Light Response of Poly(ethylene 2,6-napthalate) to Neutrons

TL;DR

This study measures the neutron response of Poly(ethylene 2,6-naphthalate) (PEN), demonstrating its potential as a low-background scintillation material for rare-event physics applications.

Contribution

It provides the first comprehensive measurement of PEN's quenching factor using multiple neutron sources, establishing key scintillation parameters for its use in physics experiments.

Findings

Birk's factor determined as 0.12 ± 0.01 mm MeV^{-1}

Scintillation efficiency found to be 1.31 ± 0.09 MeV_{ee} MeV^{-1}

PEN shows promise for large-scale low-background detectors.

Abstract

There is increasing necessity for low background active materials as ton-scale, rare-event and cryogenic detectors are developed. Poly(ethylene-2,6-naphthalate) (PEN) has been considered for these applications because of its robust structural characteristics, and its scintillation light in the blue wavelength region. Radioluminescent properties of PEN have been measured to aid in the evaluation of this material. In this article we present a measurement of PEN's quenching factor using three different neutron sources; neutrons emitted from spontaneous fission in $^{252}$Cf, neutrons generated from a DD generator, and neutrons emitted from the $^{13}$C($\alpha$,n)$^{16}$O and the $^{7}$Li(p,n)$^{7}$Be nuclear reactions. The fission source used time-of-flight to determine the neutron energy, and the neutron energy from the nuclear reactions was defined using thin targets and reaction kinematics. The Birk's factor and scintillation efficiency were found to be $kB = 0.12 \pm 0.01$ mm MeV$^{-1}$ and $S = 1.31\pm0.09$ MeV$_{ee}$ MeV$^{-1}$ from a simultaneous analysis of the data obtained from the three different sources. With these parameters, it is possible to evaluate PEN as a viable material for large-scale, low background physics experiments.