[gate-users] ring diameter

Mutanga Theodore muathe02 at student.umu.se
Wed Dec 15 10:29:25 CET 2004

Greetings all

I will like to know how GATE calcultes the scanner radius, I designed a
macro for the DST geometry (ring diameter 88.6 cm)  but when I rand
the /gate/systems/describe command I found out that the scanner radius was
88.7 cm instead , how is that so ?
For the system, I used the ecat system with and inner radius of 44.3 for
the DST camera.

Secondly is that the axial sampling interval I was hoping for is 3.27 mm
but I don't find this in the system description,

Also I found out upon zooming , in the ecat scanner example that the block
size in the axial direction extends out of the outer radius of the
scanner, this only appears when you zoom in on this portion, I wonder if
its a problem.
So for my own design, I had to add a few mm's to Rmax to ensure that the
blosks are fully enclosed in the axial direction.

              GATE object:        'systems/ecat/crystal'
                Attached to volume: crystal
                Nb of children:       0
 >> geometrical design type: 1
 >> ring diameter: 88.7 cm
 >> block axial pitch: 3.92501 cm
 >> block azimuthal pitch: 5.21739 degree
 >> block tangential size: 3.925 cm
 >> block axial size: 3.925 cm
 >> crystal axial size: 6.3 mm
 >> crystal tangential size: 6.3 mm
 >> crystal axial pitch: 6.5417 mm
 >> crystal tangential pitch: 6.5417 mm
 >> axial nb of blocks: 4
 >> azimuthal nb of blocks: 70
 >> axial nb of crystals: 6
 >> tangential nb of crystals: 6

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