[Gate-users] exact behavior of ABSLENGTH or FASTCOMPONENT vectors

[Nicolas HUDIN]

Dear Gate users,

I want to simulate optical photons with gate and I'm actually filling  
my Materials.xml file with the materials I need. My question is about 
the behaviour of the vectors ABSLENGTH, FASTCOMPONENT and RINDEX: does 
GATE make an interpolation of values between the points of the vector? 
Here is an example (I've slightly changed values for the example, it's 
not real BGO values):

If I set my BGO like this:

<material name="BGO">
<propertiestable>
<property name="SCINTILLATIONYIELD" value="8200" unit="1/MeV"/>
<property name="RESOLUTIONSCALE" value="2.75"/>
<property name="FASTTIMECONSTANT" value="320" unit="ns"/>
<property name="SLOWTIMECONSTANT" value="1800" unit="ns"/>
<property name="YIELDRATIO" value="0.98"/>
<propertyvector name="FASTCOMPONENT" energyunit="eV">
<ve energy="2.583" value="0.7"/>
<ve energy="2.8" value="0.3"/>
</propertyvector>
<propertyvector name="ABSLENGTH" unit="m" energyunit="eV">
<ve energy="4.08" value="1"/>
<ve energy="1.84" value="5"/>
</propertyvector>
<propertyvector name="RINDEX" energyunit="eV">
<ve energy="4.08" value="2.1"/>
</propertyvector>
</propertiestable>
</material>

If a photon with an energy of 3eV gets in my BGO, will GATE interpolate 
the ABSLENGTH for my photon from the two defined values?

In the FASTCOMPONENT vector, will gate generate only two kind of photons 
(of 2.583eV and 2.8eV) or can it generate a photon of 2.6eV, with a 
probability interpolated with the two defined photons?

If a photon of 3eV gets in my BGO, which value of RINDEX will GATE use? 2.1?

Thank you very much for your help.

Nicolas HUDIN