The execution control is performed in the GMAD input file through option
and beam
commands. How the results are recorded is controlledby the sample
command.
When the visualization is turned on, it is however controlled through command prompt
and has different syntax (Geant4 syntax).
option
option, <name>=value,...
;
the available options are options are
nperfile beampipeRadius boxSize tunnelRadius beampipeThickness deltaChord deltaIntersection chordStepMinimum lengthSafety turnInteractions thresholdCutCharged thresholdCutPhotons useEMHadronic storeTrajectory stopTracks
For a more detailed description of how the option influence the tracking see Physics
Example :
beam
beam, particle=electron,energy=100, momentum=1,1,1;
sample
To record the tracking results one uses the sample
command:
sample, range=<range>,particle=<particle>,values={value1,value2,...}
the parameters are
element
range
particle
- particle to record. One sample
command activates sampling only for one
particle type
value
x
- horizontal
px
- horizontal momentum
xx
-
y
py
E
- energy
id
- track id. This enables later trajectory analysis.
Example :
sample, element=qd,particle=electron, values={x,px,y,py,e,id };
sample, range=qd/qf:0.1*m,particle=photon, values={x,px,y,py,e,id };
use
use
command selects the beam line for study
use, period=,range=
when bdsim is invoked in interactive mode, the run is controlled by the Geant4 shell. Some examples
/run/beamOn 100
runs the simulation with 100 particles
To display help menu
/help
;
For more details see Geant.