Re: HEAVYION production

From: Paola Sala <paola.sala_at_mi.infn.it>
Date: Tue, 7 Apr 2009 12:38:55 +0200 (CEST)

Dear Francesca,
I had a look, that does not mean I checked everything. You should verify
by yourself that you get the correct distribution, either by writing the
sampled values on files, or by using fluka estimators. Also the physics,
how to model the fragment distributions, is up to you!
The overall structure seems ok.
Put a SAVE statement for the arrays you wish to keep (for instance TEGR),
it's safer.
When you sample, both the energy of the neutron and the fragment mass, I
think that the indices are wrong: instead of using I and (I+1) you should
put (I-1) and I. Otherwise you'll never get the first bin, and you could
get I+1>limit.
When sampling from a gaussian, set a protection against negative
energy/mass values (from long tails)
You say that you sample only the forward direction: where is it done?

Energy is correctly in GeV, (not in GeV/nucleon)

Ciao
Paola
> Dear FLUKA users,
> I made a simulation in order to score FFs energy deposition in a gas.
> The fragments are emitted isotropically in angle and their emission point
> is "homogeneously sampled"
> inside the target.
> The target is a cylinder of U3O8 (radius = 4cm). FFs are sampled only
> in the forward direction, since
> a backing (not simulated) would stop FFs emitted backwards.
> FFs atomic masses and atomic numbers are generated according to a
> distribution.
> In order to take into account energy conservation, FFs total available
> kinetic energy is given as the
> sum of the V+0.8*Tn,where
> V is given by the formula:
> 0.1178 Z**2 /(A**(1/3)) + 5.6 MeV
> and Tn is sampled from an experimental spectrum.
> The total kinetic energy is then distributed between 2 fragments in
> inverse proportion to the fragment
> mass:
> El/Eh = Mh/Ml
>
> with:
> El= kinetic energy of the light fragment
> Eh= kinetic energy of the heavy frgment
> Mh = atomic mass of the heavy fragment
> Ml = atomic mass of the light fragment
> Since it's the first time I simulate FFs, I'm not so sure I made
> everything
> correctly. Could someone give a look,please?
> And could someone tell me if FFs energy is to be given in GeV or GeV per
> unit atomic mass,please?
>
> Thank you very much,
> best regards,
> Francesca Belloni

Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
Received on Tue Apr 07 2009 - 13:31:31 CEST

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