[gate-users] record hits within block but outside crystals? attach multiple daghters to ecat crystal level?

Paul Vaska vaska at bnl.gov
Fri Sep 17 00:15:52 CEST 2004


I've carefully read the well-written Users Guide, but I still have a 
few detailed questions.

1) It looks like typically the crystals are assigned with 
attachCrystalSD and phantoms with attachPhantomSD and any interactions 
in these are recorded as hits.  What about the material outside the 
crystals, but within the block (such as casing, reflector, ...)?  I 
would like to keep track of any interactions here as well, but these 
seem to fall through the cracks in your definitions?  Can I add the 
block itself with attachCrystalSD or attachPhantomSD, or will this 
confuse the program because the block overlaps with the crystals which 
have already been made sensitive?

2) I'm trying to use the ecat system because it has convenient sinogram 
binning functions, but my detector blocks are not symmetric enough to 
use the cubicArray repeater.  So I divided my block into 2 sets of 
crystals which can be created with this repeater, but I'm having 
trouble attaching both sets to the crystal level within the ecat system 
- an error message implies that you can't attach more than one daughter 
to the crystal level.  If I instead use the cylindricalPET system, I 
suppose I could use the layer0 and layer1 levels for this (even though 
they are side-by-side and not actually layered)?   Since layer0 and 
layer1 are at the same depth, will they be treated the same by the 
adder module and as part of one block by the readout module?

Thanks for any help.


Paul Vaska, Ph.D.
Medical Department, Building 490
Brookhaven National Laboratory
Upton, NY 11973
vaska at bnl.gov (631)344-6228 fax:(631)344-5311

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