[Gate-users] Radiotherapy and physics lists question

[David Sarrut]

Hello,

On Tue, Jan 28, 2020 at 7:27 PM Lana Beck <lana.beck at bristol.ac.uk> wrote:

> Dear Dr Sarrut,
>
> I have a question about the example in your gitbook:
> https://dsarrut.gitbooks.io/gate-exercises/content/exercise4-linac.html
> and the associated code here:
>
> https://gitlab.in2p3.fr/davidsarrut/gate-exercices/blob/master/linac/mac/main-write-PhS.mac
>

the gitbook link is no more maintained, please use:
https://davidsarrut.pages.in2p3.fr/gate-exercices-site/ (for the moment it
is essentially the same).


> If you prefer I can send my question to the gate-users list but as it
> pertained to your gitbook particularly I thought I should email you first.
>

yes I prefer to copy the gate-user list please.


> I was wondering about the line (110) in the example:
> /process/em/setSecBiasing eBrem target 100 100 MeV
>
> However, in the Section 5.2.1.1 in the gate manual it says to use:
> /gate/physics/processes/Bremsstrahlung/activateSplitting e- 100
>
> https://opengate.readthedocs.io/en/latest/cut_and_variance_reduction_technics.html
> and then I guess filters could be used for volume and energy.
>
> Is there a difference in these two methods? Of course the latter one
> requires using:
> /gate/physics/addProcess Bremsstrahlung
> /gate/physics/processes/Bremsstrahlung/setModel StandardModel e-
> /gate/physics/processes/Bremsstrahlung/setModel StandardModel e+
> in order for activateSplitting to work. However I'm not really sure what
> happens when adding the Bremsstrahlung process since eBrem is already
> included in the initialised methods of emstandard_opt3.
>
>
the opengate doc is wrong here and should be updated. Please use the first
macro "setSecBiasing". The second sets of macros are now deprecated and
should not be used.



> I am interested in the electron contamination from the linac head and I
> need a large sample. Hence, I wanted to do something similar for Compton
> Scattering and I'm not sure which method to use.
>

For Compton Scattering, use the same setSecBiasing command but with the
Compton process name. You should find the name of the Compton somewhere in
the Geant4 document, sorry, dont know where ...

David


>
> Any advice would be greatly appreciated.
>
> Kind regards,
> Lana
>
>
> -------------------
> *Dr Lana Beck*
>
> Research Associate in Particle Physics Group
>
> University of Bristol
>
>
> HH Wills Physics Laboratory
> School of Physics
> University of Bristol
> Tyndall Avenue
> Bristol
> BS8 1TL
>
>

-- 
David Sarrut, Phd
Directeur de recherche CNRS
CREATIS, UMR CNRS 5220, Inserm U1206
Centre de lutte contre le cancer Léon Bérard
28 rue Laënnec, 69373 Lyon cedex 08
Tel : 04 78 78 51 51 / 06 74 72 05 42
http://www.creatis.insa-lyon.fr/~dsarrut
_________________________________
 "2 + 2 = 5,  for extremely large values of 2"
_________________________________
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.opengatecollaboration.org/pipermail/gate-users/attachments/20200129/459593a5/attachment.html>