RE: increase in probability of particle production in N-N collisions

From: Kiseleva, Anna <>
Date: Thu, 18 Feb 2010 12:09:37 +0100

Hello Giuseppe.

I tried such LAM-BIAS:


It works. I collect now big statistics in order to compare new data with
old. The question: do I need additionally to normalize new data which
I will get with LAM-BIAS in order to have the same doses as for
data without LAM-BIAS?

Best regards

-----Original Message-----
From: on behalf of Giuseppe Battistoni
Sent: Mon 01-Feb-10 11:32 PM
To: Kiseleva, Anna
Subject: RE: increase in probability of particle production in N-N collisions
Dear Anna
I had not time to enter in full detail in your problem. However there is
the suspicion that everything is due to the fact that you have a very thin
target. Therefore it is natural that only a very very small fraction of
primary interacts. By means of a MonteCarlo like FLUKA you can
solve the problem by using "biasing". In particular you can artificially
increase the probability of interaction and this will be compensated by
a proper weight through all the process, including the scoring.
Therefore I suggest in your case to try such a biasing. It can be
introduced with the LAM-BIAS command with the SDUM=INEPRI.
In that case the inelastic nuclear interaction length will be
reduced by a factor specificed by |WHAT(2)| (the actual value
is your choice!), With INEPRI this is applied only to
primary particles
        Let us know in case

Please try this and let us know.

Please read carefully the manual for the use of LAM-BIAS.

On Mon, 25 Jan 2010, Kiseleva, Anna wrote:

> Hello Giuseppe.
> The problem, wich I have now is following.
> My colleague, Denis Bertini, started the FLUKA calculation for CBM, but as a input for FLUKA he used UrQMD generated particles (SOURCE). The example of the simulation results you can see eDencity.jpg. I use the same input (oldCBM.inp), but new FLUKA version and without external generator. I have 877000 beam particles (Au ions), but I can not reproduce the picture eDencity.jpg (see Energy.gif). I don't see any errors in input (I use FLAIR), but the picture is strange.
> Best regards
> Anna
> ________________________________
> From: Giuseppe Battistoni []
> Sent: Mon 25-Jan-10 1:04 PM
> To: Kiseleva, Anna
> Cc:
> Subject: Re: increase in probability of particle production in N-N collisions
> Hello Anna
> Your result looks strange, but maybe we have not fully understood something.
> 1) Are you simulating collisions against a fixed Au target?
> 2) Which secondary particles are you looking for?
> 3) What is the threshold of secondaries that you are requiring?
> Even in fixed target collisions secondary particles are always expected
> in your case, if we
> interpret that such energy is energy/nucleon.
> If instead. you have given 25 GeV as total energy of
> the Au nucleus, then what you report is possible (E/nucleon about
> 25/197 = 126.9 MeV/nucleon)
> Can you send us your input file?
> Best regards
> Giuseppe Battistoni
> Kiseleva, Anna wrote:
> > Dear FLUKA experts,
> > I work in GSI in CBM group. I started to use FLUKA for radiation study.=20
> > Our basic energy is 25 AGeV Au+Au collisions. I have one question.=20
> > If I understand correctly, for such system only 1% of the interactions=20
> > will produce the secondary particles.=20
> > It means, I need high statistics of the events for my study.=20
> > Is there possibility to increase the probability to produce the=20
> > secondary particles? I tried to find self, but without success.
> > =20
> > Best regards
> > Anna Kiseleva
> > =20
> > ---------------------------------------------------------------=20
> > Dr. Anna Kiseleva=20
> > =20
> > B=FCro: C27 2.020
> > Tel.: +49-(0)6159-711304=20
> > FAX.: +49-(0)6159-713622=20
> > E-mail:
> > =20
> > CBM
> > Gesellschaft fur Schwerionenforschung mbH=20
> > Planckstrasse 1,=20
> > D-64291 Darmstadt=20
> > ---------------------------------------------------------------
> >
Received on Fri Feb 19 2010 - 18:04:16 CET

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