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

Abstract

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 arXiv:1511.07725v1 [physics.ins-det]

In-situ measurement of the scintillation light attenuation in liquid argon in the Gerda experiment

“…Comparing our result to other measurements of the attenuation length of scintillation light in LAr [3,20,21] the obtained value is much smaller. The result in [20] of about 50 cm is in the same order of magnitude like measured in this work.…”

“…However in other measurements very pure LAr was taken initially and doped with impurities in order to measure the attenuation dependent on the impurity composition. These measurements with the purest LAr samples result in 1.10 m [21] and in 30 − 1790 m [3]. On the contrary the LAr in the GERDA cryostat is not exposed to any purification plant and dwells in the cryostat already before the start of Phase I of GERDA in 2011.…”

Scintillation light detection in the 6-m drift length ProtoDUNE Dual Phase liquid argon TPC

“…The amplitude decreases 35% when adding 5.8 ppm of Xe and 1.7 ppm of N 2 with respect to pure LAr for both trigger modes, being unaffected by the N 2 addition. This reduction is due to the absorption of the 127-nm photons by the Xe atoms as reported in [19]. Whilst a 15% decrease of the fast component (S1 amplitude) for the CRT-trigger data is expected when adding N 2 according to [20], we observe the fast component remains constant for the two N 2 injections.…”

Attenuation measurements of vacuum ultraviolet light in liquid argon revisited

“…We already measured the transmission of systematically xenon-doped liquid argon and the results are published in ref. [14]. Only a wavelength-resolved measuring principle allows to identify impurities like xenon (or others) in nominally pure argon.…”

“…Dependening on concentration and composition impurities affect both the emission as well as the transmission (see refs. [5,14]). Measuring the attenuation length in a wavelength-integrated way (e.g.…”