The execution control is performed in the GMAD input file through option
and sample
commands. How the results are recorded is controlledby the sample
command.
When the visualization is turned on, it is also controlled through Geant4 command prompt
option
Most of the options in bdsim
are set up by the command
option, <name>=value,...
;
The following options influence the geometry
beampipeRadius
- default beampipe radius [m]beampipeThickness
- default beampipe thickness [m]tunnelRadius
- tunnel Radius [m]boxSize
- default accelerator component size [m]
The following options influence the tracking
deltaChord
- chord finder precisiondeltaIntersection
- boundary intersection precisionchordStepMinimum
- minimum step sizelengthSafety
- element overlap safetythresholdCutCharged
- charged particle cutoff energythresholdCutPhotons
- photon cutoff energyrandomSeed
- seed for the random number generator setting to -1 uses the system clock to generate the seedstopTracks
- if set, tracks are terminated after interaction with material and energy deposit recordedphysicsList
- determines the set of physics processes usedngenerate
- number of primary particles fired when in batch modenperfile
- number of events recorded per filenlinesIgnore
- number of lines to skip when reading bunch filessynchRadOn
- turn on Synchrotron Radiation processsrTrackPhotons
- whether to track the SR photonssrLowX
- Sets lowest energy of SR to X*E_criticalsrLowGamE
- lowest energy of propagating SR photonsminimumEpsilonStep
- minimum relative error acceptable in steppingmaximumEpsilonStep
- maximum relative error acceptable in steppingdeltaOneStep
- set position error acceptable in an integration stepsprodCutPhotons
- standard overall production cuts for photonsprodCutPhotonsP
- precision production cuts photons inelement
prodCutElectrons
- standard overall production cuts for electronsprodCutElectronsP
- precision production cuts electrons inelement
prodCutPositrons
- standard overall production cuts for positronsprodCutPositronsP
- precision production cuts positrons inelement
For a more detailed description of how the option influence the tracking see Physics
beam
The parameters related to the beam are given by the beam
command
beam, <name>=value,...
;
The available parameters are:
particle
- particle name, "e-","e+","gamma","proton", etcenergy
- particle energydistrType
- type of distributiondistrFile
- input bunch file
beam, particle="e+",energy=100*MeV, distrType="gauss";
sample
To record the tracking results one uses the sample
sample, range=<element>;
The sampling plane is then inserted before <element>
Example :
sample, range=d;
Cylindrical sampler of length l
is put around element <element>
at distance <r>
with the command
sample, range=<element>, r=r0, l=l0;
use
use
command selects the beam line for study
use, period=l1,range=q1/q2