Re: [fluka-discuss]: Inconsistency between fluka and ESTAR results

From: Paola Sala <>
Date: Sun, 19 Jan 2020 16:01:40 +0100

Dear Hamideh,

the CSDA range is (quoting ESTAR) a very close approximation to the
average path length traveled by a charged particle as it slows down to

CSDA range does not coincide with the projected range: average value of
the depth to which a charged particle will penetrate in the course of
slowing down to rest.

For low energy electrons in high-Z material the difference between CSDA
and projected range is large, since electrons can scatter a lot.

Hope this helps

> Dear FLUKA experts
> For simulating a beam stop for a 150 MeV electron beam, I have considered
> this geometry: A graphite cylinder with length of 5 cm and radius of 3 cm
> is inserted at the end of a recess of 12 cm length to act as a soft stop
> to reduce the back-scatter, this section followed by 3 cm copper and 26 cm
> steel as a beam dump.
> In the physics part of my input, I activated the PHOTONUC card for all
> energies and the sdum of PRECISIO for the DEFALTS card.
> According to the fluka results, all primary electrons are stopped in about
> 2 cm of copper while I expected at least 3 cm (by considering the effect
> of graphite in attenuating the electrons) to 3.5 cm of copper stops them
> according to CSDA range at
> What is the reason for this inconsistency?
> Best Regards
> Hamideh
> __________________________________________________________________________
> You can manage unsubscription from this mailing list at

Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148

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Received on Sun Jan 19 2020 - 17:52:16 CET

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