Dear Jonathan,
first of all, maybe it is useful to remember that the distinction between
photon and electron dose does not make sense in reality, because also in the
case of photons the dose is always entirely due to the secondary electrons
that they produce.
When with FLUKA you calculate the DOSE (the energy deposited per unit mass)
due to the photons, you see the effect of the transport threshold that
"forces" the photon below threshold to locally deposit his energy.
When on the other hand you calculate the DOSE-EQ (dose equivalent) due to the
photons, you fold the photon fluence with a set of conversion coefficients
that have been calculated on a proper phantom where, another time, the dose
was entirely due to the secondary electrons produced by photons.
The second thing that it is useful to clarify is that when you compute with
USRBIN a DOSE or a DOSE-EQ (in the second case by selecting the desired set of
conversion coefficient via the AUXSCORE card), you get by default all the
contributions coming from all the particles generated by your primary beam. If
you want to filter the contribution of a certain kind of particles you have to
declare it in the AUXSCORE card.
Coming to your questions, in 1) and 2) there is a bit of confusion between
ambient dose equivalent H*(10), personal dose equivalent Hp(10), effective
dose and sets of conversion coefficients from fluence to dose
equivalent/effective dose. I would suggest to look at this lecture (p. 14-16):
https://www.fluka.org/free_download/course/nea2013/Lectures/18_Activation.pdf
where you can find also a useful reference.
I would summarize that in FLUKA for your needs you can find:
- for ambient dose equivalent calculations: the conversion coefficients
fluence/H*(10), based on ICRP74 values (and values calculated by M.Pelliccioni
for neutrons above 20 MeV).
You explicitly select it via AUXSCORE with sdum=AMB74 (in any case this is the
default choice, you get it by selecting the DOSE-EQ scoring also without
giving the option AUXSCORE).
As said above, by default you get all the contributions to the H*(10).
- for effective dose calculations: conversion coefficients fluence/effective
dose.
They are implemented for three different irradiation geometries (please see
manual and lecture cited above).
The choice sdum=ETW74 selects the coefficients there are obtained by
considering, for each energy bin in each data set corresponding to a certain
kind of particle, the maximum coefficient of anterior posterior, posterior
anterior, right lateral and left lateral geometries.
This set of coefficients is therefore always conservative with respect to the
effective dose (which depends on the irradiation geometry). It is a very good
choice for shielding purposes.
...and now, let's start from the question 1:
1) " If I use USRBIN-DOSE-EQ is it the same as h*(10) (photon ambient dose
only)? Moreover, is it the same as USRBIN with tracking photon and a AUXCORE
card with a routine AMB74? "
No. If you use a USRBIN with what(2)=DOSE-EQ by default you get H*(10) with
all the contributions to the dose equivalent. If you want to isolate the
contribution coming from the photon fluence you have to filter it via
AUXSCORE.
Moreover: a USRBIN with what(2)= PHOTON select the photon fluence, not at all
a dose or dose equivalent.
2) " If I use a USRBIN with tracking of electron (part = electron) and a
AUXCORE card with a routine EWT74 is it the same as the dose Hp(10) for
electron (electron deep dose)?"
No. The personal dose is not implemented in FLUKA and -as clarified before-
has nothing to do with ETW74.
Moreover, "Electron deep dose" has no meaning in this context (I hope I'm
wrong, but I have the suspect that you want to use different quantities for
different contribution to the dose... this has no meaning!).
If you want to do the exercice to separate the electron and the photon
contributions (I would not do), use AMB74 or ETW74 and write a dedicated
USRBIN card for photons (using AUXSCORE) and another one for electrons.
3)" Eventually, if I want the total dose (photon + electron) do I have to use
the URSRBIN-Dose or a USRBIN with tracking ALL-PART with the card AUX-CORE and
the routine EWT74 (or maybe it is the same)?"
I think now it is clear: by using USRBIN with what(2)=DOSE or what(2)=DOSE-EQ
you get by default the total dose. In the dose equivalent case you get by
default the ambient dose equivalent H*(10), if you want EWT74 you have to
select it via AUXSCORE.
Hope this helps,
Regards,
Anna
Am Tue, 20 Aug 2013 15:00:21 +0200 schrieb Jonathan Le Gouestre
<Jonathan.LeGouestre_at_lemerpax.com>:
> 2013 15:00:33 +0200 (CEST)
> Sender: owner-fluka-discuss_at_mi.infn.it
>
> Dear Fluka experts,
>
> I have some questions on the use of USRBIN-Dose and USRBIN-Dose-eq. For my
>problem I simulate a beam of electron in a tungsten target, and I want to
>calculate the total dose and dissociate the contribution of electron and
>bremsstrahlung photons.
>
> My questions are the next:
>
> 1. If I use USRBIN-DOSE-EQ is it the same as h*(10) (photon ambient dose
>only)? Moreover, is it the same as USRBIN with tracking photon and a AUXCORE
>card with a routine AMB74?
>
> 2. If I use a USRBIN with tracking of electron (part = electron) and a
>AUXCORE card with a routine EWT74 is it the same as the dose Hp(10) for
>electron (electron deep dose)?
>
> 3. Eventually, if I want the total dose (photon + electron) do I have to
>use the URSRBIN-Dose or a USRBIN with tracking ALL-PART with the card
>AUX-CORE and the routine EWT74 (or maybe it is the same)?
>
> Maybe there is another method to discriminate electron, photon and total
>dose?
>
> Thank for your answer.
>
> Cheers,
>
> Jonathan.
>
>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dr. Anna Ferrari
Institute of Radiation Physics
Helmholtz-Zentrum Dresden-Rossendorf e.V.
Bautzner LandstraÃe 400
D - 01328 Dresden (Germany)
Tel. +49 351 260 2872
Received on Mon Sep 02 2013 - 09:18:03 CEST