15 research outputs found
Index of refraction, Rayleigh scattering length, and Sellmeier coefficients in solid and liquid argon and xenon
Large liquid argon detectors have become widely used in low rate experiments,
including dark matter and neutrino research. However, the optical properties of
liquid argon are not well understood at the large scales relevant for current
and near-future detectors.The index of refraction of liquid argon at the scin-
tillation wavelength has not been measured, and current Rayleigh scattering
length calculations disagree with measurements. Furthermore, the Rayleigh
scattering length and index of refraction of solid argon and solid xenon at
their scintillation wavelengths have not been previously measured or
calculated. We introduce a new calculation using existing data in liquid and
solid argon and xenon to extrapolate the optical properties at the
scintillation wavelengths using the Sellmeier dispersion relationship.Comment: 11 pages, 4 figure
Absorption of Scintillation Light in a 100 Liquid Xenon Ray Detector and Expected Detector Performance
An 800L liquid xenon scintillation ray detector is being developed
for the MEG experiment which will search for decay
at the Paul Scherrer Institut. Absorption of scintillation light of xenon by
impurities might possibly limit the performance of such a detector. We used a
100L prototype with an active volume of 372x372x496 mm to study the
scintillation light absorption. We have developed a method to evaluate the
light absorption, separately from elastic scattering of light, by measuring
cosmic rays and sources. By using a suitable purification technique,
an absorption length longer than 100 cm has been achieved. The effects of the
light absorption on the energy resolution are estimated by Monte Carlo
simulation.Comment: 18 pages, 10 figures (eps). Submitted to Nucl. Instr. and Meth.
VUV absorbing vapours in n-perfluorocarbons
Albrecht E, Baum G, Bellunato T, et al. VUV absorbing vapours in n-perfluorocarbons. Nucl.Instrum.Meth. A. 2003;510(3):262-272.The optical transparency, of perfluorocarbons used as Cherenkov media is of prime importance to many Ring Imaging Cherenkov detectors. We will in this paper show that the main photon absorbers in these fluids are hydrocarbons with double or triple bonds. We will moreover discuss a process which can eliminate these pollutants and restore the intrinsic excellent optical transparency of these fluids in the VUV range. (C) 2003 Elsevier B.V. All rights reserved