Optical Photon Simulation with Mitsuba3

TL;DR

This paper introduces a pipeline that offloads optical photon propagation from Geant4 to Mitsuba3, significantly accelerating simulations on CPU and GPU, with potential for broader applications.

Contribution

A novel plugin and pipeline enabling efficient optical photon simulation transfer from Geant4 to Mitsuba3, achieving substantial speed-ups on CPU and GPU.

Findings

Photon propagation rate of 2×10^5 photons/sec per CPU thread

Photon propagation rate of 1.2×10^6 photons/sec per GPU

Speed-up of 70 on CPU and 400 on GPU over Geant4

Abstract

Optical photon propagation is an embarrassingly parallel operation, well suited to acceleration on GPU devices. Rendering of images employs similar techniques -- for this reason, a pipeline to offload optical photon propagation from Geant4 to the industry-standard open-source renderer Mitsuba3 has been devised. With the creation of a dedicated plugin for single point multi-source emission, we find a photon propagation rate of $2\times10^{5}$ photons per second per CPU thread using LLVM and $1.2\times10^{6}$ photons per second per GPU using CUDA. This represents a speed-up of 70 on CPU and 400 on GPU over Geant4 and is competitive with other similar applications. The potential for further applications is discussed.