Mainz 2014 – scientific programme

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T: Fachverband Teilchenphysik

T 32: Dunkle Materie 2

T 32.6: Talk

Monday, March 24, 2014, 18:00–18:15, P11

Attenuation of Vacuum Ultraviolet Light in Liquid Argon — •Alexander Neumeier¹, Thomas Dandl¹, Thomas Heindl¹, Martin Hofmann¹, Lothar Oberauer¹, Walter Potzel¹, Stefan Schönert¹, Andreas Ulrich¹, and Jochen Wieser² — ¹Physik-Department E12/E15, TU-München, James-Franck-Str. 1, 85748 Garching — ²Excitech GmbH, Branterei 33, 26419 Schortens

Liquid noble gases, argon and xenon, in particular, are excellent high density scintillator media with a high scintillation efficiency. Detectors use the scintillation light emitted by the noble gases excited by a traversing charged particle. In large-volume detectors it is important to understand the attenuation of the scintillation light in the medium to determine the detector response. We will present wavelength resolved absorption spectra of vacuum ultraviolet (VUV) light in liquid argon (A. Neumeier et al., Eur. Phys. J. C (2012) 72:2190). The light emitted by a broad-band VUV light source (D2-lamp) was sent through 58mm of liquid argon and subsequently analyzed with an evacuated VUV monochromator. The results show a strongly reduced transmission due to water and xenon impurities. The latter can not be removed by conventional noble gas purification techniques. Only a combined purification of fractional distillation and conventional rare gas purification leads to an attenuation length of the order of meters.

This research was supported by the DFG cluster of excellence 'Origin and Structure of the Universe' and the Maier-Leibnitz-Laboratorium München.