# Scintillation Balloon for Neutrinoless Double-Beta Decay Search with Liquid Scintillator Detectors

## TL;DR

This paper proposes a scintillation balloon as an active vessel in liquid scintillator detectors to effectively identify and reject background radioactivity, thereby enhancing the search sensitivity for neutrinoless double-beta decay.

## Contribution

The study introduces a novel scintillation balloon design that enables high-efficiency tagging of radioactive decay sequences, improving background rejection in double-beta decay experiments.

## Key findings

- Achieves 99.7% efficiency in tagging bismuth-polonium decay sequences.
- Enhances sensitivity to neutrinoless double-beta decay by reducing beta-ray background.
- Feasibility demonstrated with KamLAND-type detector setup.

## Abstract

Environmental radioactivity is a dominant background for rare decay search experiments, and it is difficult to completely remove such an impurity from detector vessels. We propose a scintillation balloon as the active vessel of a liquid scintillator in order to identify this undesirable radioactivity. According to our feasibility studies, the scintillation balloon enables the bismuth--polonium sequential decay to be tagged with a 99.7\% efficiency, assuming a KamLAND (Kamioka Liquid scintillator AntiNeutrino Detector)-type liquid scintillator detector. This tagging of sequential decay using alpha-ray from the polonium improves the sensitivity to neutrinoless double-beta decay with rejecting beta-ray background from the bismuth.