Re: [fluka-discuss]: Fw: RHOR factor vs CORRFACT

From: chetaine <chetaine_at_fsr.ac.ma>
Date: Tue, 23 Feb 2016 19:15:00 +0000

OK I WILL DISCUSS THE PROBLEM AND IF I GET MORE DETAILS I WILL CONTACT YOU

"Ferreira De Almeida Lourenco, Ana" <am.lourenco_at_ucl.ac.uk> a écrit :

> Hi Chetaine and All,
>
> The purpose of my simulations is to calculate ionization chamber
> perturbation factors for proton beams. For that purpose, I want to
> study first the accuracy of particle transport in FLUKA by
> performing a self-consistency test called the "Fano cavity test".
> "The Fano cavity test is based on the Fano theorem, which states
> that under charged equilibrium conditions, the charged particle
> fluence is independent of the mass density of the media as long as
> the cross-sections are uniform."
>
> Therefore, even if in reality the cross-sections are dependent on
> the mass density, for the purpose of these simulations the cross
> sections must be independent of the density.
>
> Many thanks,
> Ana
>
> ________________________________________
> De: chetaine <chetaine_at_fsr.ac.ma>
> Enviado: 23 de fevereiro de 2016 17:28
> Para: Ferreira De Almeida Lourenco, Ana
> Cc: fluka-discuss_at_fluka.org
> Assunto: Re: [fluka-discuss]: Fw: RHOR factor vs CORRFACT
>
> dear Ferreira
> i am a new user and the question is not very clear but with my little
> experience
> i can say that the cross section that we use is macroscopic cross
> section and macroscopic cross section depend on the number of atoms /cm3
> the density is g/cm3 equivalent to the number of atoms /cm3
> so the cross section depend on the density
> best regards
>
>
> "De Almeida Lourenco, Ana" <am.lourenco_at_ucl.ac.uk> a écrit :
>
>> Dear Fluka experts,
>>
>>
>> I'm sorry to e-mail you again but I was hoping to get some feedback
>> regarding my post from last week (please see below). How can I make
>> sure that the cross sections in the simulations are independent of
>> the density?
>>
>>
>> Any feedback would be greatly appreciated!
>>
>> Many thanks,
>>
>> Ana
>>
>> ________________________________
>> De: Ferreira De Almeida Lourenco, Ana
>> Enviado: 16 de fevereiro de 2016 11:07
>> Para: fluka-discuss_at_fluka.org
>> Assunto: RHOR factor vs CORRFACT
>>
>>
>> Dear Fluka experts,
>>
>>
>> I'm simulating in FLUKA a proton beam (energies ranging from 60-250
>> MeV) on a phantom made of water. The phantom is divided into
>> different water regions with different mass densities (all regions
>> have same composition, same I-value, same Sternheimer density effect
>> parameters).
>>
>>
>> For the purpose of my simulations, I need to have homogeneous atomic
>> properties through the phantom, i. e. the cross sections must be
>> independent of the density. For that, I override the RHOR factor
>> (from MAT-PROP) so RHOR*RHO is the same in all the regions of the
>> phantom.
>>
>>
>> The manual states:
>>
>> WHAT(2) = RHOR factor : this factor multiplies the density of the
>> material(s) when calculating the density effect parameters
>>
>> Is the RHOR factor just used to calculate the density effect on
>> stopping power, or are other density-dependent properties also
>> included?
>>
>> How can I make sure that the cross sections are independent of the
>> density (nuclear interactions, scattering, etc)? By looking at the
>> CORRFACT description it seems to me that this card could do the job
>> but I have been advised in the past to not use it.
>>
>>
>> Any thoughts or suggestions?
>>
>>
>> Many thanks,
>>
>> Ana
>>
>
>
>
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Received on Tue Feb 23 2016 - 22:25:19 CET

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