a simple simulation of a muon detector made of LiquidO

useful pieces of information

• to source a complete LCG environment: source /cvmfs/sft.cern.ch/lcg/views/setupViews.sh LCG_96 x86_64-centos7-gcc8-opt
  • now implemented in setup_lxplus.sh, where if any additional argument is given the version with debugging info is linked (source setup_lxplus.sh 1)
• original simulation code of LiquidO is here
• to have the mac working, always use ssh -Y and, on your mac, enable “indirect GL” in XQuartz, with the command defaults write org.macosforge.xquartz.X11 enable_iglx -bool true
• documentation on Geometry in Geant4 at this link
• Geant4 example
• Getting started with Geant4

the code

• MUON_DetectorConstruction: where the geometry of the detector is defined
  • remember: for each object one needs:
    • a solid = shape and size
    • a logical volume = solid + properties (material, whether it's sensitive...)
    • a physical volume = location of the object
    • NB the physical volume is placed inside a logical volume somehow, so it seems it's enough to replicate the most external one of them all
• MUON_DetectorMessenger: pass the infoes from the mac file to the Detector Construction
• MUON_OpticalPhotonSD: behaviour of the sensitive detectors in the geome
  • the single elements are identified by the copy number, I think
• the simulation process is composed of a run of events, which are processed in the following hierarchically organised actions:
  • MUON_RunAction: Begin and end of the run
  • MUON_EventAction: Begin and end of an event
  • MUON_TrackingAction: Begin and end of tracking
  • MUON_SteppingAction: At each step in which the tracking process is divided

the geometry

• A single slab of scintillating LiquidO, with square section in the (x,y) plane, is filled in the middle with an array of fibres, parallel to the base surface.
• each readout unit (ru_l) is composed of a fibre and a SiPM, and contains an overall envelope (fiber_env_l)
• each fibre is composed of an outer cladding (fiber_outer_cladding_l), inner cladding (fiber_inner_cladding_l), and core (fiber_core_l)
• each SiPM is composed of an overall volume (ru_sipmt_l) and a sensitive volume (ru_sipmt_sens_l)
• there's a SiPM on each side of each fibre (ru_sipmt_top_p, ru_sipmt_bot_p)