nanoVMC: The minimalist Virtual Monte Carlo example

Purpose

Provide a minimal, yet flexible example for a VMC Simulation application:

• Geometries are defined outside in a ROOT macro and loaded via TGeoManager
• Multiple sensitive detectors are supported
• Energy depositions are recorded in histograms for each sensitive detector
• The primary generator can be changed in the macro, no recompilation necessary

Constituents

Compiled Code:

• MCApplication: The main application, handles all setup and execution tasks, derived from TVirtualMCApplication.
• MCStack: The list of particles in the event, derived from TVirtualMCStack. For unknown and incomprehensible reasons, each VMC app has to implement (read: copy & paste) this for oneself.
• Sensitive Detector: Keeps track of the energy depositions in each sensitive volume.

Macros:

• createGeo*.C: Creates a root geometry to be loaded in the VMC app. Note that each sensitive volume should be defined here by name.
• run_g4.C: Runs the VMC Simulation using Geant4. All libraries should be auto-loaded if their location is in the environment variable LD_LIBRARY_PATH.
• g4Config.C: Basic configuration for Geant4.
• do.sh: Demonstrates example usage.

Installation:

Prerequisites:

Geant4_VMC needs to be correctly installed with all dependencies. I recommend simply installing all of FairSoft. All of ROOT, Geant4, VMC, etc. are extremely sensitive to environment variables. You need to make sure everything is set up properly. Use export LD_LIBRARY_PATH=... liberally and edit the CMakeFile.txt if necessary.

Clone and build:

(set environment variables first!)
git clone https://github.com/janmayer/nanoVMC.git
cd nanoVMC
mkdir build
cd build
cmake ..
make

Run ./do.sh in macros.

Acknowledgements:

Very loosely based on the examples provided with geant4_VMC by I. Hrivnacova (IPN, Orsay). Copy & Pasted the MCStack. Inheriting GPL.