Optical properties of low background PEN structural components for the LEGEND-200 experiment

TL;DR

This paper evaluates the optical properties of low-background PEN plastic scintillator components, produced via injection compression molding, for use as active detector holders in the LEGEND-200 neutrinoless double beta decay experiment, assessing their light output and veto efficiency.

Contribution

It provides the first detailed measurement of optical and surface properties of radio-pure PEN components for low-background physics applications.

Findings

Measured emission spectrum, time constant, attenuation, and absorption length of PEN components.

Characterized surface roughness and light yield of the detector holders.

Estimated the self-vetoing efficiency of the PEN-based detector components.

Abstract

Polyethylene Naphthalate (PEN) plastic scintillator has been identified as potential self-vetoing structural material in low-background physics experiments. Scintillating components have been produced radio-pure from PEN using injection compression molding technology. These low-background PEN components will be used as active holders to mount the Germanium detectors in the \legend-$200$ neutrinoless double beta decay experiment. In this paper we present the measurement of the optical properties of these PEN components. Thus, the emission spectrum, time constant, attenuation and bulk absorption length as well as light output and light yield are reported. In addition, the surface of these PEN components has been characterized and an estimation of the surface roughness is presented. Moreover, the light output of the final \legend-$200$ detector holders has been measured and is reported. These measurements were used to estimate the self-vetoing efficiency of these holders.