Measurement of the fluorescence quantum yield of bis-MSB

TL;DR

This paper measures the fluorescence quantum yield of bis-MSB, a key liquid scintillator component, providing essential data for optimizing detector performance and improving Monte Carlo simulations.

Contribution

First measurement of bis-MSB fluorescence quantum yield up to 430 nm, crucial for accurate scintillator modeling and detector optimization.

Findings

Quantum yield of bis-MSB is 0.926±0.053 at 350 nm excitation.

Provides data for better Monte Carlo simulation inputs.

Enhances understanding of photon re-emission in liquid scintillators.

Abstract

The fluorescence quantum yield of bis-MSB, a widely used liquid scintillator wavelength shifter, was measured to study the photon absorption and re-emission processes in liquid scintillator. The re-emission process affects the photoelectron yield and distribution, especially in a large liquid scintillator detector, thus must be understood to optimize the liquid scintillator for good energy resolution and to precisely simulate the detector with Monte Carlo. In this study, solutions of different bis-MSB concentration were prepared for absorption and fluorescence emission measurements to cover a broad range of wavelengths. Harmane was used as a standard reference to obtain the absolution fluorescence quantum yield. For the first time we measured the fluorescence quantum yield of bis-MSB up to 430 nm as inputs required by Monte Carlo simulation, which is 0.926$\pm$0.053 at $\lambda_{\rm ex}$ = 350 nm.