From: Alberto Fasso' (fasso@SLAC.Stanford.EDU)
Date: Fri Jun 20 2003 - 19:52:16 CEST
You have posted these questions already, but I have not answered before
because I don't know the answer to all of them. But since nobody
else has reacted, I will at least give you the easy ones.
On Fri, 20 Jun 2003, Bernhard Schwingenheuer wrote:
> Dear FLUKA community,
> I am using FLUKA for neutron scattering (9.5 MeV) in nitrogen N14.
> In USDRAW I try to learn s.th. about the implemented scattering
> processes for ICODE=300.
> A few questions come up when I look at the information I get:
> 1) Is the information stored in the common block RESNUC meaningful at
> the entry USDRAW with ICODE=300 ?
Yes. (If you look in the manual at the list of isotopes present in the FLUKA
neutron library, for 14N there is a "Y"(es) in the "RN" (Residual Nuclei)
> 2) for those reactions when NP=2 and the 2 secondaries are neutron +
> gamma I find that the sum of outgoing energies is typically 2 MeV larger
> than the neutron energy before the scattering. If these are inelastic
> reactions then I expect to have N14 before and after the scattering and
> hence energy should be conserved (averaged over many reactions).
I don't know this one. Maybe I should do some tests.
> 3) For thermal neutrons I see some cases with NP=2 and the secondaries
> are neutron + proton!!
> The proton energy is always 0.58 MeV (= 13/14 of the Q value of (n,p)
> reaction for N14). Typically there are several of these reactions for a
> given beam particle! One neutron makes several (n,p) reactions???
I don't know about NP=2 and secondaries = neutron + proton (or maybe is
there hydrogen in addition to nitrogen?).
Concerning one neutron making several (n,p) reactions, it is possible, if
you have non-analog absorption set up for the thermal
group. See more information in the description of option LOW-BIAS.
If you don't want this feature, issue a command LOW-BIAS with
WHAT(2) = 73. for the regions of interest.
> 4) what is the meaning of the RESNUCLEi output if I have only 1 beam
> particle, i.e. "START 1."?
It means "number of residual nuclei (of a given type) per incident
particle weight", whether you have only 1 beam particle or more.
If the beam particle has weight 1 (the most common case), then it means
"number of residual nuclei produced by that particle".
-- Alberto FassÚ SLAC-RP P.O. Box 4349, MS 48, Stanford CA 94309 email@example.com
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