Efficient determination of HPGe {\gamma}-ray efficiencies at high energies with ready-to-use simulation software

TL;DR

This paper presents G4Horus, a user-friendly Geant4 software tool for accurately simulating high-energy gamma-ray efficiencies of HPGe detectors, addressing challenges in geometry modeling and discrepancies in efficiency measurements.

Contribution

Introduction of G4Horus, a modular, ready-to-use Geant4 application that simplifies high-energy gamma-ray efficiency simulations for HPGe detectors with minimal setup.

Findings

G4Horus effectively models detector efficiencies up to 10 MeV.

Discrepancies in older detectors can be corrected with dead region adjustments.

Open-source availability encourages community adaptation.

Abstract

The full-energy-peak efficiency of HPGe detectors at $\gamma$-ray energies around 10 MeV is not easily accessible with experimental methods. Monte-Carlo simulations with Geant4 can provide these efficiencies. G4Horus is a ready-to-use Geant4 application for the HORUS HPGe-detector array. Users can configure the modular parts to match their experiment with minimal knowledge of the simulation software and limited time commitment. In our case, knowing and implementing the geometry with high precision is the biggest challenge. To implement the different target chambers, we transform the existing CAD models to Geant4 geometry with CADMesh. We also found a large discrepancy between experimental and simulated efficiency for some older HPGe detectors, which could be remedied by introducing a large dead region around the inner core. This project is open source and available from https://github.com/janmayer/G4Horus We invite everyone to adapt the project or adopt parts of the code for other projects.