Hi,
I wish to know how to specify the intensity of two sources used in General Particle Source.
I am trying to add two hemispherical surface sources in Geant4 GPS (one for upward moving particles and the other for downward moving particles). Each set of particles have their own spectrum specified using a histogram. The area under both histograms specify the relative intensity of the two sources. I have put the pseudo code below
/run/initialize
/run/verbose 1
#################
# SOURCE UP
#################
/gps/source/intensity xxup
# Set General Particle Source options
/gps/pos/type Surface
/gps/pos/shape Sphere
/gps/pos/centre 0. 0. 25. cm
/gps/pos/radius 50 cm
/gps/ang/type cos
#Bottom hemisphere (Upwards moving particles)
/gps/hist/type biaspt
/gps/hist/point 0. 0.
/gps/hist/point 0.5 0.
/gps/hist/point 1.0 1.
# Input spectrum
/gps/particle neutron
/gps/ene/type Arb
/gps/hist/type arb
/gps/ene/min 0.1 MeV
/gps/ene/max 300000 MeV
/gps/hist/file neutronup.txt
/gps/hist/inter Lin
####################
# SOURCE DOWN
####################
/gps/source/add xxdown
# Set General Particle Source options
/gps/pos/type Surface
/gps/pos/shape Sphere
/gps/pos/centre 0. 0. 25. cm
/gps/pos/radius 50 cm
/gps/ang/type cos
#Top hemisphere (Downwards moving particles)
/gps/hist/type biaspt
/gps/hist/point 0. 0.
/gps/hist/point 0.5 1.
/gps/hist/point 1.0 0.
# Input spectrum
/gps/particle neutron
/gps/ene/type Arb
/gps/hist/type arb
/gps/ene/min 0.1 MeV
/gps/ene/max 300000 MeV
/gps/hist/file neutrondown.txt
/gps/hist/inter Lin
/run/beamOn 8000000
Should I use /gps/source/ flatsampling ?
or
Should I use /gps/source/intensity/ xxup and /gps/add/source xxdown and compute xxup and xxdown by integrating each spectrum over energy ?
Thanks in advance !