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and 90 bombarded with 120-GeV protonsIwamoto, Yosuke; Sanami, Toshiya*; Kajimoto, Tsuyoshi*; Shigyo, Nobuhiro*; Hagiwara, Masayuki*; Lee, H. S.*; Soha, A.*; Ramberg, E.*; Coleman, R.*; Jensen, D.*; et al.
Progress in Nuclear Science and Technology (Internet), 3, p.65 - 68, 2012/10
Neutron energy spectra at 15 and 90 produced from carbon, aluminum, copper and tungsten targets bombarded with 120-GeV protons were measured at Fermilab Test Beam Facility (FTBF) for the validation of simulation codes. The target thicknesses were 60 cm for graphite, 50 cm for aluminum, 20, 40, and 60 cm for copper and 10 cm for tungsten, respectively. The neutron time-of-flight measurements were performed using an NE213 organic liquid scintillator at 5.2 m for 90 and 8.0 m for 15 measuring from the center of the target to the surface of the detector. The raw signals (waveforms) obtained from photomultiplier tubes were recorded using the 10 bit digitizer (Agilent-acqiris DC282) with 0.5 ns sampling and 500 ns duration. To compare the experimental results, Monte Carlo calculations with the PHITS, MARS and FLUKA codes were performed. It was found that these calculated results underestimate the experimental results in the whole energy range.
Kimura, Masanori; Kinase, Sakae; Takahara, Shogo; Homma, Toshimitsu
Progress in Nuclear Science and Technology (Internet), 3, p.19 - 24, 2012/10
The dose received by the public was assessed for one month since the Fukushima Daiichi Nuclear Power Plant accident onset to reconstruct and predict external and internal doses to the public at an area using the radiation monitoring data provided by regulatory authorities. The cumulative doses were estimated by fitting the exponential model, with the decay of nuclides (
I, 
Cs + 
Cs) considered, to the measurement data. The external doses were evaluated by supplementing the measurement data with the estimates. In addition, the internal doses by inhalation and ingestion of radioiodine I were evaluated using the concentration of airborne effluents and the tap water. Consequently, the total dose for the public was found to be less than 20 mSv. The averted dose by restrictions on the ingestion of the tap water was also discussed.
Kinase, Sakae; Kimura, Masanori; Takahara, Shogo; Homma, Toshimitsu
Progress in Nuclear Science and Technology (Internet), 3, p.69 - 71, 2012/10
Takahara, Shogo; Kimura, Masanori; Kinase, Sakae; Ishikawa, Jun; Suyama, Kenya; Hosoyamada, Ryuji; Homma, Toshimitsu
Progress in Nuclear Science and Technology (Internet), 3, p.25 - 29, 2012/10
Dose assessment is one of the important issues to make decisions in contaminated areas resulting from the Fukushima Daiichi Nuclear Power Plant accident. The doses to inhabitants of contaminated areas should be assessed prospectively and retrospectively taking into account the impact from various exposure pathways. The external exposure from deposited radioactive materials of short-lived and long-lived is one of the most important pathways. In the present study, the radionuclide compositions have been evaluated by source term analysis taking into account 54 radionuclides. This analysis consists in evaluating the inventory and the fraction of the radionuclides that were released into the atmosphere. On the assumption that dose rate may be decreased due to the radioactive decay as well as weathering effects, we have assessed the dose for future and past at the contaminated areas. The assessed values are almost consistent with the measured ones during the first month.
