Study of the loss of Xenon Scintillation in Xenon-Trimethylamine Mixtures

TL;DR

This study examines whether TMA molecules can shift xenon VUV scintillation light to longer wavelengths and assesses the loss of scintillation in Xe-TMA mixtures, finding minimal reemission and quantifying absorption properties.

Contribution

It provides experimental evidence that TMA does not significantly reemit xenon scintillation light and measures the absorption coefficient of TMA for xenon VUV light.

Findings

No reemission observed above 0.3% detection limit.

Absorption coefficient of TMA for xenon VUV light is 0.43+/-0.03 cm^-1.Torr^-1.

TMA has minimal impact on xenon scintillation in the tested mixtures.

Abstract

This work investigates the capability of TMA ((CH3)3N) molecules to shift the wavelength of Xe VUV emission (160-188 nm) to a longer, more manageable, wavelength (260-350 nm). Light emitted from a Xe lamp was passed through a gas chamber filled with Xe-TMA mixtures at 800 Torr and detected with a photomultiplier tube. Using bandpass filters in the proper transmission ranges, no reemitted light was observed experimentally. Considering the detection limit of the experimental system, if reemission by TMA molecules occurs, it is below 0.3% of the scintillation absorbed in the 160-188 nm range. An absorption coefficient value for xenon VUV light by TMA of 0.43+/-0.03 cm-1.Torr-1 was also obtained. These results can be especially important for experiments considering TMA as a molecular additive to Xe in large volume optical time projection chambers.