Hi All,
Hope this is the correct category for my question.
I am trying to implement a custom angular distribution which follows a cos^2(theta) function. I implemented this using GPS as shown below and would like the particles to be emitted from a square plane of 5mx5m and travel along the -z direction. The particles should be emitted only over 2pi solid angle and so I generated my input histogram to be between 0 and pi/2.
My problem is that in the output distribution (included also below) there is a large peak at theta = 0. Does anyone understand why this may be or if I am doing something wrong with my input to GPS?
#########################
/gps/pos/type Plane
/gps/pos/shape Square
/gps/pos/centre 0. 0. -7.5 m
/gps/pos/halfx 5. m
/gps/pos/halfy 5. m
#########################
/gps/ang/type user
/gps/hist/type theta
/gps/hist/point 0.031400000000000 0.999014363996445
/gps/hist/point 0.062800000000000 0.996061341899106
/gps/hist/point 0.094200000000000 0.991152576127576
/gps/hist/point 0.125600000000000 0.984307419706966
/gps/hist/point 0.157000000000000 0.975552859967747
/gps/hist/point 0.188400000000000 0.964923412147018
/gps/hist/point 0.219800000000000 0.952460983310657
/gps/hist/point 0.251200000000000 0.938214707132877
/gps/hist/point 0.282600000000000 0.922240750184547
/gps/hist/point 0.314000000000000 0.904602090494016
/gps/hist/point 0.345400000000000 0.885368269253468
/gps/hist/point 0.376800000000000 0.864615116649703
/gps/hist/point 0.408200000000000 0.842424452900298
/gps/hist/point 0.439600000000000 0.818883765673787
/gps/hist/point 0.471000000000000 0.794085865165688
/gps/hist/point 0.502400000000000 0.768128518190212
/gps/hist/point 0.533800000000000 0.741114062730304
/gps/hist/point 0.565200000000000 0.713149004465634
/gps/hist/point 0.596600000000000 0.684343596869272
/gps/hist/point 0.628000000000000 0.654811406528512
/gps/hist/point 0.659400000000000 0.624668865403611
/gps/hist/point 0.690800000000000 0.594034811789652
/gps/hist/point 0.722200000000000 0.563030021791345
/gps/hist/point 0.753600000000000 0.531776733157907
/gps/hist/point 0.785000000000000 0.500398163355367
/gps/hist/point 0.816400000000000 0.469018023776273
/gps/hist/point 0.847800000000000 0.437760032002088
/gps/hist/point 0.879200000000000 0.406747424041179
/gps/hist/point 0.910600000000000 0.376102468465427
/gps/hist/point 0.942000000000000 0.345945984361004
/gps/hist/point 0.973400000000000 0.316396864993804
/gps/hist/point 1.004800000000000 0.287571609067516
/gps/hist/point 1.036200000000000 0.259583861422348
/gps/hist/point 1.067600000000000 0.232543964985252
/gps/hist/point 1.099000000000000 0.206558525738070
/gps/hist/point 1.130400000000000 0.181729992418764
/gps/hist/point 1.161800000000000 0.158156252612753
/gps/hist/point 1.193200000000000 0.135930246826802
/gps/hist/point 1.224600000000000 0.115139602066983
/gps/hist/point 1.256000000000000 0.095866286365345
/gps/hist/point 1.287400000000000 0.078186285617342
/gps/hist/point 1.318800000000000 0.062169304004094
/gps/hist/point 1.350200000000000 0.047878489180587
/gps/hist/point 1.381600000000000 0.035370183313261
/gps/hist/point 1.413000000000000 0.024693700948542
/gps/hist/point 1.444400000000000 0.015891134588070
/gps/hist/point 1.475800000000000 0.008997188737158
/gps/hist/point 1.507200000000000 0.004039043080755