Speaker
Description
The use of wavelength-shifting coatings are of primary interest in the area of liquified noble gases detectors, namely, argon and xenon used as active medium in the neutrino
physics and dark matter experiments.
In fact, 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 (WLS) materials, such as TetraPhenyl-Butadiene and P-Terphenyl, are especially used for this conversion in the visible range. In particular, the wavelength-shifters are very 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 and/or optical filters.
Some of the facilities used to this task will be described, operations for production of the coatings will be reported and methods for the characteriztion of the samples will be presented. Improvement on the techniques will be also discussed.
