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I exclude categorically that in a region binning a division by the volume be
executed. If what you say is right (and I have some doubts), it can only mean
that the total tracklength is the same for all sizes of the block: that is,
the block is always large enough to contain all particle trajectories, and
no particle escapes.
An easy check can be done by defining binnings with a single bin, of the same
size of the region occupied by the block. You will see that the result will
change, because the same tracklength will be divided by different volumes.
Alberto
On Wed, 5 Jun 2013, Francesco Collamati wrote:
> Thanks for the clarifying reply, but I still have some troubles in
> making it work.
> I have written a simulation in order to test this volume normalisation.
> I attach it: it is a simple lead block with an electron source (in
> order to have all the energy detected).
> With a variable, I've tried to change one dimension of the block to se
> if the dose eq in the output changes with it. Anyway, for all the three
> configuration I obtain the same exact value, suggesting the division per
> the volume is automatically executed.
> What am I missing?
> Thanks again
>
> Francesco
>
> Il 2013-06-01 20:59 Anna Ferrari ha scritto:
>> Hello Francesco,
>> There is no contradiction! The "truth" is both what is written in the
>> manual AND what is written in the answer you found on the FLUKA
>> discussion list.
>>
>> FLUKA calculates dose equivalent multiplying fluence (in part/cm^2)
>> by fluence-to-dose-equivalent conversion coefficients (in
>> pSv/(part/cm^2)).
>> As written in the manual, binning by region does not give you a
>> result normalized by volume: this means it does not give you a
>> fluence
>> but a particle tracklength. To get the fluence you need to divide
>> yourself the tracklength by the region volume. For other kinds of
>> binning this is not needed, because the division by the bin volume,
>> which is calculated analytically, is done by the program.
>> The multiplication by the the fluence-to-dose-equivalent conversion
>> coefficient is done by the program via the AUXSCORE command, in the
>> same way as for other kinds of binning.
>>
>> Summarizing:
>> - Cartesian or cylindrical binning:
>> dose equiv. in pSv = tracklength in cm / volume in cm3 (DIVISION MADE
>> BY THE PROGRAM) * fluence-to-dose-equivalent conversion coefficient
>> in
>> pSv/(part/cm^2)
>> - Region binning:
>> dose equiv. in pSv = tracklength in cm / volume in cm3 (DIVISION DONE
>> BY YOU) * fluence-to-dose-equivalent conversion coefficient in
>> pSv/(part/cm^2)
>>
>> Hope it helps to clarify,
>> regards,
>> Anna
>>
>> Am Sat, 1 Jun 2013 14:44:32 +0200 schrieb Francesco Collamati
>> <francesco.collamati_at_roma1.infn.it>:
>>> Hello Fluka Users
>>> I'm writing (again!) because in the understanding of the meaning of
>>> my simulation output I came across a doubt I was not able to resolve.
>>> I am using a USRBIN scoring (of DOSE-EQ) with Region binning.
>>> According to the manual, this should give a result which is not
>>> normalized per volume, but only per primary particle.
>>> However, i found my result quite different from the one expected,
>>> and googling a bit I found this fluka discussion
>>> (http://www.fluka.org/FLUKA/web_archive/earchive/new-fluka-discuss/4590.html)
>>> in which it is reported:
>>> This means that with the region binning option you will not get the
>>> average fluence in the volume (in part/cm^2), but the total
>>> tracklength in the selected region. To get the fluence and finally the
>>> correct average dose equivalent (always in pSv/primary) you have to
>>> divide offline by the volume.
>>> so, which is the truth!?
>>> how can i get the total eq-dose in a certain region!?
>>> thanks again
>>> Francesco
>>
>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> Anna Ferrari
>> Institute of Radiation Physics
>> Helmholtz-Zentrum Dresden-Rossendorf e.V.
>> Bautzner LandstraÃ?e 400
>> D - 01328 Dresden (Germany)
>> Tel. +49 351 260 2872
--
Alberto Fasso`
SLAC-RP, MS 48, 2575 Sand Hill Road, Menlo Park CA 94025
Phone: (1 650) 926 4762 Fax: (1 650) 926 3569
fasso_at_slac.stanford.edu
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Received on Wed Jun 05 2013 - 16:04:33 CEST