A Study of the Fluorescence Response of Tetraphenyl-butadiene

TL;DR

This study investigates the stability and batch variations of TPB, a fluorescent material used in particle detectors, revealing yellowing and degradation effects under prolonged light exposure.

Contribution

It provides new insights into the stability issues and batch-to-batch variability of TPB used in liquid-argon detectors.

Findings

99% pure TPB exhibits yellowing under light exposure

Degradation of TPB emission peak occurs with extended light exposure

Batch-to-batch variations affect TPB fluorescence response

Abstract

Tetraphenyl-butadiene (TPB) is a widely used fluorescent wavelength-shifter. A common application is in liquid-argon-based particle detectors, where scintillation light is produced in the UV at 128 nm. In liquid argon experiments, TPB is often employed to shift the scintillation light to the visible range in order to allow detection via standard photomultiplier tubes. This paper presents studies on the stability of TPB with time under exposure to light. We also examine batch-to-batch variations. We compare scintillation-grade TPB to 99% pure TPB response. In the 99% pure samples, we report a yellowing effect, and full degradation of the TPB emission-peak, upon extended exposure to light.