Dear Payvand,
the statistical error (provided by the code from the comparison of
different cycles) may become negligible for some problems, if the achieved
statistics is large enough. But this evidently does not mean that the
result is 'exact', since one has to wisely consider the systematic error
on top of that, related to the accuracy of your model (geometry and
material description, threshold settings, scoring resolution, etc) and the
physics implementation. In your case (isotope decay and purely
electromagnetic dose), the uncertainty may be limited (still I'm not sure
that adopting different electron thresholds is a good idea, since you
break the electron equilibrium at material boundaries), but obviously the
code cannot give you a direct quantitative estimate of the systematic
error.
Kind regards
Francesco
**************************************************
Francesco Cerutti
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
tel. +41 22 7678962
On Mon, 28 Jan 2019, P. Taherparvar wrote:
> Dear Dr. Andrea Fontana,
> Thanks for your response.
> I have attached the corresponding input file. Indeed, I want to calculate the statistical error (uncertainty) in dose output for each of scoring rings.
>
> Best Regards,
> Payvand
>
>
>
>
> ----- Original Message -----
> From: "Andrea Fontana" <andrea.fontana_at_pv.infn.it>
> To: <p.taherparvar_at_guilan.ac.ir>, fluka-discuss_at_fluka.org
> Sent: Monday, January 28, 2019 2:55:03 PM
> Subject: Re: [fluka-discuss]: Error percent
>
> Hello,
> the error calculation depends on the binning chosen for the
> USRBIN card (e.g. cartesian, spherical...) and also by its
> granularity (you might have low statistics or empty bins).
> In Flair, which projection did you choose the get the output
> file (1D, 1d max)? Also make sure you enter the region volume
> when scoring dose.
>
> Regarding the splitting of the runs with SPAWN, this works since
> it creates different cycles on the different cores of your CPUs:
> however the suggested way is to use the cycle number in the
> Flair button panel.
>
> If you send your input file, we can cross check the results.
>
> This threads can be helpful:
>
> - http://www.fluka.org/web_archive/earchive/new-fluka-discuss/10107.html
> - http://www.fluka.org/web_archive/earchive/new-fluka-discuss/8955.html
> - http://www.fluka.org/web_archive/earchive/new-fluka-discuss/8955.html
>
> Kind regards,
> Andrea
>
>
>> Dear FLUKA expert,
>>
>> I want to calculate the uncertainty in dose calculation.
>> I used FLUKA code (with flair) and USRBIN card, with 10^7 primary and
>> SPAWN:5.
>> In output results, Column 4 in text viewer in flair is related to the
>> dose error.
>> As I saw in flair course, this error expressedin "percent".
>> For example, I have; dose: 0.00848 and error (Column: 4 in output):
>> 0.042. With this results,Is dose uncertainty about
>> 0.04%?.the/uncertainty/is/too small!!!/
>> Further, what isuncertainty in the cross-section data?
>
> --
> ========================================================================
> Dr. Andrea Fontana tel: +39 0382 987991
> Istituto Nazionale fax: +39 0382 423241
> di Fisica Nucleare
> Sezione di Pavia e-mail: andrea.fontana_at_pv.infn.it
> Via Bassi 6 web : www.pv.infn.it/~fontana
> 27100 PAVIA, Italy
> ========================================================================
>
>
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Received on Wed Jan 30 2019 - 11:25:57 CET