Detailed investigation on the Geant4 simulation of alpha particles in liquid scintillator detector
Abstract
Purpose: Alpha particles from 214Po, 212Po, and 210Po are increasingly used to calibrate large liquid scintillator detectors, but Geant4 simulations of their energy deposition require detailed validation. Methods: We simulate alpha particles in a 4 m cube of LAB-based liquid scintillator with Geant4 11.4.2 and apply Birks quenching per step. We study step-size, production-threshold, Birks-constant, and electromagnetic-model dependence, and use Geant4-DNA to examine keV-scale electron track structure. Results: Delta-electron-associated fluctuations dominate the simulated response. Across the tested explicit-delta settings, the variance of the quenched-response contribution from secondary tracks is 1.01--1.12 times the total variance; a negative primary--secondary covariance reduces the total. The simulated quenching-curve shape is compatible with SNO+ data within current uncertainties, with χ2/ndf≃0.14--$0.17$ for kB=0.007--$0.010$ g cm−2 MeV−1. Geant4-DNA gives strong electron-track curvature, with tortuosity decreasing from about 6 at 200 eV to 1.6 at 10 keV. Conclusion: Delta-electron fluctuations are the dominant contribution to the intrinsic resolution in the tested configurations. The production threshold has a larger effect than the electromagnetic model: Penelope and Livermore agree within about 3% in L/E, whereas Standard gives higher L/E, especially at low thresholds.
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BibTeX
@misc{xu2026detailed,
title = {{Detailed investigation on the Geant4 simulation of alpha particles in liquid scintillator detector}},
author = {Shiwen Xu and Shubing Liu and Zeyuan Yu},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23793},
eprint = {2609.23793},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23793},
}
RIS
TY - UNPB
TI - Detailed investigation on the Geant4 simulation of alpha particles in liquid scintillator detector
AU - Shiwen Xu
AU - Shubing Liu
AU - Zeyuan Yu
PY - 2026
DA - 2026/09/20
PB - arXiv
DO - 10.48550/arxiv.2609.23793
UR - https://arxiv.org/abs/2609.23793
AB - Purpose: Alpha particles from ^214Po, ^212Po, and ^210Po are increasingly used to calibrate large liquid scintillator detectors, but Geant4 simulations of their energy deposition require detailed validation. Methods: We simulate alpha particles in a 4 m cube of LAB-based liquid scintillator with Geant4 11.4.2 and apply Birks quenching per step. We study step-size, production-threshold, Birks-constant, and electromagnetic-model dependence, and use Geant4-DNA to examine keV-scale electron track structure. Results: Delta-electron-associated fluctuations dominate the simulated response. Across the tested explicit-delta settings, the variance of the quenched-response contribution from secondary tracks is 1.01--1.12 times the total variance; a negative primary--secondary covariance reduces the total. The simulated quenching-curve shape is compatible with SNO+ data within current uncertainties, with χ^2/ndf≃0.14--$0.17$ for k_B=0.007--$0.010$ g cm^−2 MeV^−1. Geant4-DNA gives strong electron-track curvature, with tortuosity decreasing from about 6 at 200 eV to 1.6 at 10 keV. Conclusion: Delta-electron fluctuations are the dominant contribution to the intrinsic resolution in the tested configurations. The production threshold has a larger effect than the electromagnetic model: Penelope and Livermore agree within about 3% in L/E, whereas Standard gives higher L/E, especially at low thresholds.
ER -