Hello, I simulated a 45GeV e+ , here the features of the beam
/gps/particle e+ /gps/energy 45 GeV /gps/ene/type Gauss /gps/ene/sigma 0 GeV /gps/pos/type Beam /gps/pos/shape Circle /gps/pos/radius 0. mm /gps/pos/sigma_x 0.3 mm /gps/pos/sigma_y 0.3 mm /gps/pos/centre 0 0 -100 cm /gps/direction 0 0 1
then you see…it’s a gaussian beam having a sigma_x and sigma_y 300um. The beam hit 2 targets… I’m studying the positrons outgoing the targets…
This is a plot of the positrons outgoing the first target (it’s a Be target having hourglass shape and the thickness at the center of the hourglass is 3mm)
On the x axis I plotted
x_ext is the position at the exit of the target and
x_prod is the position of production of the primary positron
On the y-axis I plotted
x' that is the angle at the exit of the target.
You see there is a long line at x=0, as if x_ext=x_prod… my supervisor said me that he thinks that it’s due to the step dimension…then to try to modify the step size…but…how to modify it?
I’ve the StepMax.cc and StepMax.hh but I can’t find a value to modify