A Scintillator Purification System for the Borexino Solar Neutrino Detector

TL;DR

This paper details the design, construction, and commissioning of a purification system that significantly reduces backgrounds in the Borexino solar neutrino detector by purifying large quantities of liquid scintillator using multiple techniques.

Contribution

It introduces a comprehensive purification system combining distillation, water extraction, gas stripping, and filtration for large-scale liquid scintillator purification.

Findings

Achieved unprecedented low background levels in the detector

Successfully purified 278 tons of scintillator and 889 tons of buffer shielding

Demonstrated effective system design and leak-tightness

Abstract

Purification of the 278 tons of liquid scintillator and 889 tons of buffer shielding for the Borexino solar neutrino detector was performed with a system that combined distillation, water extraction, gas stripping and filtration. The purification of the scintillator achieved unprecedented low backgrounds for the large scale liquid scintillation detector. This paper describes the principles of operation, design, construction and commissioning of the purification system, and reviews the requirements and methods to achieve system cleanliness and leak-tightness.