Improvement of Geant4 Neutron-HP package: from methodology to evaluated nuclear data library

Abstract

An accurate description of interactions between thermal neutrons (below 4 eV) and materials is key to simulate the transport of neutrons in a wide range of applications such as criticality-safety, reactor physics, compact accelerator-driven neutron sources, radiological shielding or nuclear instrumentation, just to name a few. While the Monte Carlo transport code Geant4 was initially developed to simulate particle physics experiments, its use has spread to neutronics applications, requiring evaluated cross-sections for neutrons and gammas between 0 and 20 MeV (the so-called neutron High Precision -HP-package), as well as a proper offline or on-the-flight treatment of these cross-sections. In this paper we will point out limitations affecting Geant4 (version 10.07.p01) thermal neutron treatment and associated nuclear data libraries, by using comparisons with the reference Monte Carlo neutron transport code TRIPOLI-4 ® , version 11, and we will present the results of various modifications of the Geant4 neutron-HP package, required to overcome these limitations. Also, in order to broaden the support of nuclear data libraries compatible with Geant4, a nuclear processing tool has been developed and validated allowing the use of the code together with ENDF-BVIII.0 and JEFF-3.3 libraries for example. These changes should be taken into account in an upcoming Geant4 release.

Neutron availability in the Complementary Experiments Hall of the IFMIF-DONES facility

“…More recently, it has been benchmarked for cold moderators with Tripoli-4 ® [13], a transport Monte Carlo code developed at CEA for reactor physics with depletion, criticality and safety. The benchmark showed a perfect agreement between the two codes [10].…”

“…Simulations are based on Geant4.10.7 [9] using the TOU-CANS (TOolkit for a Unified Compact Accelerator Neutron Sources design) toolkit [10] and MCNP6.2 (Monte Carlo N-Particle Transport Code System Version 6.2) [11]. TOUCANS is a modular code using Geant4 C++ libraries.…”

First observation of isolated nuclear recoils following neutron capture for dark matter calibration

“…In the Geant4 simulation, high-precision electromagnetic physics and neutron physics were used [39,40]. Although newer models of Geant4 (after Geant4.10.5 ) use an upgraded coherent γ-nucleus scattering [41], our simulation uses the older EPDL model [42].…”