Author/Authors :
Tabata، نويسنده , , Makoto and Adachi، نويسنده , , Ichiro and Hamada، نويسنده , , Nao and Hara، نويسنده , , Koji and Iijima، نويسنده , , Toru and Iwata، نويسنده , , Shuichi and Kakuno، نويسنده , , Hidekazu and Kawai، نويسنده , , Hideyuki and Korpar، نويسنده , , Samo and Kri?an، نويسنده , , Peter and Kumita، نويسنده , , Tetsuro and Nishida، نويسنده , , Shohei and Ogawa، نويسنده , , Satoru and Pestotnik، نويسنده , , Rok and ?antelj، نويسنده , , Luka and Seljak، نويسنده , , Andrej and Sumiyoshi، نويسنده , , Takayuki and Tahirovi?، نويسنده , , Elvedin and Yoshida، نويسنده , , Keisuke and Yusa، نويسنده , , Yosuke، نويسنده ,
Abstract :
This paper presents recent progress in the development and mass production of large-area hydrophobic silica aerogels for use as radiators in the aerogel-based ring-imaging Cherenkov (A-RICH) counter, which will be installed in the forward end cap of the Belle II detector. The proximity-focusing A-RICH system is especially designed to identify charged kaons and pions. The refractive index of the installed aerogel Cherenkov radiators is approximately 1.05, and we aim for a separation capability exceeding 4σ at momenta up to 4 GeV/c. Large-area aerogel tiles (over 18×18×2 cm3) were first fabricated in test productions by pin drying in addition to conventional methods. We proposed to fill the large end-cap region (area 3.5 m2) with 124 water-jet-trimmed fan-shaped dual-layer-focusing aerogel combinations of different refractive indices (1.045 and 1.055). Guided by the test production results, we decided to manufacture aerogels by the conventional method and are currently proceeding with mass production. In an electron beam test undertaken at the DESY, we confirmed that the K/π separation capability of a prototype A-RICH counter exceeded 4σ at 4 GeV/c.
Keywords :
Silica aerogel , Belle II , Cherenkov radiator , rich , Pin drying
