# Quenching Measurements and Modeling of a Boron-Loaded Organic Liquid Scintillator

## TL;DR

This paper presents measurements of neutron-induced proton recoils in a boron-loaded organic liquid scintillator, compares them to quenching models, and identifies a modified Birks' model that best describes the data, aiding neutron detection accuracy.

## Contribution

The study provides the first detailed measurements of nuclear recoil quenching in boron-loaded scintillators and identifies the most accurate model for predicting scintillation response.

## Key findings

- Modified Birks' model fits data well
- Recoil energies ranged from 57 to 467 keV
- Results improve neutron tagging efficiency

## Abstract

Organic liquid scintillators are used in a wide variety of applications in experimental nuclear and particle physics. Boron-loaded scintillators are particularly useful for detecting neutron captures, due to the high thermal neutron capture cross section of $^{10}$B. These scintillators are commonly used in neutron detectors, including the DarkSide-50 neutron veto, where the neutron may produce a signal when it scatters off protons in the scintillator or when it captures on $^{10}$B. Reconstructing the energy of these recoils is complicated by scintillation quenching. Understanding how nuclear recoils are quenched in these scintillators is an important and difficult problem. In this article, we present a set of measurements of neutron-induced proton recoils in a boron-loaded organic liquid scintillator at recoil energies ranging from 57--467 keV, and we compare these measurements to predictions from different quenching models. We find that a modified Birks' model whose denominator is quadratic in $dE/dx$ best describes the measurements, with $\chi^2$/NDF$=1.6$. This result will help model nuclear recoil scintillation in similar detectors and can be used to improve their neutron tagging efficiency.