GPS Command Example 3:

/gps/particle gamma
/gps/pos/type Plane
/gps/pos/shape Rectangle
/gps/pos/centre 0. 2. 1. cm
/gps/pos/halfx 1. cm
/gps/pos/halfy 3. cm
/gps/ang/type iso
/gps/ene/type Pow
/gps/ene/min 2. MeV
/gps/ene/max 10. MeV
/gps/ene/alpha -2.

Resulted Distribution Plots: