/run/numberOfThreads 1
/run/verbose 1
/random/setSeeds 1 1
/vrt/numberOfSplit 200
/detector/diameter 6.0 nm
/detector/length   10.0 nm

/run/initialize

/gun/particle alpha
/gun/position 0 20 0 nm
/gun/direction 0 -1 0
/gun/energy 4 MeV 

#/run/beamOn 1625
/run/printProgress 10
/run/beamOn 100