Hello Anton and thank you very much for your reply
To activate single scattering of electrons/positrons in the gold target only, I would have the following, right?
MULSOPT 1000000001 0.0 3. GOLD MLSH-OFF
Here I chose the maximum possible number of single scatterings but with what logic would I properly choose that? Is it at least equal to the number of mean free paths that fit in the target thickness?
Cheers,
Thomas
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From: Anton Lechner <Anton.Lechner_at_cern.ch>
Sent: Monday, August 12, 2019 8:30:26 PM
To: Primidis, Thomas; fluka-discuss
Subject: RE: EMFFIX limits
Dear Thomas,
According to my opinion the simulation with EMFFIX 0.1% gives an artifact. I suppose that the step size becomes too small for the multiple scattering algorithm. In a scenario like yours (backscattering of low energy electrons), it is strongly recommended to switch on single scattering in order to get accurate results. Note that if a step required by EMFFIX is too small for the multiple scattering algorithm, then the code does not automatically apply single scattering (contrary to te STEPSIZE card). So I would switch on single scattering in the entire target region using the MULSOPT card.
Cheers, Anton
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From: owner-fluka-discuss_at_mi.infn.it [owner-fluka-discuss_at_mi.infn.it] on behalf of Primidis, Thomas [Thomas.Primidis_at_liverpool.ac.uk]
Sent: 20 July 2019 22:19
To: fluka-discuss
Subject: [fluka-discuss]: EMFFIX limits
Dear all,
I am looking for the optimum EMFFIX value for a thin target bremsstrahlung simulation with 60keV electrons entering a 2.5um Au target. My input file is attached.
I did the simulation with various EMFFIX values in gold, from 0.001 to the default 0.2. The results of the transmitted double differential electron fluence are in the attached image. The angular bin of the plot is on its title but the same is seen on all angular bins and of course in the integrated over solid angle plot.
The result with 0.1% is vastly different for <20keV. Is there a reason I would not trust it? Possibly because of the low energy or of the low EMFFIX value itself?
Best regards,
Thomas Primidis
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Received on Tue Aug 13 2019 - 21:22:58 CEST