ATLAS Extensions¶

FullSimLight is an experiment agnostic detector simulation tool that has been implemented and is mantained by the ATLAS collaboration. All the ATLAS specific customizations are available at the ATLAS Extensions repository that is linked to the GeoModel repository as a git submodule. In order to have the corresponding code cloned inside the GeoModel repository the user would need to clone recursively the main repository.

If you still didn’t clone the repository you can clone it recursively:

git clone --recursive https://gitlab.cern.ch/GeoModelDev/GeoModel.git

Alternatively, if you already cloned the GeoModel repository, it will be sufficient to type the following commands from the main repository folder:

git submodule init
git submodule update

A flag is available to build the ATLAS extentions (by default OFF) and it should be turned ON in order to build all the extensions:

cmake ../ -DGEOMODEL_BUILD_ATLASEXTENSIONS=ON -DGEOMODEL_BUILD_FULLSIMLIGHT=ON

A configuration file atlas-conf.json with all the ATLAS specific customizations is provided with the ATLASExtensions and will be installed under /share/FullSimLight/ATLAS.

To run FullSimLight with the ATLAS experiment settings you need a geometry file describing the full ATLAS detector and the ATLAS magnetic field map. These files can be downloaded as explained in the following sections. However please note that they are available only under CERN SSO. If you experience problems with downloading those files please contact the geomodel-core-team

ATLAS Geometry File¶

Some ATLAS geometry SQLite and .gdml files are available at the following link, only working under CERN SSO. They describe the whole geometry tree of different tags used during the different LHC runs. You can select your favourite one and use it with fullSimLight! For example:

wget https://geomodel.web.cern.ch/atlas-geometry-data/geometry-ATLAS-R3S-2021-03-02-00.db

ATLAS Magnetic Field Map and plugin¶

This folder contains the ATLAS magnetic field map implementation. It uses a magnetic field map data file that is available at the following link and can be downloaded with wget:

wget https://geomodel.web.cern.ch/atlas-magnetic-field/bmagatlas_09_fullAsym20400.data

LAr Custom Solid Extension¶

This folder contains the LArCustomSolid Extension that describes the ATLAS LAr EMEC custom shape. The LAr EMEC custom shape extension is build starting from a copy of the corresponding code in the Athena repository. To keep the code of the LArCustomSolid Extention synchronized with the latest available version in the Athena repository, just run the autonomous-lar.sh script.

Run ATLAS Simulation!¶

Now you’re ready to simulate the ATLAS detector in Geant4 with its real magnetic field map. You only have to run the following:

./fullSimLight  -g geometry-ATLAS-R3S-2021-03-02-00.db -c atlas-conf.json