GPS Command Example 28:

/gps/particle ion
/gps/ion 2 3 1 0.
/gps/pos/type Plane
/gps/pos/shape Square
/gps/pos/centre 1. 2. 1. cm
/gps/pos/halfx 2. cm
/gps/pos/halfy 2. cm
/gps/ang/type iso
/gps/energy 5 MeV

Resulted Distribution Plots: