Dear Chenyen,
Of all possible combinations of:
- projectile;
- energy;
- target; and
- ejectile(s),
cross sections are either:
#1 measured already (data end up in EXFOR);
and/or
#2 predicted via models (TENDL being the most proliferative, but I think not
even TENDL authors tell users to belief the whole lot in blind faith).
In many cases #1 is simply not available due to various difficulties eg beams
which are not available in standard facilities, or energy-target combinations
which can be killers in funding proposals.
Evaluated libraries (ENDFB, JENDL, JEFF, ...) are the results of curation based
on both #1 and #2. Evaluators fill in the gaps by way of #2. O18, in particular,
is present in ROSFOND but not in the more widely known evaluated libraries.
FLUKA too, implements cross-sections to the best endeavour, based on #1 where
available, substantially complemented by models which are signature of FLUKA and
which FLUKA developers take pride in :)
The smart and normal way to know the kinds of reaction in FLUKA is to run the
simulations, explore and admire the beauty!
:) mary
On 04 January 2014 at 04:13 Chenyen Lee <chenyenlee_at_gmail.com> wrote:
> Dear Anton and Forum ：
>
> I would like ask about the cross section used in fluka.
>
> According to the manual that "Inelastic cross sections for hadron-hadron
> interactions are represented by
> parameterised fits based on available experimental data [PDG]."
> However,I do not know how to find the cross section library in Particle Data
> Group.
>
> Take O18 for example, it's a relative rare element.
> In ENDF, http://www.nndc.bnl.gov/sigma/ <http://www.nndc.bnl.gov/sigma/>
> I select all of the 8 library to find proton interaction with Oxygen.
> It seems that I can find some 18O(p,n)18F,but there is no 18O(p,x)15N out of
> it,
> not even 16O(p,a)13N which I think 16O is very common element.
>
> Before the advise from Anton, I do not even know there is non-negligible
> fraction of neutrons from other processes.
> TENDL-2011 Nuclear data library provides huge variety.
> ftp://ftp.nrg.eu/pub/www/talys/tendl2011/proton_html/O/ProtonO18xs.html
> <ftp://ftp.nrg.eu/pub/www/talys/tendl2011/proton_html/O/ProtonO18xs.html>
>
> I can score the products like F18,O18,N14 , but is there a smart or normal
> way
> to know what kinds of reaction actually occurs in fluka ?
>
> Thanks in advance
>
>
> Lee
>
>
>
>
> 2013/11/30 Anton Lechner <Anton.Lechner_at_cern.ch
> <mailto:Anton.Lechner_at_cern.ch> >
> > >
> > From the link you included in your file, I guess that you are only
> > interested in neutrons produced in following reaction:
> > p + O18 -> F18 + n
> >
> > If this is the case, you should not forget that a non-negligible fraction
> > of neutrons also emerge from other processes, e.g.:
> > p + O18 -> O17 + n + p
> > p + O18 -> N14 + n + alpha
> >
> > USRYIELD will count all neutrons, also those from the latter
> > interactions.
> >
> > If you are only interested in the first reaction, you could for example
> > use USDRAW in the MGDRAW user routine. By including
> > '(RESNUC)', you have access to the atomic and mass number of the residual
> > nucleus and you can filter neutrons accordingly. I included some sample code
> > below.
> >
> > Cheers, Anton
> >
> >
> > * Check that incoming particle is a proton and that interaction is
> > inelastic:
> > IF ( JTRACK .EQ. 1 .AND. ICODE .EQ. 101 ) THEN
> >
> > * Check that residual nucleus is F18:
> > IF( ICRES .EQ.9 .AND. IBRES .EQ.18 ) THEN
> >
> > * Loop over all secondaries
> > DO 99 INMB = 1, NP
> >
> > * Check that secondary particle is a neutron
> > IF ( KPART( INMB ) .EQ. 8 ) THEN
> > * Here you might want to write to a file e.g. the neutron energy TKI
> > (INMB ) or simply count neutrons
> > ENDIF
> >
> > 99 CONTINUE
> >
> > ENDIF
> > ENDIF
> > >
Received on Thu Jan 09 2014 - 20:20:11 CET