[Gate-users] Optical Simulation

[Esteban Venialgo]

Dear Áron Krizsán,

There is an example of a light-tracking on a pixelated detector in the 
Gate's example directory, here is the path:
$GATEHOME/gate_v6.0.0/examples/example_OPTICAL,

I checked the surface definitions that you posted in the previous email, 
and I think that when you define the reflector between the pixel and the 
module, it should be unidirectional. I mean, just defining pixel -> 
module as groundbackpainted is enough. You should not define the 
reflective surface again, between module->pixel (it is not necessary).

btw, I had some problems in this version of  GATE (6.0.0) with optical 
tracking.
http://permalink.gmane.org/gmane.comp.science.opengate.user/1013

            Best Regards, Esteban.

Áron Krizsán wrote:
> Dear GATE users,
>
> We would like to use GATE for optical simulation with an LSO based
> pixelated detector module. However we haven`t found yet a proper way to
> define reflector materials in between the crystal pixels.
>
> The main components of the geometry has been already defined as follows:
> (a module has been created and its material set to teflon,
> in addition, the crystal pixels, coupling layer and apd array are embedded
> into the module)
>
> .
> .
> .
> *# === module ===
> # the module contains the crystal and the two
> # APD arrays.
> /gate/scanner/daughters/name            module
> /gate/scanner/daughters/insert          box
> /gate/module/geometry/setXLength        47.186 mm
> /gate/module/geometry/setYLength        47.186 mm
>
> /gate/module/geometry/setZLength        14.877 mm
> /gate/module/setMaterial                PTFE
> /gate/module/vis/forceWireframe         1
> /gate/module/vis/setColor               yellow
>
> /gate/systems/scanner/level1/attach     module
>
> # === crystal array ===
> /gate/module/daughters/name             crystal
> /gate/module/daughters/insert           box
> /gate/crystal/geometry/setXLength       1.27 mm
> /gate/crystal/geometry/setYLength       1.27 mm
> /gate/crystal/geometry/setZLength       12.0 mm
> /gate/crystal/setMaterial               LSO
> /gate/crystal/placement/setTranslation  0 0 -1.3615 mm
> /gate/crystal/vis/setColor              red
>
> /gate/crystal/repeaters/insert cubicArray
> /gate/crystal/cubicArray/setRepeatNumberX 35
> /gate/crystal/cubicArray/setRepeatNumberY 35
> /gate/crystal/cubicArray/setRepeatNumberZ 1
> /gate/crystal/cubicArray/setRepeatVector  1.346 1.346 0 mm
> .
> .
> .
>
> *
>
> A second question would be the surface definition between the reflector
> material and the
> crystals. We used the followings: *
>
> /gate/crystal/surfaces/name             crystal_module
> /gate/crystal/surfaces/insert           module
> /gate/crystal/surfaces/crystal_module/setSurface polished_teflon_wrapped2
>
> /gate/module/surfaces/name              module_crystal
> /gate/module/surfaces/insert            crystal
> /gate/module/surfaces/module_crystal/setSurface polished_teflon_wrapped2
> .*
> .
> .
>
> Where *polished_teflon_wrapped2* means a surface which is defined as
> follows:
>
> *<surface name="polished_teflon_wrapped" type="dielectric_dielectric"
> sigmaalpha="0.1" finish="groundbackpainted">
>     <propertiestable>
>       <propertyvector name="SPECULARLOBECONSTANT" energyunit="eV">
>         <ve energy="4.08" value="1"/>
>         <ve energy="1.84" value="1"/>
>       </propertyvector>
>       <propertyvector name="SPECULARSPIKECONSTANT" energyunit="eV">
>         <ve energy="4.08" value="0"/>
>         <ve energy="1.84" value="0"/>
>       </propertyvector>
>       <propertyvector name="BACKSCATTERCONSTANT" energyunit="eV">
>         <ve energy="4.08" value="0"/>
>         <ve energy="1.84" value="0"/>
>       </propertyvector>
>       <propertyvector name="RINDEX" energyunit="eV">
>         <ve energy="4.08" value="1"/>
>         <ve energy="1.84" value="1"/>
>       </propertyvector>
>       <propertyvector name="REFLECTIVITY" energyunit="eV">
>         <ve energy="4.08" value="0.95"/>
>         <ve energy="1.84" value="0.95"/>
>       </propertyvector>
>       <propertyvector name="EFFICIENCY" energyunit="eV">
>         <ve energy="4.08" value="0"/>
>         <ve energy="1.84" value="0"/>
>       </propertyvector>
>     </propertiestable>
>   </surface>*
>
> Could You help us please what would be the proper way to define a reflector
> surface, or which properties need to be updated or ignored in the upper
> script ?
>
> In addition can You help us please on reflector definition at large, for
> optical simulatons
> according to Your experience?
>
> With many thanks,
>
> Aron
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