LowPtTracksProject

Generation and reconstruction of low-pT charged particles (pions, kaons, protons) into a toy simulation of the ITS2 and TPC of ALICE, under none or low magnetic field.

reconstruction

• Description: Modification of the example B2a of GEANT4. (will be extended later)

• Requirements:

  • GEANT4

• Interactive usage via Graphical User Interface:

  1. Enter the reconstruction dir and build with bash build.sh
  2. Execute with bash run_gui.sh
  3. Here, you have two options:
     1. Press the /run/beamOn 1 button to inject and propagate particles from the standard input file reconstruction/mc.csv (input file can be changed with commands below). IMPORTANT: don't forget to set the magnetic field if needed (see commands below).
     2. Or, if you want to inject a single particle, you can use the commands /ALICE/pdg_single_part and /ALICE/py_single_part (see below) to set the particle's properties and to not input from file. Then, you can press the /run/beamOn 1 button to inject and propagate it.

  • Available menus:

    • Single Particle: a single particle will be injected with just Py component, choose species "pion / kaon / proton" and momentum magnitude "Py = 25 / 50 / 75 / 100 / 150 / 200 / 225 / 250 / 300 MeV/c"

    • Magnetic Field: choose magnitude of z-component of magnetic field.

    • Viewer : viewer-related options.

    • Style: style-related options.

  • Available commands:

    • /ALICE/input_file <filename> : set input file (default value: reconstruction/mc.csv)
    • /ALICE/traj_file <filename> : set output file containing trajectories info (default value: reconstruction/event<event_id>_traj.csv)
    • /ALICE/its_file <filename> : set output file containing info of hits on the ITS2 (default value: reconstruction/event<event_id>_its.csv)
    • /ALICE/tpc_file <filename> : set output file containing info of hits on the TPC (default value: reconstruction/event<event_id>_tpc.csv)
    • /ALICE/pdg_single_part <pdg_code> : disables input from file, set a single particle instead with the chosen PDG code
    • /ALICE/py_single_part <py> <units> : y-component of the momentum of the single particle to be injected
    • /globalField/setValue <mag_field_vector> <units> : set magnetic field (default value 0 0 0)
    • /vis/ogl/export <filename>.<extension> : export a screenshot of current view as an image file

• Command-line/terminal usage:

  1. Build with bash build.sh
  2. Enter G4Setup_build/
  3. Execute with:

     ./main <MC_CSV> <TRAJ_CSV> <ITS_CSV> <TPC_CSV>
     

     where:
     • <MC_CSV> : path of input file with MC particles (format described below)
     • <TRAJ_CSV> : path of output file containing trajectories info (format described below)
     • <ITS_CSV> : path of output file containing info of hits on the ITS2 (format described below)
     • <TPC_CSV> : path of output file containing info of hits on the TPC (format described below)

• Input:

  • MC-generated particles file (as in reconstruction/mc.csv) with the following format (which corresponds to the output of generator/ and injector/):

  PDG Code, Px (GeV/c), Py (GeV/c), Pz (GeV/c)
  

• Output:

  Three files will be output. Their information can be connected (or linked) via the variable trackID.

  • eventXX_its.csv contains the ITS2 hits information, where each line correspond to a different hit with the following format:

  trackID, layer number, x (cm), y (cm), z (cm), Px (MeV/c), Py (MeV/c), Pz (MeV/c), deposited energy (MeV), generation process
  

  • eventXX_tpc.csv contains the TPC hits information, where each line correspond to a different hit with the following format:

  trackID, x (cm), y (cm), z (cm), Px (MeV/c), Py (MeV/c), Pz (MeV/c), time (ns), deposited energy (MeV), generation process
  

  • eventXX_traj.csv contains the trajectories (or true particle) information, where each line correspond to a different particle with the following format:

  trackID, PDG Code, initial x (cm), initial y (cm), initial z (cm), initial Px (MeV/c), initial Py (MeV/c), initial Pz (MeV/c), parentID, charge
  

injector

• Requirements:

  • ROOT

• Description:

  ROOT macro that generates positive pions, positive kaons, protons, and their corresponding anti-particles, within an uniform distribution in transverse momentum, rapidity and azimuthal angle. It's currently set up to repeat n_times. Information is output in a .csv file.

• Usage:

  root -l -b -q 'injector/GenBox.C("<output_file>")'
  

• Output:

  A single CSV file called will be generated, where each line correspond to a different particle with the following format:

  PDG Code, Px (GeV/c), Py (GeV/c), Pz (GeV/c)
  

tools

• send_production.sh -- bash script to send simulation jobs in batches, via HTCondor.

  • Requirements:

    • ROOT
    • GEANT4

  • Usage:

    ./send_production.sh --sim_dir <sim_dir> --run1 <run1> --run2 <run2> --serv <serv> --outsd <>
    ./send_production.sh --sim_dir <sim_dir> --rn <rn> --serv <serv> --outsd <out_sub_dir>
    where:
    <sim_dir>     = main directory (NOT output directory!)
                    (default: if ${PWD} == tools/, then sim_dir = "tools/.."
                              if not, then sim_dir = ${PWD})
    <rn>          = specific run numbers, separated by comma
                    for example: --rn 0,1,2
    <run1>        = run number of the first job (starting point of loop)
    <run2>        = run number of the last job (end of loop)
    <serv>        = select which machine to use: alice-serv<serv>
                    it can be: 10, 12 or 14
    <out_sub_dir> = subdirectory (it's a string!) within the output directory, for organizational purposes
    
    EXAMPLE:
    ./send_production.sh --run1 1 --run2 100 --serv 10 --outsd 001
    

  • Hard-coded parameters:

    • OUTPUT_DIR : top output directory
    • N_EVENTS_PER_RUN : number of events per run (recommended: 100)

• merge_files.sh -- merge every eventX_mc.csv, eventX_traj.csv, eventX_its.csv or eventX_tpc.csv within a run directory <run_dir> into a single runX_mc.csv, runX_traj.csv, runX_its.csv, or runX_tpc.csv (respectively) by adding the eventID as the first column.

  • Usage: ./merge_files.sh <run_dir>

analysis

(description pending)

• Usage: root -l -b -q ParseCSVFiles(<run_n>), where <run_n> will read the respective run<run_n>_traj.csv, run<run_n>_its.csv, run<run_n>_tpc.csv files, and it will output a single run<run_n>_ana.root file.

generator

(deprecated)

• Requirements: PYTHIA8 (can be easily installed with generator/install_pythia.sh)

• Usage:

  ./main_GenCollision --n <n> --config <config_file> --output <output_dir>
  

  where:

  • --n <n> : number of events to generate
  • --config <config_file> : input configuration file (mandatory), should look like generator/config_pp.cmnd
  • --output <output_dir> : output directory

• Output:

  A single file called mc.csv will be generated in case the number of events is 1, otherwise one eventX_mc.csv file will be generated per each event. In these files, each line correspond to a different final-state particle with the following format:

  PDG Code, Px (GeV/c), Py (GeV/c), Pz (GeV/c)