Spin coating TPB film on acrylics and measurement of its wavelength shifting efficiency

TL;DR

This paper presents a spin coating technique for applying TPB films on acrylics, measuring their properties and wavelength shifting efficiency to improve detection of VUV scintillation light in neutrino and dark matter experiments.

Contribution

It introduces a novel spin coating method for TPB films, providing detailed fabrication, characterization, and efficiency measurements for detector applications.

Findings

Successful fabrication of TPB films with controlled thickness and roughness

Reemission spectrum centered around 425 nm confirming wavelength shifting

Quantified wavelength shifting efficiency of the spin coated TPB films

Abstract

Scintillation light from liquid noble gas in a neutrino or dark matter experiment lies typically within the vacuum ultraviolet (VUV) region and might be strongly absorbed by surrounding materials such as light guides or photomultiplier. Tetraphenyl butadiene (TPB) is a fluorescent material and acts as a wavelength shifter (WLS) which can turn the UV light to the visible light around a peak wavelength of 425 nm, enabling the light signals to be detected easily for physics study. Compared with a traditional TPB coating method using vapor deposition, we propose an alternative technique with a spin coating procedure in order to facilitate the development of neutrino and dark matter detectors. This article introduces how to fabricate the TPB film on acrylics using the spin coating method, reports measurement of sample film thickness and roughness, shows the reemission spectrum, and quantifies the wavelength shifting efficiency (WLSE).