Production and validation of scintillating structural components from low-background Poly(ethylene naphthalate)

TL;DR

This paper presents the production and validation of radiopure, scintillating Poly(ethylene naphthalate) (PEN) components for use in low-background physics experiments, demonstrating their suitability for cryogenic detector mounting.

Contribution

It introduces a method to produce and validate radiopure, transparent PEN components as active structural elements for rare event detection experiments.

Findings

PEN scintillates in the blue region and maintains mechanical properties at cryogenic temperatures.

Produced PEN plates are radiopure and suitable for mounting germanium detectors.

First application in LEGEND-200 demonstrates practical use in cryogenic environments.

Abstract

Poly Ethylene Naphthalate (PEN) is an industrial polymer plastic which is investigated as a low background, transparent, scintillating and wavelength shifting structural material. PEN scintillates in the blue region and has excellent mechanical properties both at room and cryogenic temperatures. Thus, it is an ideal candidate for active structural components in experiments for the search of rare events like neutrinoless double-beta decay or dark matter recoils. Such optically active structures improve the identification and rejection efficiency of background events, like this improving the sensitivity of experiments. This paper reports on the production of radiopure and transparent PEN plates These structures can be used to mount germanium detectors operating in cryogenic liquids (LAr, LN). Thus, as first application PEN holders will be used to mount the Ge detectors in the LEGEND-200 experiment. The whole process from cleaning the raw material to testing the PEN active components under final operational conditions is reported.