#
### Radiation field defined
### by means of GPS 
/gps/verbose 0
/gps/particle e-
/gps/energy 1 MeV
#
/gps/pos/type Volume
#
/gps/pos/shape Para
/gps/pos/halfx 20 cm
/gps/pos/halfy 1 mm
/gps/pos/halfz 100 cm
/gps/pos/centre 0. 30. 0. cm
/gps/direction 0 -1 0