Attenuation of vacuum ultraviolet light in pure and xenon-doped liquid argon —An approach to an assignment of the near-infrared emission from the mixture
1 Physik-Department E15, Technische Universität München - James-Franck-Straße 1, 85748 Garching, Germany
2 Physik-Department E12, Technische Universität München - James-Franck-Straße 1, 85748 Garching, Germany
Received: 6 May 2015
Accepted: 3 July 2015
Results of transmission experiments of vacuum ultraviolet light through a 11.6 cm long cell filled with pure and xenon-doped liquid argon are described. Pure liquid argon shows no attenuation down to the experimental short-wavelength cut-off at 118 nm. Based on a conservative approach, a lower limit of 1.10 m for the attenuation length of its own scintillation light could be derived. Adding xenon to liquid argon at concentrations on the order of parts per million leads to strong xenon-related absorption features which are used for a tentative assignment of the recently found near-infrared emission observed in electron-beam excited liquid argon-xenon mixtures. Two of the three absorption features can be explained by perturbed xenon transitions and the third one by a trapped exciton (Wannier-Mott) impurity state. A calibration curve connecting the equivalent width of the absorption line at 140 nm with xenon concentration is provided.
PACS: 29.40.Mc – Scintillation detectors / 33.20.Ni – Vacuum ultraviolet spectra / 61.25.Bi – Liquid noble gases
© EPLA, 2015