Large-area silica aerogel for use as Cherenkov radiators with high refractive index, developed by supercritical carbon dioxide drying

Abstract

This study presents the development of large-area (18 × 18 × 2 cm 3 ), high refractive index (n ∼1.05) hydrophobic silica aerogel tiles for use as Cherenkov radiators. These transparent aerogel tiles will be installed in a Cherenkov detector for the next-generation accelerator-based particle physics experiment Belle II, to be performed at the High Energy Accelerator Research Organization (KEK) in Japan. Cracking has been eliminated from the prototype aerogel tiles by improving the supercritical carbon dioxide (scCO 2 ) extraction procedure when drying the wet gel tiles. Finally, a method of mass-producing aerogel tiles for the actual detector was established. It was confirmed that the experimentally manufactured aerogel tiles meet the required optical and hydrophobic characteristics and have a uniform tile density.

Kinetics of Supercritical Drying of Gels

“…The cycling goes on until the gel is dried. There are some reported studies in the literature where the drying of a single sample is continued for almost one week [11,25,26]. The experimental variables such as temperature, pressure, and flowrate are often set quite arbitrarily.…”

Gradual hydrophobization of silica aerogel for controlled drug release

“…2,3 The aerogels' highly versatile synthesis procedures allow tailoring of the material's properties, such as the bulk density, 4 pore size, 5 and surface chemistry. 6 This exibility makes aerogels a sought-aer material for a great variety of applications, including thermal insulators, 7 absorbents, 8 oilwater separators, 9 llers, 10 electrode materials, 11 catalysts, 12 tissue-scaffolds, 13 stents, 14 enzyme supports, 15 Cherenkov radiators, 16 optical devices 17 and cosmic dust collectors. 18 Among the many tunable characters, one critical feature is the hydrophobicity of the aerogel surface.…”

Effects of reaction parameters on the preparation of P4VP/SiO2 composite aerogel via supercritical CO2 drying

“…The boundary from liquid to gas disappears to prevent the Δ p , leading to the formation of a transparent aerogel with structurally complete 3D network structure with low density. Van Bormml et al successfully obtained a SiO 2 aerogel with excellent performance under low temperature condition via the supercritical drying method.…”