Fast Muon Simulation in the JUNO Central Detector

TL;DR

This paper introduces a voxel-based fast simulation method for muon passage in the JUNO detector, significantly reducing computational time while maintaining physics accuracy.

Contribution

It presents a novel voxel-based parameterization technique that accelerates optical photon simulation in large neutrino detectors by a factor of 50.

Findings

Speed-up factor of 50 in optical photon simulation

Comparable physics performance between fast and full simulation

Efficient handling of large-scale muon simulations in JUNO

Abstract

The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose neutrino experiment designed to measure the neutrino mass hierarchy using a central detector (CD), which contains 20 kton liquid scintillator (LS) surrounded by about 17,000 photomultiplier tubes (PMTs). Due to the large fiducial volume and huge number of PMTs, the simulation of a muon particle passing through the CD with the Geant4 toolkit becomes an extremely computation-intensive task. This paper presents a fast simulation implementation using a so-called voxel method: for scintillation photons generated in a certain LS voxel, the PMT's response is produced beforehand with Geant4 and then introduced into the simulation at runtime. This parameterisation method successfully speeds up the most CPU consuming process, the optical photon's propagation in the LS, by a factor of 50. In the paper, the comparison of physics performance between fast and full simulation is also given.