meaning? > > Moreover, does anyone know how from these data to determine the > > activation cross section? > > Sincerely, > > > > Jonathan Derrien > > > > -- > > [mywebsite.ulb.ac.be&x=46&y=10&] > > > > > > > >Received on Thu Feb 20 2014 - 18:44:14 CET
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