Scintillation of thin tetraphenyl butadiene films under alpha particle excitation

TL;DR

This study investigates the scintillation properties of thin TPB films under alpha particle excitation to better understand surface alpha backgrounds in dark matter detection, revealing photon yield and decay characteristics.

Contribution

It provides new measurements of photon yield and decay times of vacuum-deposited thin TPB films under alpha excitation, aiding background modeling in dark matter experiments.

Findings

Thin TPB films emit approximately 882 photons per MeV under alpha excitation.

The scintillation decay has two components with lifetimes of about 11 ns and 275 ns.

Results help improve understanding of surface alpha backgrounds in dark matter searches.

Abstract

The alpha induced scintillation of the wavelength shifter 1,1,4,4-tetraphenyl-1,3-butadiene (TPB) was studied to improve the understanding of possible surface alpha backgrounds in the DEAP dark matter search experiment. We found that vacuum deposited thin TPB films emit 882 +/-210 photons per MeV under alpha particle excitation. The scintillation pulse shape consists of a double exponential decay with lifetimes of 11 +/-5 ns and 275 +/-10ns.