Mar 24, 2026 · Discussion forum for the Geant4 simulation toolkit

Jan 30, 2026 · I would like to share some practical experience on importing CAD geometries into Geant4, as this question comes up regularly and many of the problems are not obvious from the …

Jan 17, 2024 · It turns out I was too quick to open this topic, probably I was a bit more confident as usual due to the fact that multiple people reported this before and the lack of response. I’m now convinced …

Apr 7, 2025 · Please fill out the following information to help in answering your question, and also see tips for posting code snippets. If you don’t provide this information it will take more time to help with …

Aug 8, 2024 · Dear, G4 User I am analysing the detector signal using the Cs-137 source term. I registered ‘RadioactiveDecayPhysics’ in the physics list and here is a snippet of the .mac file that …

Apr 30, 2024 · I attempt to run a simple calorimetry simulation of electrons hitting a detector using G4beamline. For energies under ±25 MeV, it seems as if the physics lists that are designed to …

Jul 17, 2021 · Hi lobis I would like to ask if your problem is solved, I also have the problem of not finding the physical volume when using /gps/pos/confine, I am using parallel geometry to define this physical …

Sep 21, 2023 · Ive got an Xray simulation up and running which looks quite good for my expectations but i still got some weird hits recorded: this for example is a silver target at 40keV im wondering why …

Jul 11, 2023 · There are some problems with reproducing accurate thermal neutron capture gamma ray spectra for (n,gamma) reactions fir some isotopes when using the HP physics. In short, agreement is …

Feb 3, 2021 · Hello, I am trying to generate an initial distribution in the surface of a sphere. I want the particles to be generated only from the first half of a sphere. I am using the following commands in …