The Borexino detector at the Laboratori Nazionali del Gran Sasso

TL;DR

Borexino is an underground liquid scintillator detector designed for real-time low-energy solar neutrino detection, with detailed descriptions of its structure, systems, and performance, demonstrating its effectiveness in neutrino spectroscopy.

Contribution

This paper provides a comprehensive overview of Borexino's detector design, systems, and performance, highlighting its capabilities for low-energy solar neutrino measurement.

Findings

Detector performance meets or exceeds design expectations

Effective neutrino-electron scattering detection in ultra-pure scintillator

Successful real-time measurement of sub MeV solar neutrinos

Abstract

Borexino, a large volume detector for low energy neutrino spectroscopy, is currently running underground at the Laboratori Nazionali del Gran Sasso, Italy. The main goal of the experiment is the real-time measurement of sub MeV solar neutrinos, and particularly of the mono energetic (862 keV) Be7 electron capture neutrinos, via neutrino-electron scattering in an ultra-pure liquid scintillator. This paper is mostly devoted to the description of the detector structure, the photomultipliers, the electronics, and the trigger and calibration systems. The real performance of the detector, which always meets, and sometimes exceeds, design expectations, is also shown. Some important aspects of the Borexino project, i.e. the fluid handling plants, the purification techniques and the filling procedures, are not covered in this paper and are, or will be, published elsewhere (see Introduction and Bibliography).