[gate-users] Arbitrary Beta Spectrum

[Eric Vandervoort]

Hello,
Sorry for the bombardment of long emails. I have found work-around for the
arbitrary beta spectrum problem but I still have two minor questions. It
might be easier to understand if I explain what I'm trying to do. I
wanted to simulate the distribution of positrons as a function of energy
for Ge-68. It turned out to be simpler to just add the Ge-68 spectrum
directly to the source code using the F-18 and O-15 beta-spectrum code as
a template. This seemed to work nicely and I am no longer trying to use
the ../gps/energytype Arb command.

Now I'm simulating a Ge-68 line source and I expect that some of
the positrons will escape the line source material and annihilate in the
simulated gantry material and/or detector crystals. So here are my two
questions:

1. Will GATE record energy deposited by positrons in a crystalSD (and
the interactions that happen afterwards) or are they only sensitive to
energy deposited by gammas?

In my line-source simulations using the new Ge-68 spectrum. I frequently
get the following warning:
[GateTrajectoryNavigator::FindAnnihilationGammasTrackID]  WARNING :
positron found and photonID vector size: 1

2. Should I be concerned about this warning?

I think this means that the positron escaped without interacting from
some object but I can't really follow what's going on in
GateTrajectoryNavigator.cc. I also get the same warning using the other
built-in Beta spectra (F-18 and C-11).

Thanks Again,
Eric