Field test around Fukushima Daiichi nuclear power plant site using improved Ce:Gd3(Al,Ga)5O12 scintillator Compton camera mounted on an unmanned helicopter

Yoshiaki Shikaze, Yukiyasu Nishizawa, Yukihisa Sanada, Tatsuo Torii, Jianyong Jiang, Kenji Shimazoe, Hiroyuki Takahashi, Masao Yoshino, Shigeki Ito, Takanori Endo, Kosuke Tsutsumi, Sho Kato, Hiroki Sato, Yoshiyuki Usuki, Shunsuke Kurosawa, Kei Kamada, Akira Yoshikawa

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


An improved light-weight Compton camera exhibiting low power consumption was developed to be mountable on an unmanned helicopter to detect cesium radiation hot spots and confirm the decontamination effect of cesium-affected areas. An increase in the Ce:Gd3(Al,Ga)5O12 scintillator array from 4 × 4 to 8 × 8 and expansion of the interlayer distance enhanced the detection efficiency and angular resolution, respectively. Measurements were performed over the Ukedo riverbed in Namie, Fukushima Prefecture (Japan). The helicopter's flight path and speed were pre-programmed to lines interspaced by 5 and 10 m intervals and 1 m/s, respectively, facilitating measurements over areas of 65 × 60 m2 and 65 × 180 m2 at a height of 10 m for approximately 20 and 30 min, respectively. Results provided accurate ambient dose equivalent rate maps at a height of 1 m with an angular resolution corresponding to a position resolution of approximately 10 m from a height of 10 m. Hovering flights were executed over hot-spot areas for 10–20 min at a height of 5–20 m. Gamma-ray images of these hot spots were obtained using a reconstruction software. Comparison between position-shifted measurement results showed that the angular resolution coincided with that evaluated in the laboratory (approximately 10°).

Original languageEnglish
Pages (from-to)1907-1918
Number of pages12
Journaljournal of nuclear science and technology
Issue number12
Publication statusPublished - 2016 Dec 1


  • Ce:Gd(Al,Ga)O scintillator
  • Compton camera
  • aerial radiation monitoring system
  • ambient dose equivalent rate map
  • gamma-ray image reconstruction
  • unmanned helicopter

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering


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