On peculiarities of the annealing process for highly transparent silica based aerogel tiles manufactured in Novosibirsk

A collaboration between the Boreskov Institute of Catalysis and the Budker Institute of Nuclear Physics (BINP) has been producing silica aerogel blocks for Cherenkov detectors since 1986. Novosibirsk-manufactured aerogel is used in several experiments: KEDR and SND (BINP, Russia), LHCb (CERN, Switzerland), AMS-02 (ISS), and CLAS12 RICH (Jefferson Lab, USA). This work describes key advancements in the production technology for large-scale aerogel radiators used in Ring-Imaging CHerenkov (RICH) detectors. Annealing is one of the major stages of the highly transparent aerogel production in Novosibirsk. Its procedure was investigated in detail and optimized to improve the yield of aerogel tiles useful for the RICH detectors. The optical and mechanical parameters of the largest silica aerogel samples produced in Novosibirsk using the new annealing procedure are presented.