Polarization dependence of soft X-ray absorption spectroscopy on the heavy fermion superconductor CeNiGe

Fujiwara, Hidenori*; Nakatani, Yasuhiro*; Aratani, Hidekazu*; Kanai-Nakata, Yuina*; Yamagami, Kohei*; Hamamoto, Satoru*; Kiss, Takayuki*; Sekiyama, Akira*; Tanaka, Arata*; Ebihara, Takao*; et al.

New Physics; Sae Mulli, 73(12), p.1062 - 1066, 2023/12

https://doi.org/10.3938/NPSM.73.1062

Fundamental research of X-ray absorption imaging for elemental identification using a secondary target

Nakae, Masanori*; Matsuyama, Tsugufumi*; Murakami, Masashi; Yoshida, Yukihiko; Machida, Masahiko; Tsuji, Koichi*

Advances in X-Ray Chemical Analysis, Japan, 54, p.89 - 99, 2023/03

Fundamental research on X-ray absorption imaging for elemental identification was studied. A secondary target was applied to obtain X-ray absorption images above and below the X-ray absorption edge of the target element. X-rays from an X-ray tube were irradiated to the secondary target, where the characteristic X-rays were emitted that were irradiated to the sample. X-ray absorption images were acquired with an exposure time of a few seconds with an X-ray camera. In this technique, it is difficult to change the energy of X-rays as we want, however we can apply this technique for imaging the specific element. Metal foil sample composed of Al, Cu, and Ni was analyzed. To obtain an X-ray elemental image of Ni, two X-ray absorption images were taken using the X-rays above and below the Ni K-edge. X-rays of Cu K and Zn K were prepared by using Cu and Zn plates as the secondary target. Finally, the Ni elemental image was obtained by subtracting two images. Furthermore, the X-ray camera had a function of setting critical energies for imaging, thus it was demonstrated that an X-ray elemental image of Ni was obtained using a single secondary target without changing the secondary target.

Application of high-energy-resolution X-ray absorption spectroscopy at the U L-edge to assess the U(V) electronic structure in FeUO

Yomogida, Takumi; Akiyama, Daisuke*; Ouchi, Kazuki; Kumagai, Yuta; Higashi, Kotaro*; Kitatsuji, Yoshihiro; Kirishima, Akira*; Kawamura, Naomi*; Takahashi, Yoshio*

Inorganic Chemistry, 61(50), p.20206 - 20210, 2022/12

https://doi.org/10.1021/acs.inorgchem.2c03208

FeUO was studied to clarify the electronic structure of U(V) in a metal monouranate compound. We obtained the peak splitting of HERFD-XANES spectra utilizing high-energy-resolution fluorescence detection-X-ray absorption near edge structure (HERFD-XANES) spectroscopy at the U L-edge, which is a novel technique in the U(V) compounds. Theoretical calculations revealed that the peak splitting was caused by splitting the 6d orbital of U(V). Such distinctive electronic states are of major interest to researchers and engineers working in various fields, from fundamental physics to the nuclear industry and environmental sciences for actinide elements.

Gamma-ray observations at the coastal area of Japan Sea in winter seasons

Tsuchiya, Harufumi; Enoto, Teruaki*; Wada, Yuki*; Furuta, Yoshihiro; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Umemoto, Daigo*; Makishima, Kazuo*; GROWTH Collaboration*

Proceedings of Science (Internet), 358, p.1163_1 - 1163_6, 2021/07

https://doi.org/10.22323/1.358.1163

Processes affecting land-surface dynamics of I impacted by atmospheric I releases from a spent nuclear fuel reprocessing plant

Ota, Masakazu; Terada, Hiroaki; Hasegawa, Hidenao*; Kakiuchi, Hideki*

Science of the Total Environment, 704, p.135319_1 - 135319_15, 2020/02

https://doi.org/10.1016/j.scitotenv.2019.135319

Land-surface transfers of I are modeled and incorporated into a land-surface model (SOLVEG-II), and the model was applied to the observed transfer of I at a vegetated field impacted by atmospheric releases of I from Rokkasho reprocessing plant during 2007 to investigate the importance of each I-transfer pathway. The model calculation revealed that contamination of leaves of wild bamboo grasses was mostly caused by foliar adsorption of I (81%) induced via wet deposition of I. Wet deposition of I was the main I-input to the soil, ten-fold the dry deposition of I; however, the deposition of I during 2007 was only 2% of the model-assumed I that pre-existed in the soil; indicating the importance of long-term accumulation of I in soils. The model calculation also revealed that root uptake of I, not methylation, control the long-term turnover of soil I.

Impact of ferrous iron dosing on iron and phosphorus solids speciation and transformation in a pilot scale membrane bioreactor

Wu, H.*; Wang, Y.*; Ikeda, Atsushi; Miller, C. J.*; Waite, T. D.*

Environmental Science; Water Research & Technology, 5(8), p.1400 - 1411, 2019/08

AA2019-0201.pdf:0.72MB

https://doi.org/10.1039/C9EW00225A

In this study, the distributions of iron and phosphorus species in a 1.25 m pilot scale submerged membrane bioreactor dosed with Fe(II) salts to either the membrane chamber or the 1st anoxic chamber were determined using X-ray absorption spectroscopy (XAS) at the iron and phosphorus K-edges. Significant differences in the distribution of Fe species were evident at the commencement of dosing depending on the chamber to which Fe(II) was dosed though these differences were much less distinct by the time steady state conditions were achieved. Both the co-precipitation of P with Fe and adsorption of phosphorus to iron oxides play important roles with regard to the removal of phosphorus from the MBR supernatant with the results of this work suggesting that P removal via formation of Fe(III)-phosphate mineral species is preferred if Fe(II) is dosed to the membrane chamber rather than the 1st anoxic chamber.

Importance of root uptake of CO on C transfer to plants impacted by below-ground CH release

Ota, Masakazu; Tanaka, Taku*

Journal of Environmental Radioactivity, 201, p.5 - 18, 2019/05

https://doi.org/10.1016/j.jenvrad.2019.01.012

CH released from deep underground radioactive waste disposal facilities can be a belowground source of CO owing to microbial oxidation of CH to CO in soils. Environmental C models assume that the transfer of CO from soil to plant occurs via foliar uptake of CO. Nevertheless, the importance of CO root uptake is not well understood. In the present study, belowground transport and oxidation of CH were modeled and incorporated into an existing land surface CO model (SOLVEG-II) to assess the importance of root uptake on CO transfer to plants. Performance of the model in calculating the belowground dynamics of CH was validated by simulating a field experiment of CH injection into subsoil. The model was then applied to C transfer in a hypothetical ecosystem impacted by continuous CH input from the water table (bottom of one-meter thick soil). In a shallowly rooted ecosystem with rooting depth of 11 cm, foliar uptake of CO was significant, accounting for 80% of the C accumulation in the leaves. In a deeply rooted ecosystem (rooting depth of 97 cm), where the root penetrated to depths close to the water-table, more than half (63%) the C accumulated in the leaves was transferred by the root uptake. We found that CO root uptake in this ecosystem depended on the distribution of methane oxidation in the soil; all C accumulated in the leaves was transferred by the root uptake when methane oxidation occurred at considerable depths (e-folding depths of 20 cm, or 80 cm). These results indicate that CO root uptake contributes significantly to CO transfer to plants if CH oxidation occurs at great depths and roots penetrate deeply into the soil.

High temperature oxidation test of simulated BWR fuel bundle in steam-starved conditions

Yamazaki, Saishun; Pshenichnikov, A.; Pham, V. H.; Nagae, Yuji; Kurata, Masaki; Tokushima, Kazuyuki*; Aomi, Masaki*; Sakamoto, Kan*

Proceedings of Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2018) (Internet), 8 Pages, 2018/10

It is predictively evaluated that degradation of fuel assembly proceeded in a certain steam-starved condition at the early stage of a SA at 1F unit 2 (BWR). As for PWR fuel assembly, effective steam flow rate was properly indicated by normalizing to a unit of g-HO/sec/rod which is used as an important parameter for evaluating fuel degradation progression. Due to the inhomogeneous configuration of BWR fuel assembly, the difference of Zry oxidation and hydrogen uptake between the inside and outside of the channel box cannot be properly evaluated by this normalization. Instead of g-HO/sec/rod, proper evaluation unit for BWR configuration is necessary. To accumulate Zry oxidation and hydrogen uptake data for steam-starved conditions, high temperature oxidation tests were performed using a simulated BWR fuel bundle sample. The use of equivalent diameter of the cross section of BWR fuel assembly was proposed for normalization of effective steam flow rate.

Visualization technique with the energy-resolved neutron imaging system, RADEN

Kai, Tetsuya; Shinohara, Takenao; Hiroi, Kosuke; Su, Y. H.; Oikawa, Kenichi

Hihakai Kensa, 67(5), p.209 - 216, 2018/05

no abstracts in English

Micro-orientation control of silicon polymer thin films on graphite surfaces modified by heteroatom doping

Shimoyama, Iwao; Baba, Yuji; Hirao, Norie*

Advances in Engineering (Internet), 1 Pages, 2018/02

The performance of organic devices largely depends on molecular orientation in organic films. Whereas micro-orientation control of organic molecules is an indispensable technology for integration of organic devices, the method has not been established. We attempted to control micro-orientation of polydimethylsilane (PDMS) thin films by deposition of PDMS on graphite substrates modified by hetero atom doping using ion beam. Polarization dependence measurements of X-ray absorption spectroscopy and molecular orbital calculations clarified that PDMS films have lying, standing, and random orientations on the non irradiated, N-irradiated, and Ar-irradiated graphite surfaces, respectively. Furthermore, photoemission microscopy observation clarified that a PDMS film showed micro-patterns on a graphite surface with a microstructure on the order of m by separating N-irradiated and non irradiated areas. These results demonstrate our method is promising for micro-orientation of organic molecules.