title: Measurement of residual 60Co activity induced by atomic-bomb neutrons in Nagasaki and background contribution by environmental neutrons.
abstract: Residual 60Co activity in five steel samples induced by neutrons from the Nagasaki atomic bomb has been measured within about 1000 m from the hypocenter. The chemical separation of cobalt and nickel from steel samples was performed, and cobalt-enriched samples were prepared for all samples. Gamma-ray measurements were carried out with a low-background well-type germanium detector. The gamma-ray spectra for five samples were compared with the spectrum of a control sample to ensure that the observed 60Co was actually induced by A-bomb neutrons. The activation of cobalt by environmental neutrons was also investigated. It has been shown that the present 60Co data are consistent with earlier Hashizume's data.
authors.affiliation: Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima 739-8527, Japan. shizuma@hiroshima-u.ac.jp
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Shizuma
authors.forename: Satoru
authors.initials: S
authors.lastname: Endo
authors.forename: Masaharu
authors.initials: M
authors.lastname: Hoshi
authors.forename: Jun
authors.initials: J
authors.lastname: Takada
authors.forename: Kazuo
authors.initials: K
authors.lastname: Iwatani
authors.forename: Hiromi
authors.initials: H
authors.lastname: Hasai
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Oka
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Shimazaki
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Okumura
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Fujita
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Watanabe
authors.forename: Tetsuji
authors.initials: T
authors.lastname: Imanaka
mesh_terms: D001417:Background Radiation; D003036:Cobalt Isotopes / Q000528:radiation effects*; D003037:Cobalt Radioisotopes / Q000032:analysis* / Q000302:isolation & purification; D003252:Construction Materials / Q000032:analysis; D003359:Cosmic Radiation; D005720:Gamma Rays; D006207:Half-Life; D006785:Hospitals, University; D006798:Housing; D007564:Japan; D009502:Neutrons; D009689:Nuclear Warfare; D011848:Radioactive Pollutants / Q000032:analysis* / Q000302:isolation & purification; D011874:Radiometry; D012574:Schools; D013232:Steel / Q000737:chemistry
chemical_list: D003036:Cobalt Isotopes; D003037:Cobalt Radioisotopes; D011848:Radioactive Pollutants; D013232:Steel