Re: [fluka-discuss]: RE: USRBDX zeroes below 340kev photon beam

From: Francesco Cerutti <Francesco.Cerutti_at_cern.ch>
Date: Thu, 7 Feb 2019 00:04:40 +0100

Hi Alex,

as Mauro suggested, 33 keV (333 keV) is just the photon transport
threshold applied by PRECISIOn (NEW-DEFA) DEFAULTS. You can lower it by
means of EMFCUT, down to 100 eV for secondary photons (for a photon beam
the mimimum recommended energy is about 1 keV, see the manual).

Best
Francesco

**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. +41 22 7678962

On Wed, 6 Feb 2019, Ševčik Aleksandras wrote:

>
> In addition, as alternative, I used USRBIN Beampart in 1x1x2 mesh to
> calculate the attenuation coefficient as well. In this option I the minimal
> energy which still gives the results was 34 keV. If smaller, like 33 keV,
> gives me zeroes even with 29x1E7 primaries. I tried single scattering
> option, but no changes. However, in the manual I read that ~10kev of primary
> photons still should work, so I guess it’s my mistake which I cannot see?.
>
>  
>
> Regards
>
> Alex
>
>  
>
> From: Ševčik Aleksandras
> Sent: Wednesday, 6 February, 2019 21:24
> To: fluka-discuss_at_fluka.org
> Subject: USRBDX zeroes below 340kev photon beam
>
>  
>
> Hello,
>
>  
>
> I was using usrbdx to score the current for linear mass attenuation
> calculation. The values were nicely matched against NIST tables, until I
> reached specifically 0.33 MeV beam value, and despite any change of
> parameter:  a thickness, no of primaries, even a material itself – I get
> zeroes in output usrbdx sum.lis file no matter what I do. Yet 0.34 MeV still
> gives a result. What mistake here I am making? *.inp attached,
>
>  
>
> Regards
>
> Alex
>
>
>

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Received on Thu Feb 07 2019 - 01:04:27 CET

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