GUIMesh: A tool to import STEP geometries into Geant4 via GDML

Abstract

Detailed radiation analysis of instruments flown in space is critical to ensure mission safety, often requiring the use of state-of-the-art particle transport simulation tools. Geant4 is one of the most powerful toolkits to simulate the interaction and the passage of particles through matter. This framework however, is not prepared to receive Standard for The Exchange of Product data (STEP) files, the most versatile Computer-Aided Design (CAD) format, as inputs requiring previous conversion to other formats. This, especially when the instruments have complex shapes, and/or a large number of volumes may lead to loss of detail and under or overestimation of the quantities under study. Though several solutions have been proposed to import complex geometries into Geant4, so far, only commercial options are available. In this paper we present a new tool, GUIMesh, that embeds FreeCAD libraries, an open-source CAD editor, to tessellate volumes, and convert them to Geometry Description Markup Language (GDML), a Geant4 readable format, in a straightforward way. Several degrees of freedom are given to the user regarding the mesh and choice of material. Different geometries were tested for p material definition, geometry and navigation errors, successfully validating the method used.

Efficient determination of HPGe γ-ray efficiencies at high energies with ready-to-use simulation software

“…A conversion can either be performed with plugins in the CAD program, a standalone software, or as a dependency in the Geant4 application itself. For example, plugins have once been developed for FreeCAD [32,33] and CATIA [34]. Notable standalone projects are cad-to-geant4-converter [35], STEP-to-ROOT [36], SW2GDMLconverter [37], and McCad-Salome [29].…”

Study on Detector Geometry Transformation and Visualization in Unity

“…The method is realized with the help of two software tools, FreeCAD [8] and Pixyz Studio [9]. FreeCAD is a common software for engineering drawings, with a workbench that supports importing GDML files [18]. Based on FreeCAD and GDML workbench [19], it is possible to convert GDML to STEP, a standard format in the CAD field.…”

Design and Characterization of a Compact Radiation Monitor for Space Rockets

“…The results are shown in Figure 8 and the number of counts fall as expected with increasing since the intensity of the radiation depends on 𝑟 2 . The test also simulated using Geant4 taking in to account the air density in Ankara, Turkey at the time as 𝜌 𝑎𝑖𝑟 = 1.08 𝑘𝑔/𝑚 3 [16,17]. The maximum range of an alpha particle from Am-241 in silicon is calculated as 28µm using SRIM [18].…”