[Gate-users] difference between /gps/position and /gps/center ?

[lizhi]

Dear GATER:

Would somebody explain me what is the difference between /gps/position and /gps/center ?

Examples in gate users guide said using "/gps/centre" to placement a source.  

Can I use "/gps/position"?


I have check Gate help, it saids:

Command directory path : /gate/source/beamsource/gps/


Guidance :
General Paricle Source control commands.
 The first 9 commands are the same as in G4ParticleGun

 Sub-directories :
 Commands :
 1) List * List available particles.
 2) particle * Set particle to be generated.
 3) direction * Set momentum direction.
 4) energy * Set kinetic energy.
 5) position * Set starting position of the particle.
 6) ion * Set properties of ion to be generated.
 7) time * Set initial time of the particle.
 8) polarization * Set polarization.
 9) number * Set number of particles to be generated.
 10) type * Sets source distribution type.
 11) shape * Sets source shape type.
 12) positronRange * Sets positron range.
 13) centre * Set centre coordinates of source.

.........




But I did not understand the difference.
Thank you for anyone explain me it.

Kind Regards
Zhi LI
VUB