Re: HEAVYION production

From: <>
Date: Tue, 7 Apr 2009 21:18:16 +0200 (CEST)

Dear Paola,
    thanks a lot for corrections and suggestions!
Yes,I had checked the FFs mass and energy distributions, and looked
correct. But I feared some "not strongly evident" mistake, and for example
I had not realized I had use indices I and (I+1) instead than (I-1) and I.
    As for sampling only in forward direction,excuse me: I had to speak
about scoring,not about sampling.
      I meant that FFs are emitted on 4pi, but the gas is situated only in
the forward direction with respect to the U3O8 target. Since I score
energy deposition only inside the gas, I'm scoring it in the forward

Thank you very much!

Best regards,
Francesca Belloni
> 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 Sun Apr 19 2009 - 19:43:29 CEST

This archive was generated by hypermail 2.2.0 : Sun Apr 19 2009 - 19:43:31 CEST