After the Fukushima Dai‐ichi Nuclear Power Plant accident in March 2011, contamination of mulberry-leaf tea with over 100Bq kg－1137Cs was found. We therefore investigated 137Cs distribution in mulberry trees(Morus alba) and soil in Nihonmatsu City from 2012. As a result, mulberry leaves near the end of branches(0 - 30cm), which are usually used as edible leaves, were shown to contain higher 137Cs concentration than the others. Trunk showed highest 137Cs concentration among the plant parts of mulberry investigated, while root 137Cs concentration was relatively low. Autoradiographic studies for leaf, bark and cross-sectional trunk suggest that radioactive substances were deposited onto bark and leaf radioactive contamination could be due to translocation of 137Cs from trunk. Spray application of 0.5% KH2PO4 solution onto trunk surface significantly reduced 137Cs concentration in edible leaves emerged about one month after the application. However, the effect was limited and insufficient to solve the problem of radioactive contamination in edible mulberry leaves.
Commercially available instant coffee, Nescafe Excella, contained the radionuclide 40K. From the instant coffee, sixteen coffee-block radiation sources were successfully fabricated with sufficiently low production dependences. The coffee-block radiation sources were examined their suitability for a radiation protection course. Although a part of radiation counts(cpm) obtained with 1minute measurement were largely deviated, those determined by 5 minute measurements and five times of 1 minute measurement were less deviated, enabling better comprehension of the three cardinal principles of radiation protection.
The detection efficiency to obtain radon concentration in ground water by γ-ray spectrometry was determined using a standard volume source in stead of previous 226Ra standard source. Radon concentration of ground water in a 100mL Teflon vial was determined from the γ-ray measurement of the 352keV γ ray emitted from 214Pb on the assumption that radon and its progenies were in a radioactive equilibrium in a closed vial. The 352keV γ-ray counting efficiency for a 100mL Teflon vial was determined based on the detection efficiency of Ge detector from a standard volume source in a U8 container. The detection limit in this method was 8Bq/L. The radon concentrations in ground water from 6 locations were agreed well with previous method.
The MUSE facility, located in the Materials and Life Science Facility(MLF), is a building integrated to include both neutron and muon science programs. For Phase 1, we installed a superconducting decay/surface channel(D-Line) with a modest-acceptance(about 40 msr) pion injector, extracting either surface muons(μ＋) or decay muons(μ＋/μ－) rate of up to 120MeV/c. In addition to Phase1, we installed a surface muon channel with a modest-acceptance(about 50 msr)(U-Line) mainly for the study of nano-science converting to Ultra Slow Muons(50eV - 30keV). At present, we are now constructing the third muon beamline(S-Line)dedicated to the materials science and the fourth beamline(H-Line) for the fundamental physics.
Inelastic neutron scattering can measure the protein thermal fluctuations under the physiological aqueous environment, especially it is powerful to observe the low-energy protein dynamics in THz region, which are revealed theoretically to be coupled with solvations. Neutron enables the selective observation of protein and hydration water by deuteration. The complementary analysis with molecular dynamics simulation is also effective for the study of protein hydration. Some examples of the application toward the understanding of molecular basis of protein functions will be introduced.