PALM -- Precision Attenuation Length Measurement in Liquid Scintillators

TL;DR

The paper introduces PALM, a new optical spectrometer designed to measure the attenuation length of liquids used in large-scale neutrino detectors, ensuring precise optical property measurements crucial for experiment success.

Contribution

Development of PALM, a novel optical spectrometer capable of in-situ, high-precision attenuation length measurements of liquids up to 100 meters in the 400-1000 nm range.

Findings

PALM successfully measures attenuation lengths up to 100 m.

The setup demonstrates high reproducibility at 430 nm and 500 nm.

PALM's optical system enables in-situ monitoring during measurements.

Abstract

Future neutrino experiments at low energies such as JUNO or THEIA will use large volume homogeneous liquid scintillator detectors. The optical attenuation length of the liquid is of uttermost importance for the successful realization of these experiments. At TU Munich a new optical spectrometer (Precision Attenuation Length Measurement (PALM)) has been set up in order to measure the light attenuation of liquids which can be used for these types of experiments up to around 100 m in the wavelength region between 400 nm and 1000 nm. The setup features an optical imaging system with a long focal length, which allows for in-situ monitoring of the beam stability during the measurement. The setup capability as well as the reproducibility of its results has been demonstrated at two different wavelengths of 430 nm and 500 nm.