Release 2.3

Physics Processes

  • added scintillation in the material definition, both in API and in the gemc core. The number of photons emitted has two component (fast and slow) and is proportional two:

    A e^(-t/tfast) + B e^(-t/tslow)

    where A and B are the fast and slow component respectively and are dependent on wavelength, and tfast and tslow are the fast and slow time constant (valid for all wavelengths).

    The following quantities can now be specified in the material API, and will be read by gemc.

    • fastcomponent: vector (wavelength)

    • slowcomponent: vector (wavelength)

    • scintillationyield: number of photons / MeV

    • resolutionscale: scale to control the resolution (multiplies sqrt(N))

    • fasttimeconstant: fast time constant

    • slowtimeconstant: slow time constant

    • yieldratio: relative strength of the fast component

    • rayleigh scattering

  • setting hadronic physics list to “none” by default. User can enable them in the gcard or command line. This way one can choose to run w/o hadronic physics.

  • A map of names to process ID is in place and documented. See Process Names / ID Table.

  • The production cut will now affect all volumes in a system rather than just the sensitive volumes

Run Luminosity

  • added RUN_WEIGHTS option. The argument is a text file with two columns: run number and its luminosity weight. GEMC will distribute the number of events requested among the run list according to their weight. The calibration constants, including status, are re-read from the user databases at each run number change.



  • time resolution is an external parameter “VTRESOLUTION”

  • added bunch sampling of the voltage vs signal time. Data structure name is quantumS, map<int, int>. This is effectively FADC mode 1.


  • added graphing of the FADC signal. The shape and intensity of the signal should be optimized for each detector

  • trigger signal added to hit

  • display of trigger added to trigger gui

  • dropdown menu to decide to plot voltage, trigger, or both

  • added buttons to export a detector or the whole root in gdml format

  • added button to inspect detector in a new window

  • added buttons to print screenshots in png PNG, EPS format

  • added button to write single volumes or all volumes to WRL

Cosmic Ray Model

  • added COSMICRAYS option, small utility macro to show the distribution

  • added COSMICAREA option to define the area where the cosmic ray will go through,


Merging Background

  • with SAVE_ALL_MOTHERS set to 2, all particles generating hits are saved in LUND format

  • adding MERGE_LUND_BG option to merge events from the LUND format.

  • See Saving and merging Geant4 background for details.



  • defaulting SPREAD to phasespace, cos(theta) is flat, not theta, unless flag “flat” is given to the SPREAD option

For the complete list of all changes please visit the changelog.