Internal Generator

A primary particle 4-momentum and vertex ranges can be set with the gcard directives:

<option name="BEAM_P"   value="proton, 4.0*GeV, 20.0*deg, 10*deg"/>
<option name="SPREAD_P" value="1*GeV, 10*deg, 180*deg"/>
<option name="BEAM_V"   value="(0, 0, -5)cm"/>
<option name="SPREAD_V" value="(0.1, 10)cm"/>

The above will generate a proton with:

  • momentum between 3 and 5 GeV.

  • θ between 10 and 30 degrees.

  • ϕ between 0 and 360 degrees.

  • vertex z between -10 and 0 cm.

  • vertex radius between 0 and 0.1 cm.

Any gcard directive can be superseed by its corresponding command line. For example:

-BEAM_P="e-, 6.0*GeV, 20.0*deg, 10*deg"
-SPREAD_P="1*GeV, 10*deg, 180*deg"

Particles names

Here’s the list of some relevant particle names:

  • e+

  • e-

  • eta

  • gamma

  • geantino

  • kaon+

  • kaon-

  • kaon0

  • kaon0L

  • kaon0S

  • mu+

  • mu-

  • neutron

  • pi+

  • pi-

  • pi0

  • proton

List of all particles

The following line will print on screen the list of particles (name and ids) that can be used by gemc:

-BEAM_P=show_all