Re: [fluka-discuss]: Re: regarding x-ray beam simulation of dental machines

From: Mikhail Polkovnikov <pmk_at_ihep.ru>
Date: Fri, 21 Jul 2017 08:04:32 +0300

On 20.07.2017 20:13, Ševčik Aleksandras wrote:
>
> Thank you both for your attention, and special thanks to Mikhail, for
> your created file which I am using.
>
>
> I added the proposed line, however, my little experiment still shows
> strong deviation between exemplary ref spectrum and scored spectrum,
> see attached files.
>
>
> I also attach all the input files. Where the problem could be?
>
>
> A.
>
> ------------------------------------------------------------------------
> *From:* Eleftherios Skordis <eleftherios.skordis_at_cern.ch>
> *Sent:* Thursday, July 20, 2017 10:43:48 AM
> *To:* Ševčik Aleksandras; fluka-discuss_at_fluka.org
> *Subject:* RE: regarding x-ray beam simulation of dental machines
> Hi Alex,
>
> Your points 1 and 3 are correct. My guess is you are not using the
> customised executable when you are running and therefore not
> generating a multi-energetic beam.
>
> Could you please send us your input and output files so I can help you
> further.
>
> Kind regards
>
> Lefteris
>
>
> -----------------------
>
> Eleftherios Skordis
> Dep. EN/STI, CERN
> CH-1211 GENEVA 23
> SWITZERLAND
>
> OFFICE: +41-22-7679541 <tel:%2B41-22-7675461>
> ------------------------------------------------------------------------
> *From:* owner-fluka-discuss_at_mi.infn.it
> [owner-fluka-discuss_at_mi.infn.it] on behalf of Ševčik Aleksandras
> [aleksandras.sevcik_at_ktu.edu]
> *Sent:* 19 July 2017 22:26
> *To:* fluka-discuss_at_fluka.org
> *Subject:* [fluka-discuss]: Re: regarding x-ray beam simulation of
> dental machines
>
> and hello again, sorry for multiple post, but I thought that it's
> always better to try a practical example, so here it is: using the
> attached files and artificially made spectrum.dat for example
> purposes, I simulated 5x1E6 histories and scored the spectra which
> does not look similar, maybe anybody could comment what I misunderstand?
>
>
> Thank you very much,
>
>
> Alex
>
> ------------------------------------------------------------------------
> *From:* owner-fluka-discuss_at_mi.infn.it
> <owner-fluka-discuss_at_mi.infn.it> on behalf of Ševčik Aleksandras
> <aleksandras.sevcik_at_ktu.edu>
> *Sent:* Wednesday, July 19, 2017 9:02:49 PM
> *To:* fluka-discuss_at_fluka.org
> *Subject:* [fluka-discuss]: Re: regarding x-ray beam simulation of
> dental machines
>
> Addition: I was able to find the answer to 2nd question, it contains
> pairs of values of energy in keV and flux in photons per second, so it
> can be ignored.
>
>
> A.
>
> ------------------------------------------------------------------------
> *From:* Ševčik Aleksandras
> *Sent:* Wednesday, July 19, 2017 7:59:02 PM
> *To:* Vasilis Vlachoudis; fluka-discuss_at_fluka.org
> *Subject:* Re: regarding x-ray beam simulation of dental machines
>
> Thank you very much. I looked all through it, however, it is too
> complicated for me to pursue it in right way from very
> beginning without detail step-by-step guidance and clear examples.
> Therefore I am happy that fluka archive helped me to find the
> similar case with example I could probably use for my needs. Yet few
> clarifications are needed:
>
>
> Attached modified source.f and spectrum source file. Also attached
> dental x-ray spectra for reference.
>
>
> 1) Do I correctly understand that this source.f file generates
> polyenergetic photon spectrum, .i.e. such as shown in the attached
> picture?
>
> 2) Could you please help me to understand what exactly is given in
> spectrum.dat? The first number is just a number of bin, and second - ?
>
> 3) Do I understand correctly that in addition I must use BEAM with
> energy set equal to x-ray used kVp, i.e. maximum energy ?
>
>
> Thank you very much,
>
> Alex
>
> ------------------------------------------------------------------------
> *From:* Vasilis Vlachoudis <Vasilis.Vlachoudis_at_cern.ch>
> *Sent:* Monday, July 3, 2017 10:08:55 AM
> *To:* Ševčik Aleksandras; fluka-discuss_at_fluka.org
> *Subject:* RE: regarding x-ray beam simulation of dental machines
> Hi Aleksandras,
>
> my guess is that the best way will be to create a custom source.f routine
> that you sample directly from the spectrum of your x-ray equipment.
>
> Look the advanced course on how to make a custom source
>
> https://indico.cern.ch/event/489973/contributions/2148893/attachments/1271819/1884943/11_AdvancedSources2016.pdf
>
> Cheers
> Vasilis
>
>
> ------------------------------------------------------------------------
> *From:* owner-fluka-discuss_at_mi.infn.it
> [owner-fluka-discuss_at_mi.infn.it] on behalf of Ševčik Aleksandras
> [aleksandras.sevcik_at_ktu.edu]
> *Sent:* Friday, June 30, 2017 16:19
> *To:* fluka-discuss_at_fluka.org
> *Subject:* [fluka-discuss]: regarding x-ray beam simulation of dental
> machines
>
>
> Dear experts,
>
>
> I am interested in the calculation of effective doses during the
> dental -xray procedures. Is it possible to generate a beam only of
> the specific piece of x-ray equipment when manufacturer's parameters
> are known, or should one model all the internal components of the
> machine i.e. the whole x-ray generation process in order to have valid
> results?
>
>
> Sorry if this question too obvious. In addition, I would appreciate
> any links/comments/references that would help me in pursue of this matter,
>
>
> Regards
>
> Aleksandras
>
Dear Alex,


It looks like you didn't compile a source.f routine and didn't run the
modified FLUKA executive file with the modified source routine (see
FM.pdf, Chapter 13, User routines). That is why your simulation uses
only monoenergetic value from the BEAM card!


There is no need to use OPEN card in an input file, when you open file
for reading in source.f (OAUXFI or OPEN calls).


Just use either

1) OAUXFI call in source.f and disable OPEN card

or

2) OPEN card and do not open file for reading in source.f once again.


I prefer first approach nowadays.


As a result your scored spectrum should be OK.



Best regards,

Mikhail





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source_test_24_plot.jpg
(image/jpeg attachment: source_test_24_plot.jpg)

Received on Fri Jul 21 2017 - 08:18:39 CEST

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