Characterization studies of silica aerogel for Cherenkov radiator

We can produce highly transparent silica aerogels with high refractive index by using the novel pin-drying method. In this paper, we present characterization studies of aerogels with refractive indices of 1.05 to 1.07 for a Cherenkov radiator. We use the laser Fraunhofer method, an X-ray absorption technique, and a ring imaging Cherenkov detector on a beam test to investigate the uniformity of density (i.e., refractive index) of an aerogel tile. We observed an increase in density at the edge of pin-dried aerogel tiles.