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Sekiguchi, Tetsuhiro; Yokoyama, Keiichi; Yaita, Tsuyoshi
e-Journal of Surface Science and Nanotechnology (Internet), 20(3), p.186 - 195, 2022/07
Cesium-135 having long life, 2.3 million y, that is contained in nuclear wastes may cause long-term pollution. Technology of isotopic separation of such long lived nuclide is indispensable not only for its volume reduction but also annihilation by nuclear transmutation. The recovery of atomic Cs from molecular CsI is mandatory. We have investigated fullerene C
as a potential absorber for Cs. Angle-resolved X-ray photoelectron spectroscopy, AR-XPS has been used to analyze the depth concentration distribution of Cs. Experiments were performed at soft X-ray beamline BL27A at KEK PF facility. We report on the annealing effect after deposition of Cs and the effect of heating substrate during deposition. For Cs/C sample, the intensity ratio of Cs-3d/C-1s increased in double at the high temperature. This suggests that Cs atoms remain in the material at high temperatures. On the other hand, for CsI/C, the intensity ratio does not change much by elevating temperatures.
Baba, Yuji; Shimoyama, Iwao; Hirao, Norie*
Applied Surface Science, 384, p.511 - 516, 2016/10
Times Cited Count：5 Percentile：25.9(Chemistry, Physical)Chemical states of cesium as well as the other alkali metals (sodium and rubidium) sorbed in micaceous oxides have been investigated by total reflection X-ray photoelectron spectroscopy (TR-XPS). For cesium, it was shown that ultra-trace amount of cesium down to about 100 pg/cm
can be detected by TR-XPS. This amount corresponds to about 200 Bq of 
Cs (t
= 30.2y). It was demonstrated that ultra-trace amount of cesium corresponding to radioactive cesium level can be measured by TR-XPS. As to the chemical states, it was found that core-level binding energy in TR-XPS for trace-level cesium shifted to lower-energy side compared with that for thicker layer. A reverse tendency is observed in sodium. Based on charge transfer within a simple point-charge model, it is concluded that chemical bond between alkali metal and micaceous oxide for ultra-thin layer is more polarized that for thick layer.
Mannan, M. A.*; Baba, Yuji; Kida, Tetsuya*; Nagano, Masamitsu*; Noguchi, Hideyuki*
Materials Sciences and Applications, 6(5), p.353 - 359, 2015/05
The synthesis and structure of hexagonal boron carbonitride (h-BCN) film on polycrystalline diamond surface were reported. Polycrystalline diamond and/or diamond-like carbon were first fabricated on Si (100) and then it was used as substrate. The deposition was performed by radio frequency plasma enhanced chemical vapor deposition. In order to reduce the content of nitrogen void defects, the deposition was performed at the high temperature of 950
C under the working pressure of 2.6 Pa. The typical sample with atomic composition of B
C
N
O
in the h-BCN lattice was characterized by X-ray photoelectron spectroscopy. The fine structure of the film was studied by near-edge X-ray absorption fine structure (NEXAFS) measurements. The B K-edge and N K-edge of NEXAFS spectra revealed that the synthesized h-BCN film has the ideal honeycomb-like BN
configuration without nitrogen void defects.
-FeSi
thin film formation processesYamamoto, Hiroyuki; Yamaguchi, Kenji; Hojo, Kiichi
Thin Solid Films, 461(1), p.99 - 105, 2004/08
Times Cited Count：10 Percentile：46.84(Materials Science, Multidisciplinary)no abstracts in English
Morimoto, Yasutomi*; Sasaki, Masayoshi*; Kimura, Hiromi*; Sakamoto, Keishi; Imai, Tsuyoshi; Okuno, Kenji*
Fusion Engineering and Design, 66-68, p.651 - 656, 2003/09
Times Cited Count：3 Percentile：25.79(Nuclear Science & Technology)no abstracts in English
Yamamoto, Hiroyuki; Baba, Yuji
Journal of the Korean Vacuum Society, 9(S2), p.84 - 88, 2000/11
no abstracts in English
/Si layer by high-energy XPSYamamoto, Hiroyuki; Baba, Yuji
Journal of Surface Analysis, 7(1), p.122 - 127, 2000/03
no abstracts in English
; Kubota, Mitsuru*; *; *
JNC TN8430 98-001, 12 Pages, 1998/11
Leaching experiments were performed with simulated nuclear waste glasses in silica saturated water at 90C for periods of 28 days in order to clarify the alteration mechanism of waste glass under silica saturation. After leaching experiments, the depth profiles of some elements of glass surfaces were measured by ERDA and ESCA. Depth profiles of H and soluble elements, such as B and Na, for the simulated nuclear waste glass after leaching experiments demonstrated the formation of glass hydration layer and the depletion of soluble elements in the glass hydration layer. The results suggest that alteration of nuclear waste glass under silica saturation is attributed to glass hydration and the leaching behaviour of soluble elements depends on the growth of the glass hydration layer.
Shimogori, Kazutoshi*; Tomari, Haruo*; *; Fujiwara, Kazuo*; Masugata, Tsuyoshi*
PNC TJ1074 98-002, 270 Pages, 1998/02
None
; Kusaka, Makoto*
JAERI-Tech 97-025, 20 Pages, 1997/07
no abstracts in English
Yamamoto, Hiroyuki; Baba, Yuji; Sasaki, Teikichi
Photon Factory Activity Report, P. 366, 1995/00
no abstracts in English
Yamamoto, Hiroyuki; Baba, Yuji; Sasaki, Teikichi
Photon Factory Activity Report, (13), P. 352, 1995/00
no abstracts in English
and O ion-implanted Si(100)Yamamoto, Hiroyuki; Baba, Yuji; Sasaki, Teikichi
Surface and Interface Analysis, 23, p.381 - 385, 1995/00
Times Cited Count：17 Percentile：53.88(Chemistry, Physical)no abstracts in English
Shimoyama, Iwao; Hirao, Norie; Baba, Yuji; Okamoto, Yoshihiro; Yaita, Tsuyoshi; Suzuki, Shinichi; Izumi, Toshinori
no journal, ,
no abstracts in English
Baba, Yuji; Shimoyama, Iwao; Hirao, Norie; Izumi, Toshinori
no journal, ,
In order to clarify the chemical states of radioactive cesium in clay minerals, the X-ray photoelectron spectra (XPS) have been measured for cesium and the other alkali metals on oxides and micaceous oxides. Since the number of atoms in radioactive Cs-137 is extremely small, we focused on the adsorption of trace amount of cesium. For this purpose, we applied total reflection XPS (TR-XPS) using synchrotron radiation. For micaceous oxide, the TR-XPS spectra show that the cesium is more positively charged compared with that for thicker layer. It was shown that trace-level cesium in micaceous oxides is ionically bonded at the interlayer due to the negative charge of the micaceous oxide. We consider that the observed unique adsorption-desorption behavior is specific to only trace-level cesium.
Baba, Yuji; Shimoyama, Iwao; Hirao, Norie
no journal, ,
In order to clarify chemical states of radioactive cesium in clay and soil, X-ray photoelectron spectra (XPS) have been measured for cesium sorbed in laminar oxides such as mica. Since the number of atoms in radionuclides such as Cs is extremely small, we have measured XPS spectra under total reflection condition of incident X-rays. This method enabled us to measure XPS spectra for ultra-trace level alkali metals down to 1/1000 monolayer. For rubidium and cesium, the XPS core levels shifted to lower energy side with the decrease in the number of layer. While for sodium, the direction of the energy shift was reverse to those of rubidium and cesium. On the basis of point charge model, it was clarified that the lower the number of layer is, the stronger the iconicity of the chemical bond becomes for rubidium and cesium.
Baba, Yuji; Shimoyama, Iwao; Hirao, Norie
no journal, ,
no abstracts in English
Baba, Yuji; Shimoyama, Iwao
no journal, ,
no abstracts in English
Baba, Yuji; Shimoyama, Iwao
no journal, ,
no abstracts in English
Baba, Yuji; Shimoyama, Iwao
no journal, ,
no abstracts in English
