Undoped CsI calorimeter for the K0L → π0vv̄ experiment at KEK-PS

M. Doroshenko, K. Abe, J. K. Ahn, Y. Akune, V. Baranov, Y. Fujioka, Y. B. Hsiung, T. Ikei, T. Inagaki, S. Ishibashi, H. Ishii, T. Iwata, S. Kobayashi, S. Komatsu, T. K. Komatsubara, A. Kurilin, E. Kuzmin, A. Lednev, H. S. Lee, S. Y. LeeG. Y. Lim, T. Matsumura, T. Mizuhashi, A. Moisseenko, T. Morimoto, T. Nakano, N. Nishi, J. Nix, T. Nomura, T. Oba, H. Okuno, K. Omata, G. N. Perdue, S. Perov, S. Podolsky, S. Porokhovoy, K. Sakashita, N. Sasao, H. Sato, T. Sato, M. Sekimoto, T. Shinkawa, Y. Sugaya, A. Sugiyama, T. Sumida, Y. Tajima, Z. Tsamalaidze, T. Tsukamoto, Y. Wah, H. Watanabe, M. Yamaga, T. Yamanaka, H. Y. Yoshida, Y. Yoshimura

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


An electromagnetic calorimeter consisting of 576 undoped CsI crystals has been used to search for the KL0→π0νν̄ decay at the KEK 12-GeV proton synchrotron (E391a). The calorimeter is placed in a vacuum of lower than 10-1 Pa. Special energy and timing calibrations have been performed. The energy calibration started from a check of the linearity for nine sample crystals using an electron beam. Then, after mounting all crystals in the E391a detector, we made an in situ calibration of the energy by using cosmic ray and punch-through muons. The gain constants obtained from both muons agree with each other with an accuracy of 2% (σ). They were further refined by using γγ samples from π0's produced off an aluminum plate (5-mm thick) hit by neutral beam particles. Using the final gain constants, we obtained a KL0 mass resolution of 4.3 MeV/c2 (σ) for the KL0→π0π0π0 decay. Also, using the timing constants measured for cosmic rays, we obtained a resolution of 0.51 ns (σ) for the timing difference among six γ's in the KL0→π0π0π0 decay.

Original languageEnglish
Pages (from-to)278-295
Number of pages18
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number1-2
Publication statusPublished - 2005 Jun 11
Externally publishedYes

Bibliographical note

Funding Information:
The authors express their sincere thanks to the operating staff of the 12-GeV KEK proton synchrotron and the beam channel group for providing us a good quality neutral beam to the E391a detector. This work has been partly supported by a Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology in Japan and by the Japan Society for the Promotion of Science (JSPS). One of us (M.D.) acknowledges the receipt of the Japanese Government Scholarship (Monbukagakusho; MEXT) during this work.


  • CsI calorimeter
  • Energy calibration
  • K decay
  • Timing calibration

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


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