Characterization of the TruSense S310 Laser Range System for Contact-less Measurement of Liquid Levels in Large-Volume Neutrino Detectors

TL;DR

This paper evaluates the TruSense S310 laser range system for non-contact liquid level measurement in neutrino detectors, demonstrating its precision, stability, and compatibility with detector operations.

Contribution

It provides a detailed characterization of the S310 system, including laboratory tests and integration insights for large neutrino detectors like JUNO.

Findings

Short-term precision of ±5 mm achieved

System remains operational during PMT activity

Suitable for long-term stability in detector environments

Abstract

Neutrino experiments often use large volumes of water, organic scintillators or noble liquids as active detection material. Due to the large hydrostatic and buoyancy forces involved, precise knowledge of the liquid levels inside the detector tank are mandatory. Here we present the main characteristics of the TruSense S310 Laser Range System. Level measurements can be performed without direct contact to the liquid and through a gas-proof acrylic window, thus preserving the strict radiopurity and chemical requirements of the target liquid. We report the results of a suit of laboratory experiments for short-term precision tests ($\pm$5\,mm) and long-term stability studies. Moreover, we demonstrate that the infrared laser can be used while standard bi-alkali PMTs are operational. We discuss the mechanical layout and integration of the system in the OSIRIS pre-detector that will monitor the radiopurity of the liquid scintillator for the large-volume neutrino experiment JUNO.