Polyethylene naphthalate film as a wavelength shifter in liquid argon detectors

TL;DR

This paper investigates polyethylene naphthalate (PEN) as a new wavelength shifter for liquid argon detectors, showing it could replace traditional materials like TPB due to similar fluorescence properties and potential advantages for large-scale applications.

Contribution

The study presents evidence that PEN is a viable alternative to TPB for wavelength shifting in liquid argon detectors, with potential benefits for scaling up detector technology.

Findings

PEN has comparable fluorescence yield to TPB.

PEN's timing characteristics are similar to TPB.

PEN offers advantages for large-scale detector deployment.

Abstract

Liquid argon-based scintillation detectors are important for dark matter searches and neutrino physics. Argon scintillation light is in the vacuum ultraviolet region, making it hard to be detected by conventional means. Polyethylene naphthalate (PEN), an optically transparent thermoplastic polyester commercially available as large area sheets or rolls, is proposed as an alternative wavelength shifter to the commonly-used tetraphenyl butadiene (TPB). By combining the existing literature data and spectrometer measurements relative to TPB, we conclude that the fluorescence yield and timing of both materials may be very close. The evidence collected suggests that PEN is a suitable replacement for TPB in liquid argon neutrino detectors, and is also a promising candidate for dark matter detectors. Advantages of PEN are discussed in the context of scaling-up existing technologies to the next generation of very large ktonne-scale detectors. Its simplicity has a potential to facilitate such scale-ups, revolutionizing the field.