Measurements of angle-resolved reflectivity of PTFE in liquid xenon with IBEX

Authors :: L. Hagaman
Ethan Bernard
L. Tvrznikova
G. D. Orebi Gann
L. Rudd
Daniel McKinsey
S. Kravitz
M. Sakai
Richard J. Smith
Source :: European Physical Journal, European Physical Journal C, vol 80, iss 3, European Physical Journal C: Particles and Fields, Vol 80, Iss 3, Pp 1-20 (2020)
Publication Year :: 2020
Publisher :: Springer Science and Business Media LLC, 2020.
Abstract: Liquid xenon particle detectors rely on excellent light collection efficiency for their performance. This depends on the high reflectivity of polytetrafluoroethylene (PTFE) at the xenon scintillation wavelength of 178 nm, but the angular dependence of this reflectivity is not well-understood. IBEX is designed to directly measure the angular distribution of xenon scintillation light reflected off PTFE in liquid xenon. These measurements are fully described by a microphysical reflectivity model with few free parameters. Dependence on PTFE type, surface finish, xenon pressure, and wavelength of incident light is explored. Total internal reflection is observed, which results in the dominance of specular over diffuse reflection and a reflectivity near 100% for high angles of incidence.<br />21 pages, 10 figures

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