Caro Giuseppe,
in fact your comparison is not indicative as the result with errors should
be compared for equivalent execution times.
Second I realized you just one bin in the USRBIN having at the same time a
pencil beam (dimensionless) which will help you clearly in having the value
you want with fewer primaries.
I'm not sure anymore biasing the decaying products (LAM-BIAS) will help you
more in case you care interested in having just one number out of the
simulation.
Best
V.
On Tue, Nov 25, 2014 at 4:32 PM, Giuseppe Prestopino <
giuseppe.prestopino_at_uniroma2.it> wrote:
> Dear Vittorio,
>
> Thank you for the answer. I repeated my simple simulation and these are
> the complete results for some scored quantities:
>
> 10000 primaries, 4 cycles. USRBIN X-Y-Z, 1bin along each volume dimension
>
>
>
> -- MULSOPT disabled (total multiple scatt. = 6.265E+4, single scat. = 0)
> 0.05 ms/ primary
>
> DPA-SCO 2.7064E-013 (err. 1.6351E-003%)
>
> DOSE 1.8507E+006 (err. 1.3555E-002%)
>
> NIEL-DEP 4.4372E+003 (err. 1.5940E-003%)
>
> -- MULSOPT enabled (total multiple scatt. = 0, single scatt. = 1.8E+6) 30
> ms/ primary
>
> DPA-SCO 2.7044E-013 (err. 1.9703E-003%)
>
> DOSE 1.8502E+006 (err. 1.0102E-002%)
>
> NIEL-DEP 4.4338E+003 (err. 1.9007E-003%)
>
>
>
> Since the results show negligible differences, despite a longer simulation
> time, has single scattering no influence in the scored quantities that I
> have considered? Moreover, I am a beginner user of FLUKA, so, please, can
> you suggest me how to set LAM-BIAS for my specific geometry/ problem, or
> indicate me some example about this bias?
>
>
>
> Best regards,
>
> Giuseppe
>
>
>
> __________________________________________________________
>
> Giuseppe Prestopino
>
> Università di Roma "Tor Vergata" <http://web.uniroma2.it>
>
> Dipartimento di Ingegneria Industriale
>
> Via del Politecnico 1
>
> I-00133 Roma, Italy
>
> Tel. +390672597238
>
> giuseppe.prestopino_at_uniroma2.it
>
>
>
> *Da:* Vittorio Boccone [mailto:dr.vittorio.boccone_at_ieee.org
> <dr.vittorio.boccone_at_ieee.org>]
> *Inviato:* lunedì 24 novembre 2014 22.58
> *A:* Giuseppe Prestopino
> *Cc:* fluka-discuss_at_fluka.org
> *Oggetto:* Re: [fluka-discuss]: radiation damage in thin target
>
>
>
> Dear Giuseppe,
> I don't understand what would you expect? Which is the statistical
> uncertainty of the scoring for both simulations?
>
> All the score dose, DPA, non ionizing energy losses etc are cause by the
> prompt radiation and fragments.
>
> You already implemented most of the suggestion coming from the threads in
> within this reply (one of which is actually your thread):
> http://www.fluka.org/web_archive/earchive/new-fluka-discuss/7375.html
>
> 1) Summarizing: Use LAMBIAS
>
> 2) Coalescent On (you already have it)
>
>
>
> Best,
> Vittorio
>
>
>
> On Fri, Nov 21, 2014 at 6:26 PM, Giuseppe Prestopino <
> giuseppe.prestopino_at_uniroma2.it> wrote:
>
> Dear FLUKA experts,
>
> I am trying to evaluate radiation damage by low energy heavy ions in a
> carbon thin target. I am using 4 MeV (total energy) Carbon primaries that
> hit a small volume target 500 nm thick 20x20 um2. I attach my input files.
> I have set PRECISIO as default and also a MULSOPT card, but I have noticed
> that the results, and error in scored quantities too, are the same both
> with MULSOPT card enabled and with this card disabled. Moreover, if MULSOPT
> is enabled simulation time is about 25 ms/primary, whereas if disabled it
> is 0.05 ms/primary, but there is no difference in results. Is there
> something wrong in my simulation parameters? Many thanks.
>
> MULS. ENABLED MULS. disabled
>
> xyzDOSE 1.8503E+006 1.8513E+006
>
> xyzDPAsco 2.7045E-013 2.7065E-013
>
> xyzRESniel 3.3533E+003 3.3557E+003
>
> xyzNIELdep 4.4340E+003 4.4372E+003
>
>
>
> __________________________________________________________
>
> Giuseppe Prestopino
>
> Università di Roma "Tor Vergata" <http://web.uniroma2.it>
>
> Dipartimento di Ingegneria Industriale
>
> Via del Politecnico 1
>
> I-00133 Roma, Italy
>
> Tel. +390672597238
>
> giuseppe.prestopino_at_uniroma2.it
>
>
>
>
>
Received on Sun Nov 30 2014 - 19:09:51 CET