Reflectance of Polytetrafluoroethylene (PTFE) for Xenon Scintillation Light

TL;DR

This study measures the reflectance properties of various PTFE samples at 175 nm, crucial for optimizing xenon-based particle detectors used in dark matter and neutrino experiments.

Contribution

It provides detailed reflectance data for different PTFE types at VUV wavelengths, including angular distribution and modeling, filling a knowledge gap for detector design.

Findings

Reflectance of PTFE ranges from 47% to 66% at 175 nm.

Different manufacturing processes affect PTFE reflectance.

Data includes angular distribution and physical modeling of reflections.

Abstract

Gaseous and liquid xenon particle detectors are being used in a number of applications including dark matter search and neutrino-less double beta decay experiments. Polytetrafluoroethylene (PTFE) is often used in these detectors both as electrical insulator and as a light reflector to improve the efficiency of detection of scintillation photons. However, xenon emits in the vacuum ultraviolet wavelength region (175 nm) where the reflecting properties of PTFE are not sufficiently known. In this work we report on measurements of PTFE reflectance, including its angular distribution, for the xenon scintillation light. Various samples of PTFE, manufactured by different processes (extruded, expanded, skived and pressed) have been studied. The data were interpreted with a physical model comprising both specular and diffuse reflections. The reflectance obtained for these samples ranges from about 47% to 66% for VUV light. Fluoropolymers, namely ETFE, FEP and PFA were also measured.