The iTOP detector is a novel Cherenkov detector developed for barrel 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⋅1035cm−2s−1. In order to exploit the high collision rate, Belle II has a trigger frequency 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. The photon arrival times have to be measured with a resolution better than 100 ps to achieve a good pion–kaon separation. 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 in March 2019. The design of the iTOP detector is shown and experience and results from initial operation are discussed together with an outlook on future running conditions.
•New detector type developed for Belle II.•Particle identification via time of propagation.•Data-taking started March 2019.
The Time-Of-Propagation detector is a Cherenkov particle identification detector based on quartz radiator bars for the Belle II experiment at the SuperKEKB e+e−− collider. The purpose of the detector ...is to identify the type of charged hadrons produced in e+e−− collisions, and requires a single photon timing resolution below 100 picoseconds. A novel front-end electronic system was designed, built, and integrated to acquire data from the 8192 microchannel plate photomultiplier tube channels in the detector. Waveform sampling of these analog signals is done by switched-capacitor array application-specific integrated circuits. The processes of triggering, digitization of windows of interest, readout, and data transfer to the Belle II data acquisition system are managed by Xilinx Zynq-7000 programmable system on a chip devices.
The Time-Of-Propagation detector is a Cherenkov particle identification detector based on quartz radiator bars for the Belle II experiment at the SuperKEKB e+e- collider. The focus of the detector is ...to identify the type of charged hadrons produced in e+e- collisions, and requires a single photon timing resolution below 100 picoseconds. A novel front-end electronic system was created, built, and integrated to acquire data from the 8192 microchannel plate photomultiplier tube channels in the detector. Waveform sampling of these analog signals is done by switched-capacitor array application-specific integrated circuits. The processes of triggering, digitization of windows of interest, readout, and data transfer to the Belle II data acquisition system are managed by Xilinx Zynq-7000 programmable system on a chip devices.
The Time-Of-Propagation detector is a Cherenkov particle identification detector based on quartz radiator bars for the Belle II experiment at the SuperKEKB electron-positron collider. The purpose of ...the detector is to identify the type of charged hadrons produced in electron-positron collisions, and requires a single photon timing resolution below 100 picoseconds. A novel front-end electronic system was designed, built, and integrated to acquire data from the 8192 microchannel plate photomultiplier tube channels in the detector. Waveform sampling of these analog signals is done by switched-capacitor array application-specific integrated circuits. The processes of triggering, digitization of windows of interest, readout, and data transfer to the Belle II data acquisition system are managed by Xilinx Zynq-7000 programmable system on a chip devices.
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