[Gate-users] Optical Simulation

[Áron Krizsán]

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