Feb 18 – 22, 2019
Vienna University of Technology
Europe/Vienna timezone

Performance of the Belle II imaging Time-Of-Propagation (iTOP) detector in first collisions

Feb 22, 2019, 10:15 AM


Talk Plenary 4


Martin Bessner (Deutsches Elektronen-Synchrotron (DE))


The iTOP detector is a novel Cherenkov detector developed for particle identification at Belle II, an upgrade of the previous Belle experiment at KEK. The SuperKEKB accelerator, an upgrade of KEKB, collides electrons and positrons with a design luminosity of 8*10^(35)/(cm^2 s). In order to exploit the high collision rate Belle II has a trigger rate of up to 30 kHz.
The iTOP detector uses quartz bars as source of Cherenkov photons. The photons are reflected inside the bars until they hit photomultipliers at one end. The spatial distribution and precise arrival times of the detected photons are used to reconstruct the Cherenkov angle. To achieve a good pion-kaon separation the photon arrival times have to be measured with a resolution better than 100 ps. Microchannel plate photomultipliers together with dedicated high-speed electronics for 2.7 GSa/s waveform sampling are used to achieve this timing resolution. The iTOP detector consists of 16 modules with 512 channels each, in total the detector has 8192 channels.
First collisions were recorded in Spring 2018. A phase of physics operation with a ramp up to full luminosity starts March 2019. In this talk the design of the iTOP detector will be shown and experience and results from initial operation will be discussed together with an outlook on future running conditions.

Primary author

Martin Bessner (Deutsches Elektronen-Synchrotron (DE))


Alessandro Gaz (KMI, Nagoya University) Gary Varner (University of Hawaii) Dr Hulya Atmacan (University of Cincinnati) Kenji Inami (Nagoya university) Kodai Matsuoka (Nagoya University) Kurtis Nishimura (University of Hawai) Oskar Hartbrich (University of Hawaii) Toru Iijima (Nagoya University) Yosuke Maeda (Nagoya University)

Presentation materials