FLUKA: Group xsec

[Laurent APHECETCHE <aphecetc@in2p3.fr>]

Hi,

I'm trying to get group damage cross-sections out of ENDF-B/VI files,
using NJOY99.24, for the FLUKA neutron groups. The idea is then to
convolute them with neutron fluxes given by FLUKA to get DPAs.

In order to be consistent, and to be sure I'm using NJOY the correct
way, I first tried to get back something simple, e.g. the total
FLUKA-grouped xsec, which I can get using WHAT(4)>0 in the LOW-NEUT
card.

I've tried with Pb-208. Following the document :

E. Cuccoli, A. Ferrari, G.C. Panini
        A group library from JEF 1.1 for flux calculations in the LHC
        machine detectors
        JEF-DOC-340 (91) (1991)

I've seen that grouping is done using Legendre up to order 5, using
weighting function of vitamin-j.

First question : in the NJOY version I'm using, I've not found such a
weighting function (there's a vitamin-e, though). Did I miss it ?

Then, using e.g. vitamin-e, I get slightly different results from the
ouput of FLUKA. From the ENDF file, I'm using RECONR + BROADR(@293K) +
GROUPR Njoy modules. Is this the correct way of doing things ? Are the
differences I get only due to the different weighting function, or do I
miss something more important ?

Best regards,

-- 
Dr. Laurent APHECETCHE (mailto:aphecetc@in2p3.fr) (IN2P3-CNRS) 
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Collaborations PHENIX http://www.phenix.bnl.gov/~aphecetc et MEGAPIE.