ATLLArBarrel

A Geant4 simulation of the ATLAS LAr Barrel beam test setup.

Fig. - 100 GeV electron passing through the geometry setup.

Table of Contents

1. Project description
2. Authors and contacts
3. Presentations
4. Available datasets and analyses
5. How to
   • Build, compile and execute on Mac/Linux
   • Build, compile and execute on lxplus
   • Debug with lldb
6. G4HepEm integration
7. Using VecGeom

Project description

The project targets a standalone Geant4 simulation of the ATLAS LAr Barrel test beam setup. It is used for Geant4 regression testing and physics lists comparison, as well as for testing speeding up solutions.

• ⏰ Start date: February 2023
• 📌 Status: development

Authors and contacts

• 👨‍🔬 Lorenzo Pezzotti (CERN EP-SFT) - lorenzo.pezzotti@cern.ch
• 👨‍🔬 Supervisor: Alberto Ribon (CERN EP-SFT)

Presentations

• 🗣️ CERN EP-SFT Simulation Meeting 16/5/2023, Preliminary results from the ATLLArBarrel test
• 🗣️ CERN EP-SFT Simulation Meeting 21/3/2023, Towards a Geant4 ATLAS LAr Barrel Validation Test

Available datasets and analyses

We provide datasets and ROOT analyses, as well as instructions for their reproducibility. Ask authors for access to datasets.

ATLLArBarrel	Reproduce data	Reproduce analysis	Comments
v0.3 Dataset #1 tag 0.3_1	Geant4-11.1 ALLArBarrel v0.3 ./ATLLArBarrel -m runcards/run_gps.mac -pl FTFP_BERT -t 8	root -l v0.3/ATLLArBarrelAnalysis.c	Preliminary esults for gamma and pi-, assuming run_gps_output/ is alongside root macro. Created on 15/05/2023.

How to

Build, compile and execute on Mac/Linux

1. git clone the repo

   git clone https://github.com/lopezzot/ATLLArBarrel.git

2. source Geant4-11.1 env

   source /relative_path_to/geant4.11.1-install/bin/geant4.sh

3. cmake build directory and make (using geant4.11.1)

   mkdir build; cd build/
   cmake -DGeant4_DIR=/absolute_path_to/geant4.11.1-install/lib/Geant4-11.1.0/ relative_path_to/ATLLarBarrel/
   make

4. execute (example with run.mac macro card, 2 threads and FTFP_BERT physics list)

   ./ATLLarBarrel -m run.mac -t 2 -p FTFP_BERT

Parser options

• -m macro.mac: pass a Geant4 macro card (example -m run.mac available in source directory and automatically copied in build directory)
• -t integer: pass number of threads for multi-thread execution (example -t 2, default is the number of threads on the machine)
• -p Physics_List: select Geant4 physics list (example -p FTFP_BERT)

Build, compile and execute on lxplus

1. git clone the repo

   git clone https://github.com/lopezzot/ATLLArBarrel.git

2. cmake build directory and make (using geant4.11.1, check for gcc and cmake dependencies for other versions)

   mkdir build; cd build/
   source /cvmfs/sft.cern.ch/lcg/contrib/gcc/8.3.0/x86_64-centos7/setup.sh
   source /cvmfs/geant4.cern.ch/geant4/11.1/x86_64-centos7-gcc8-optdeb-MT/CMake-setup.sh
   export CXX=`which g++`
   export CC=`which gcc`
   cmake3 -DGeant4_DIR= /cvmfs/geant4.cern.ch/geant4/11.1/x86_64-centos7-gcc8-optdeb-MT/lib64/Geant4-11.1.0/ ../ATLLArBarrel/

3. execute (example with TBrun.mac macro card, 2 threads and FTFP_BERT physics list)

   ./ATLLArBarrel -m run.mac -t 2 -p FTFP_BERT

Debug with lldb

1. Compile with debug compiler option, make and start debugger

   cmake -DCMAKE_BUILD_TYPE=Debug -DGeant4_DIR=/path-to/geant4-11.1.0-install/lib/Geant4-11.1.0/ /path-to-dir/ATLLArBarrel/
   make
   lldb

2. Set the lldb target and run with arguments

   target create ATLLArBarrel
   run -m run.mac -p FTFP_BERT -t 2

G4HepEm integration

G4HepEm is a project from the Geant4 Collaboration targeting a library for speeding up the electromagnetic shower generation. G4HepEm is an optional dependency to ATLLarBarrel. The following are istructions for its usage:

1. Install G4HepEm as described in the documentation
2. source geant4 env (example with Geant4-11.1)

   source /path-to/geant4-11.1.0/geant4-11.1.0-install/bin/geant4.sh 

3. Build and compile with G4HepEm

   cmake -DGeant4_DIR=/path-to/geant4-11.1.0/geant4-11.1.0-install/lib/Geant4-11.1.0/ -DG4HepEm_DIR=/path-to/g4hepem-install/lib/cmake/G4HepEm/ -DWITH_G4HepEm=ON ../ATLLArBarrel/
   make

4. Execute (example with run.mac macro, 2 threads and FTFP_BERT physics list)

   ./ATLLArBarrel -m run.mac -t 2 -p FTFP_BERT

Note: the -DWITH_G4HepEm=ON will compile the files under hepemlib/ that are needed to register the G4HepEmProcess. It is possible to use the G4HepEmTrackingManager instead of the G4HepEmProcess using the CMAKE option -DWITH_G4HepEmTracking=ON.

cmake -DGeant4_DIR=/path-to/geant4-11.1.0/geant4-11.1.0-install/lib/Geant4-11.1.0/ -DG4HepEm_DIR=/path-to/g4hepem-install/lib/cmake/G4HepEm/ -DWITH_G4HepEm=ON -DWITH_G4HepEmTracking=ON ../ATLLArBarrel/ 

Using VecGeom

VecGeom is a geometry modeller library and optional dependency to Geant4. ATLLArBarrel can be used with VecGeom. The following are my instructions for VecGeom usage:

1. Install VecGeom (example with VecGeom-v1.2.1)

   cd VecGeom-v1.2.1/
   mkdir build; cd build
   cmake -DCMAKE_INSTALL_PREFIX=/absolute-path-to/VecGeom-v1.2.1/install/ -DVECGEOM_BUILTIN_VECCORE=ON ..
   cmake --build .
   cmake --build . --target install

2. Install Geant4 with VecGeom dependency (example with geant4-11.1.0)

   mkdir buildg4vecgeom; cd buildg4vecgeom
   cmake -DCMAKE_INSTALL_PREFIX=/abolute-path-to/installg4vecgeom -DGEANT4_INSTALL_DATA=ON -DGEANT4_USE_QT=ON -DGEANT4_BUILD_MULTITHREADED=ON -DGEANT4_USE_USOLIDS=ON -DVecGeom_DIR=/abolute-path-to/VecGeom-v1.2.1/install/lib/cmake/VecGeom/ -DGEANT4_USE_GDML=ON /relative-path-to/geant4-11.1.0/
   make -jN
   make install

3. Build ATLLArBarrel

   git clone https://github.com/lopezzot/ATLLArBarrel.git
   source /path_to/installg4vecgeom/bin/geant4.sh
   mkdir build; cd build/
   cmake -DGeant4_DIR=/absolute-path_to/installg4vecgeom/lib/Geant4-11.1.0/ -DVecGeom_DIR=/abolute-path-to/VecGeom-v1.2.1/install/lib/cmake/VecGeom /relative_path_to/ATLLarBarrel/
   make

Note: the instructions above build VecGeom in backend scalar mode. To build it in backend vector use this script, then specify -DVc_DIR when building the simulation.