29 July 2018 to 4 August 2018
Russian Academy of Sciences
Europe/Moscow timezone

Silica aerogel radiator for the Belle II ARICH system

31 Jul 2018, 10:55
30m
Russian Academy of Sciences

Russian Academy of Sciences

Leninsky Prospekt, 32а Moscow 119071 Russian Federation
Board: 24
poster presentation Technological aspects and applications of Cherenkov detectors Poster Session

Speaker

Makoto Tabata (Chiba University)

Description

The Aerogel Ring-Imaging Cherenkov detector (ARICH) was developed to provide a particle identification in the forward endcap of Belle II detector at a SuperKEKB electron–positron collider at the High Energy Accelerator Research Organization (KEK), Japan. It is used to identify charged $\pi $ and K mesons at momenta between 0.5 and 4.0 GeV/c. The ARICH system is a proximity-focusing RICH counter with an expansion length of 20 cm that uses silica aerogels as radiators and hybrid avalanche photo-detectors as position-sensitive photo-sensors, which was installed in the Belle II spectrometer in late 2017. The design objective is a $\pi $/K separation capability exceeding 4$\sigma $ at a momentum of 4 GeV/c.
To detect more photons without degrading the Cherenkov angle resolution, we introduced a double layer aerogel radiator in a novel focusing configuration. It consists of 2 layers of 2 cm thick aerogel tiles with different refractive indices of 1.045 and 1.055. It is important to reduce the number of the aerogel tiles used to cover the large radiator area (~3.3 m$^2$) because particles cannot be clearly identified in these gaps. Therefore, large, crack-free aerogel tiles are preferred. Installing the tiles onto the module by trimming them with a water-jet cutter and avoiding optical degradation of the aerogels via moisture adsorption during long-term experiments should ultimately result in highly hydrophobic conditions.
Approximately 450 large-area (18 $\times $ 18 $\times $ 2 cm) aerogel tiles were manufactured, and their optical characteristics (refractive index and transmission length) were confirmed to meet the ARICH design requirements. Each tile was cut into wedge shapes using a water-jet cutter to fit the cylindrical support structure. A total of 248 aerogel tiles were successfully installed in the 124 segmented containers of the support structure. Here, results from the development of the dual-layer aerogel radiator module for the Belle II ARICH system are presented.

Primary author

Makoto Tabata (Chiba University)

Co-authors

Ichiro Adachi (High Energy Accelerator Research Organization (KEK), Graduate University of Advanced Science (SOKENDAI)) Leonid Burmsistrov (Laboratoire de Laccelerateur Lineaire (LAL)) Francois Le Diberder (Laboratoire de Laccelerateur Lineaire (LAL)) Shiori Kakimoto (Tokyo Metropolitan University) Hidekazu Kakuno (Tokyo Metropolitan University) Hideyuki Kawai (Chiba University) Takeo Kawasaki (Kitasato University) Haruki Kindo (Graduate University of Advanced Science (SOKENDAI)) Tomoyuki Konno (Kitasato University) Samo Korpar (University of Maribor, Jožef Stefan Institute) Peter Križan (University of Ljubljana, Jožef Stefan Institute) Tetsuro Kumita (Tokyo Metropolitan University) Yun-Tsung Lai (High Energy Accelerator Research Organization (KEK)) Masahiro Machida (Tokyo University of Science) Manca Mrvar (Jožef Stefan Institute) Shohei Nishida (High Energy Accelerator Research Organization (KEK), Graduate University of Advanced Science (SOKENDAI)) Kouta Noguchi (Tokyo Metropolitan University) Kazuya Ogawa (Niigata University) Satoru Ogawa (Toho University) Rok Pestotnik (Jožef Stefan Institute) Luka Šantelj (Hubert Curien Multi-disciplinary Institute (IPHC)) Takayuki Sumiyoshi (Tokyo Metropolitan University) Sachi Tamechika (Tokyo Metropolitan University) Masanobu Yonenaga (Tokyo Metropolitan University) Morihito Yoshizawa (Niigata University) Yosuke Yusa (Niigata University)

Presentation Materials

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