Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

URANOS -- a novel voxel engine Neutron Transport Monte-Carlo Simulation

Markus Köhli, Martin Schrön, Steffen Zacharias, Ulrich Schmidt

TL;DR

URANOS addresses the need for a fast, accessible neutron transport simulator tailored to detector development and environmental studies. It uses a voxel-based geometry and a ray-casting Monte Carlo approach, with cross sections from ENDF/B and JENDL, and a compact physics model including elastic, inelastic, absorption, and evaporation processes. For higher energies, it adopts an effective cascade model and supports detector-like scoring through a full-domain flux layer or virtual detectors. The tool is implemented in C++ with ROOT and QT, provides built-in source spectra, and is available openly on GitLab with documentation and examples; comparisons with MCNP indicate good agreement, making it a practical alternative for instrument design and environmental neutron transport studies.

Abstract

URANOS is a newly developed 3D neutron transport Monte-Carlo code from thermal to fast energy domains. It was originally developed for the CASCADE detector. The purpose of this simulation program is to provide a fast computational workflow and an intuitive graphical user interface (GUI) for small to medium-sized projects. It features a ray-casting algorithm based on a voxel engine. The simulation domain is defined layerwise, whereas the geometry is extruded from a pixel matrix of materials, identified by specific numbers. Input files are a stack of pictures, all other settings, including the configuration of predefined sources, can be adjusted via the GUI. The scattering kernel features the treatment of elastic and inelastic collisions, absorption and absorption-like processes like evaporation. Cross sections, energy distributions and angular distributions are taken from evaluated data bases. In order to simulate boron-lined detectors it also models the charged particle transport following the conversion by computing the energy loss in the boron and its consecutive layer. The electron track is then projected onto a readout unit by longitudinal and transversal diffusion. URANOS is freely available and can be used to simulate the response function of boron-lined or epithermal neutron detectors, small-scale laboratory setups and especially transport studies of cosmic-ray induced environmental neutrons. It offers an easy accessibility and comparably simple interface capable of handling complex geometries. URANOS therefore offers possibilities to understand and simulate the neutron environment at instruments, which would otherwise require extensive modeling and training on dedicated packages.

URANOS -- a novel voxel engine Neutron Transport Monte-Carlo Simulation

TL;DR

URANOS addresses the need for a fast, accessible neutron transport simulator tailored to detector development and environmental studies. It uses a voxel-based geometry and a ray-casting Monte Carlo approach, with cross sections from ENDF/B and JENDL, and a compact physics model including elastic, inelastic, absorption, and evaporation processes. For higher energies, it adopts an effective cascade model and supports detector-like scoring through a full-domain flux layer or virtual detectors. The tool is implemented in C++ with ROOT and QT, provides built-in source spectra, and is available openly on GitLab with documentation and examples; comparisons with MCNP indicate good agreement, making it a practical alternative for instrument design and environmental neutron transport studies.

Abstract

URANOS is a newly developed 3D neutron transport Monte-Carlo code from thermal to fast energy domains. It was originally developed for the CASCADE detector. The purpose of this simulation program is to provide a fast computational workflow and an intuitive graphical user interface (GUI) for small to medium-sized projects. It features a ray-casting algorithm based on a voxel engine. The simulation domain is defined layerwise, whereas the geometry is extruded from a pixel matrix of materials, identified by specific numbers. Input files are a stack of pictures, all other settings, including the configuration of predefined sources, can be adjusted via the GUI. The scattering kernel features the treatment of elastic and inelastic collisions, absorption and absorption-like processes like evaporation. Cross sections, energy distributions and angular distributions are taken from evaluated data bases. In order to simulate boron-lined detectors it also models the charged particle transport following the conversion by computing the energy loss in the boron and its consecutive layer. The electron track is then projected onto a readout unit by longitudinal and transversal diffusion. URANOS is freely available and can be used to simulate the response function of boron-lined or epithermal neutron detectors, small-scale laboratory setups and especially transport studies of cosmic-ray induced environmental neutrons. It offers an easy accessibility and comparably simple interface capable of handling complex geometries. URANOS therefore offers possibilities to understand and simulate the neutron environment at instruments, which would otherwise require extensive modeling and training on dedicated packages.
Paper Structure (4 sections, 3 figures)

This paper contains 4 sections, 3 figures.

Table of Contents

  1. Introduction
  2. Concept and Interface
  3. Usage and workflow
  4. Conclusion

Figures (3)

  • Figure 1: URANOS main user interface for the calculation of a source inside a polyethylene box with (1) simulation control bar with status information, (2) general configuration tabs, (3) 'Live View' tabs for user feedback about the current run, (4) global environmental settings, (5) geometry stack with layers defined by voxels, (6) source definition (7), neutron energy spectrum above the ground layer and (8) cross section view of the neutron flux within the domain in the detector layer.
  • Figure 2: URANOS example for the calculation of a neutron flux distribution within a laboratory with a $^{252}$Cf source: (a) stacked input geometry with grayscale codes for different materials, (b) three-dimensional extrusion of the layers and (c) result of the calculation for different energy windows from the MeV range over fast and epithermal neutrons to the thermal regime.
  • Figure 3: URANOS example for the calculation of response functions of Bonner Spheres: (a) part of the stacked input layer geometry, (b) cross section of the neutron flux through the spheres (top row) or integrated over the entire volume (lower row) for different energy ranges and (c) result of the response function calculation and comparison to Mares3He.