Abstract
Abstract
The use of wavelength-shifting coatings is of primary interest in the area of liquified
noble gases detectors. Argon and xenon are used as active medium in the neutrino physics and dark
matter experiments, because charged particles crossing the noble liquid volume produce excitation
and ionization followed by recombination and both the processes lead to the emission of VUV light.
Noble liquid scintillation light emitted in the VUV range needs to be converted to be detected by
conventional photosensors. Wavelength-shifting materials, such as TetraPhenyl-Butadiene and
p-TerPhenyl, are used for this conversion to the visible range. The wavelength-shifters are
particularly important in the case of large area detectors since only a fraction of the surface
can be instrumented. To this purpose dedicated set-ups have been built and specific techniques
have been adopted to produce and characterize very uniform wavelength-shifting coatings on highly
reflecting material substrates, optical filters and optical guides. Some type of the facilities
used to this task, with particular attention to the vacuum deposition systems, will be described,
operations for production of the coatings will be reported, methods for the characterization of
the samples will be briefly presented.