From: Alfredo Ferrari (alfredo.ferrari@cern.ch)
Date: Tue Apr 22 2003 - 23:43:12 CEST
Hi
I believe I already answered about the TARC data. DON'T LOOK at ref. [2]
but RATHER LOOK AT THE OFFICIAL TARC REFERENCES, where you can find the
Fluka results for the TARC experiment. If you get numbers in agreement
with those ones ok, if not you have some mistake somewhere; furthermore
there is no way you get a result 30-50% different from [2] or you or [2]
have a problem. However the "GOOD" Fluka numbers for TARC are those in the
TARC papers, compare with those ones!
About NESSI: I cannot confirm your number, however NESSI is NOT measuring
neutron production, but rather neutron captures in a Gd loaded
scintillator surrounding the target with a relatively complex efficiency
factor. A further problem unclear in NESSI is
whether there is neutron production in the scintillator due to particles
which are not neutrons. TARC is MUUUUUUUCHHH cleaner in this respect.
Best regards
Alfredo Ferrari
On Tue, 22 Apr 2003, Dipanwita Dutta wrote:
>
>
> We like to clarify the following two points regarding the FLUKA simulation for
> the
> two input files attached (test.inp and cernexp.inp) as we find discrepancies
> with respect to the published works of Refs. [1] and [2].
>
>
> (1)
> We have done simulation with FLUKA 2002 version 1.0 (Jul. -02). The neutron
> production
> per proton (corrected for the corresponding detector efficiency) has been
> presented
> [Table 1] as a function of incident proton beam energy for a cylindrical Pb
> target of length L= 35 cm and diameter d=15 cm and compared with the available
> published results of different other Monte Carlo codes and results from NESSI
> Experiment (Ref. [1]).
>
>
> Table 1 Comparison of neurtron yield fron FLUKA with other Monte-Carlo codes
> and experimental results:
> --------------------------------------------------------------------------------
> --
>
> Beam HERMES LCS Experiment
> FLUKA
> Energy <------------------> <------------------> <------------------->
> <----->
> (GeV)
> <Mn> Preac Nn/p <Mn> Preac Nn/p <Mn> Preac Nn/p
> Nn/p
> 1.2 21.4 0.867 18.5 22.2 0.863 20.3 22.2 0.848 18.8
> 16.6
> 1.8 29.2 0.869 25.4 31.2 0.864 26.9 30.5 0.853 26.0
> 23.3
> 2.5 37.7 0.865 32.6 40.5 0.860 34.8 38.4 0.848 32.6
> 29.5
>
> We obseved that the neutron multiplicity from FLUKA simulation are lower than
> the other MC codes as well as the experimental values (NESSI). We want to
> confirm whether
> our results are O.K. as we don't have any published results from FLUKA for the
> above dimension of the Pb target. The input file we used is attached (test.inp).
>
>
> (2)
> We tried to compare our FLUKA simulation output with the published result
> from Ref. [2] which discuss about the comparison of FLUKA and LCS simulations
> for the target used in the TARC experiment.
>
> In TARC experiment Pb target used of dimension 3.3 X 3.3 X 3 m3 and
> proton beam of 2 cm diameter was guided into the target through a blind
> hole of diameter 7.7 cm and length 120 cm .
>
> Results of FLUKA and LCS simulation codes is given in the table (Ref.[2]).
>
> Proton Energy FLUKA LAHET FLUKA
> (GeV) (Ref. [2]) (Ref. [2]) (our results)
> 0.7 18.75 21.20 14.33
> 1.0 31.01 35.19 22.46
> 2.0 68.34 75.75 43.86
>
> We observe discrepancy between the published result (Ref. [2]) and our
> simulation using FLUKA-2002.The input file we used is also attached for your
> verification (cernexp.inp).
>
> Reference:
> [1] D. Filges et al. ISSN 1433-559X, ESS 118-08-T. Aug 2001, A. Letourneau
> et al. NIM B 170 (2000) 299.
> [2] Hashemi-Nezhad et al. Kerntechnik 66 (2001) 1.
>
> ----------------------------------------------------------------------------
> | Dipanwita Dutta | Phone: 91-22-25592041 (Off.) |
> | Scientific Officer | 91-22-25589546 (Res.) |
> | Nuclear Physics Division | |
> | Bhabha Atomic Research Centre | Email: ddutta@apsara.barc.ernet.in |
> | Trombay, Mumbai-400085, India | dutta_dipanwita@rediffmail.com |
> ---------------------------------------------------------------------------
>
>
> ----- End forwarded message -----
>
>
>
>
> -------------------------------------------------
>
-- +----------------------------------------------------------------------------+ | Alfredo Ferrari || Tel.: +41.22.767.6119 | | CERN-AB || Fax.: +41.22.767.7555 | | 1211 Geneva 23 || e-mail: Alfredo.Ferrari@cern.ch | | Switzerland || Alfredo.Ferrari@mi.infn.it | +----------------------------------------------------------------------------+
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