Re: [fluka-discuss]: Question about LAM-BIAS card.

From: Francesco Cerutti <>
Date: Sun, 9 Sep 2018 23:30:09 +0200

Dear Zhefu,

the reliability of your results is indicated by their statistical error.
As the latter exceeds few ten percent, they should be intended as (highly)

The biasing's aim is to get a better (= lower) statistical error on the
quantity of interest for the same CPU time. Therefore, its effectiveness
shall not be evaluated for the same number of primary particles, rather
for the same CPU time.

Of course, ideally, the biasing absence can be compensated by a larger CPU
time to get the same convergence.

The 0.02 reduction of the inelastic interaction length is a reasonable
value to start with. But the results have to be judged according to the
respective statistical error, as said at the beginning.

Best regards


Francesco Cerutti
CH-1211 Geneva 23
tel. +41 22 7678962
fax +41 22 7668854

On Fri, 7 Sep 2018, lzf neu wrote:

> Hi all,
> I want to consult you two questions about LAM-BIAS card please:
> 1) The electron energy is 8 GeV, I am confused that is it reasonable to
use LAM-BIAS card combined with photonuc card for the shielding design.
> I compared the result with and without LAM-BIAS card for the same number
of simulation particles, if with LAM-BIAS card, the production of neutrons
is enchanced by biasing the inelastic nuclear interaction length of photon.
> I am confused that what is the resonable choice for the shielding
design. Is the simulation result with LAM-BIAS card the realistic one?
> If I run the simulation without LAM-BIAS card for enough particles, can
the result be equal to that of with LAM-BIAS card one?
> 2) According to the fluka manual about LAM-BIAS card: lambda value is in
the order of 0.01~0.05 as the shower induced by photon or electron with
1GeV energy, and that of 0.1~0.5 with 1TeV.
> What is the reasonable lambda value setting when electron energy is 8
GeV and is it reasonable to set 0.02 for shielding design?
> Any help will be appreciated and thanks in advance!
> Zhefu
> (???ځ맲r?'~??x%Z?m????~[???i֜r)

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Received on Mon Sep 10 2018 - 01:09:55 CEST

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