Process MCEG

  • How to run MCEG files throught the Software

  • What are the requirements and limitations for the MCEG

  • How to convert files to the right format

  • How to apply beam effects and crossing angle

MCEG Overview

Hepmc in software stack

Athena full simulation and reconstruction stack accepts only HepMC2 and HepMC3 as an input format. The reason for that is that support for many formats on simulation/reconstruction level leads to increasing number of bugs witch are difficult to mitigate with testing because of the combinatorics. It is much easier in terms of testing, robustness and reprodusobility to have a reliable chain that works with one (universal) format and have well tested standalone satelite conventers, that allow to work with different MCEG software (see the next picture).

Hepmc conversion in the software stack

  • Converters allow to convert other formats to HepMC

  • Afterburner applies crossing angle and beam effects

Convert MCEG

Currently there are 2 packages that allow to convert different MCEG to HepMC

  • EicSmear - and old (means well tested) and reliable package

    that allows to convert various (and especially old) MCEG to HepMC format. Instruction how to convert to HepMC It is recommended to use EicSmear especially for BNL RootTree files.

  • mcconv - new and less reliable, but kind of easier

    to use for users and also has convenient python API. mcconv correctly works with GEMC LUND (Clas12) format.

Example converting CLAS12 file to HepMC

# install mcconv
pip3 install --upgrade mcconv

# if there is a sertificate problems
python3 -m pip install --trusted-host pypi.python.org --trusted-host files.pythonhosted.org --trusted-host pypi.org --user -U mcconv

# Add home bin directory to the PATH environment variable
export PATH=~/.local/bin:$PATH

# convert lund gemc
mcconv input.txt -i lund_gemc -b 10x100 -v

# File from example
mcconv /work/eic/mc/meson_MC/OUTPUTS/0mrad_IR0/nov_2021/pi_n_10.0on100.0_x0.0010-1.0000_q1.0-100.0_lund.dat -v -p 1000

Crossing angle and beam effects

In order to apply crossing and beam effects to existing HepMC files EIC Afterbur is to be used. The package provides framework independent well validated crossing angle and beam effects C++ library and HepMC file converter (abconv) for Electron Ion Collider.

Physics simulated:

  • Crossing angle

  • Beam effects (divergence, crabbing kick, etc.)

  • Vertex spread (position, time)

Please follow the instruction of how to use the afterburner.

Using converters and afterburner

Both converters and aferburner are parts of the container. And could be used from JLab and BNL farm. Follow singularity chapter.