#
### Radiation field defined
### by means of GPS

/gps/verbose 0

### Generates Pencil beam of 200MeV protons by default
### Proton pencil beam is incident on far left side of the phantom 
### (x = -27 cm)and centered in y and z 

/gps/particle proton
/gps/energy 250 MeV
/gps/pos/centre -27. 0. 0. cm
/gps/direction 1 0 0