Results from R&D of Cherenkov detectors at Novosibirsk

Our group produces silica aerogels with refractive indices of 1.006-1.13 with good optical transparency. The particle identification systems for the KEDR and the SND detectors based on threshold aerogel counters are described. Cosmic test results for the SND counters are presented. The possibility of employing a RICH with a sodium fluoride crystal radiator for π/K separation up to 5GeV/c momentum is explored. The combined NaF-aerogel radiator is proposed to decrease the minimum working momentum of the RICH below the Cherenkov threshold in aerogel.