Presentation

Presentation of STARucn

• Presentation of STARucn
  • Introduction
  • Structure of a simulation

Introduction

STARucn is a ROOT based simulation software dedicated to ultra-cold neutron transport. It has been primarily developed at Grenoble's LPSC as a tool for the GRANIT experiment

It makes extensive use of ROOT’s geometry package, graphics (ROOT and OpenGL) and powerful outputs such as histograms and trees.

For standard user, STARucn is designed as an easy to configure software using ascii scripts (« parameter files »), for configuration and geometry without any need to recompile the code

The code is also modular: the main steps of the simulation are dealt through plug-ins classes which use polymorphism and heritage (virtual methods). A set of default plugins is provided, but advanced user can also develop their own plugins adding extra functionalities without touching the main code structure.

Structure of a simulation

The main structure of the code is the following:

• Read the main parameter file
• Build the geometry (geometry input file)
• Build the 4 processors plug-ins : Generator, Propagator, Interaction and Output (specific config file(s) for each)
• NEUTRON GENERATION LOOP
  • Generate the initial position and speed of the neutro : Generator plug-in
  • PROPAGATION LOOP
    • Propagate neutron to the next interface: Propagator plug-in
    • Decide the interaction of the neutron in the volume and at the surface: Interaction plug-in
    • Save output for this step: Output plug-in
  • Save final info for this neutron: Output plug-in
• Save outputs and end of process

The propagation loop ends when the neutron is « killed », which means it is either absorbed, decayed, out of geometry or made too many bounces (safety).

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