Pulse shape discrimination of photons and neutrons in the energy range of 0.1 – 2 GeV with the KOTO un-doped CsI calorimeter

Y. Sugiyama, J. K. Ahn, S. Banno, B. Beckford, M. Campbell, S. H. Chen, J. Comfort, Y. T. Duh, T. Hineno, Y. B. Hsiung, M. Hutcheson, E. Iwai, I. Kamiji, N. Kawasaki, E. J. Kim, J. L. Kim, Y. J. Kim, J. W. Ko, T. K. Komatsubara, A. S. KurilinJ. W. Lee, S. K. Lee, G. Y. Lim, C. Lin, Q. Lin, Y. Luo, J. Ma, Y. Maeda, T. Masuda, T. Matsumura, D. Mcfarland, R. Murayama, D. Naito, K. Nakagiri, Y. Nakaya, H. Nanjo, T. Nomura, Y. Odani, J. C. Redeker, Y. D. Ri, N. Sasao, K. Sato, S. Seki, T. Shimogawa, T. Shinkawa, S. Shinohara, K. Shiomi, S. Su, S. Suzuki, Y. Tajima, G. Takahashi, Y. Takashima, M. Tecchio, M. Togawa, Y. C. Tung, Y. W. Wah, H. Watanabe, N. Whallon, J. K. Woo, J. Xu, T. Yamanaka, Y. Yanagida, H. Y. Yoshida, H. Yoshimoto

Research output: Contribution to journalArticlepeer-review


A pulse shape difference between photons and neutrons was observed in the output signals of scintillation light from the un-doped CsI calorimeter of the KOTO experiment for the KL→π0νν̄ decay. We developed a discrimination method to reject neutrons and to accept photons in the deposited energy range from 0.1 to 2 GeV. The method rejects 67% of neutron-induced single hadronic clusters and 86% of neutron-induced two-cluster events while keeping more than 90% of photon-induced single electromagnetic clusters and two-photon events.

Original languageEnglish
Article number164825
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Publication statusPublished - Jan 21 2021
Externally publishedYes


  • Calorimeter
  • CsI crystal
  • Pulse shape discrimination
  • Rare kaon decay
  • Waveform analysis

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


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