The Imaging Time-of-Propagation Detector at Belle II
Abstract
We report on the construction, operation, and performance of the Time-of-Propagation detector with imaging used for the Belle II experiment running at the Super-KEKB collider. This detector is located in the central barrel region and uses Cherenkov light to provide particle identification among hadrons. The Cherenkov light is radiated in highly polished bars of synthetic fused silica (quartz) and transported to the ends of the bars via total internal reflection. One bar end is instrumented with finely segmented micro-channel-plate photomultiplier tubes to record the light, while the other end has a mirror attached to reflect the photons back to the instrumented end. Both the propagation times and hit positions of the Cherenkov photons are measured; these depend on the Cherenkov angle and together provide good discrimination among charged pions, kaons, and protons with momenta up to around 4 GeV/. To date, the detector has been used to record and analyze almost 600 fb of Belle II data.
Keywords
Cite
@article{arxiv.2504.19090,
title = {The Imaging Time-of-Propagation Detector at Belle II},
author = {Hulya Atmacan and Matt Belhorn and Yinghui Guan and Longke Li and Bilas Pal and Saurabh Sandilya and Alan Schwartz and Boqun Wang and Shun Watanuki and Matthew Andrew and Matthew Barrett and Martin Bessner and Thomas Browder and J. Bynes and J. Cercillieux and Shawn Dubey and Oskar Hartbrich and Chris Ketter and Brian Kirby and Shahab Kohani and D. Kotchetkov and Luca Macchiarulo and B. Macek and Kurtis Nishimura and H. Purwar and Z. Sang and V. Shebalin and S. Tripathy and Gary Varner and K. Yoshihara and T. Kohriki and X. Wang and S. P. Maharana and V. S. Vismaya and Gerard Visser and Alessandro Gaz and Stefano Lacaprara and R. Stroili and Ezio Torassa and Roberto Mussa and Umberto Tamponi and Peter Krizan and Samo Korpar and Tara Nanut and A. Novosel and Marko Petric and L. Rizzuto and Marko Staric and Lucien Cremaldi and David Sanders and Y. Adachi and Y. Arita and D. Furumura and S. Hara and T. Hayakawa and S. Hirose and Y. Horii and Toru Iijima and Kenji Inami and Y. Ito and Y. Kato and N. Kiribe and R. Koga and K. Kojima and A. Maeda and Y. Maeda and K. Maehara and R. Maeshima and Kodai Matsuoka and G. Muroyama and T. Nakano and R. Okubo and R. Okuto and R. Omori and S. Senga and K. Suzuki and H. Takeichi and N. Tsuzuki and T. Yonekura and R. Conrad and James Fast and Brian Fulsom and Jan Strube and Lynn Wood and I. Danko and T. Gu and N. Herring and N. K. Nisar and S. Roffe and Vladimir Savinov and E. Wang and Vishal Bhardwaj and Alyssa Loos and Milind Purohit and Carl Rosenfeld},
journal= {arXiv preprint arXiv:2504.19090},
year = {2025}
}
Comments
46 pages, 48 figures, 4 tables. Version 2: as published in Nuclear Instruments and Methods in Physics Research A