Silica aerogel Cherenkov counter for the KEK B-factory experiment

Abstract

Low-refractive-index silica aerogel is a convenient radiator for threshold-type Cherenkov counters, which are used for particle identification in high-energy physics experiments. For the BELLE detector at the KEK B-Factory we have produced about 2 m3 of hydrophobic silica aerogels of n=1.01–1.03 using a new production method. The particle identification capability of the aerogel Cherenkov counters was tested and 3σ pion/proton separation has been achieved at 3.5 GeV/c. Radiation hardness of the aerogels was confirmed up to 9.8 Mrad. The Aerogel Cherenkov counter system (ACC) was successfully installed in the BELLE just before this conference.