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Al
GaO
scintillators by gamma-ray-induced positron annihilation lifetime spectroscopyFujimori, Kosuke*; Kitaura, Mamoru*; Taira, Yoshitaka*; Fujimoto, Masaki*; Zen, H.*; Watanabe, Shinta*; Kamada, Kei*; Okano, Yasuaki*; Kato, Masahiro*; Hosaka, Masahito*; et al.
Applied Physics Express, 13(8), p.085505_1 - 085505_4, 2020/08
Times Cited Count：6 Percentile：30.34(Physics, Applied)To clarify the existence of cation vacancies in Ce-doped GdAlGaO (Ce:GAGG) scintillators, we performed gamma-ray-induced positron annihilation lifetime spectroscopy (GiPALS). GiPAL spectra of GAGG and Ce:GAGG comprised two exponential decay components, which were assigned to positron annihilation at bulk and defect states. By an analogy with Ce:YAl
O, the defect-related component was attributed to Al/Ga-O divacancy complexes. This component was weaker for Ce, Mg:GAGG, which correlated with the suppression of shallow electron traps responsible for phosphorescence. Oxygen vacancies were charge compensators for Al/Ga vacancies. The lifetime of the defect-related component was significantly changed by Mg co-doping. This was understood by considering aggregates of Mg
ions at Al/Ga sites with oxygen vacancies, which resulted in the formation of vacancy clusters.
Onoe, Hironori; Kosaka, Hiroshi*; Matsuoka, Toshiyuki; Komatsu, Tetsuya; Takeuchi, Ryuji; Iwatsuki, Teruki; Yasue, Kenichi
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.3 - 14, 2019/06
In this study, it is focused on topographic changes due to uplift and denudation, also climate perturbations, a method which is able to assess the long-term variability of groundwater flow conditions using the coefficient variation based on some steady-state groundwater flow simulation results was developed. Spatial distribution of long residence time area which is not much influenced due to long-term topographic change and recharge rate change during the past one million years was able to estimate through the case study of the Tono area, Central Japan. By applying this evaluation method, it is possible to identify the local area that has low variability of groundwater flow conditions due to topographic changes and climate perturbations from the regional area quantitatively and spatially.
Hosaka, Atsushi; Hiyama, Emiko; Kim, S.-H.*; Kim, H.-C.*; Nagahiro, Hideko*; Noumi, Hiroyuki*; Oka, Makoto; Shirotori, Kotaro*; Yoshida, Tetsuya*; Yasui, Shigehiro*
Nuclear Physics A, 954, p.341 - 351, 2016/10
Times Cited Count：3 Percentile：24.93(Physics, Nuclear)In this paper, we discuss reactions involving charmed baryons to explore their unique features. A well known phenomenon, the separation of the two internal motions of the 
and 
types of a three-quark system is revisited. First we discuss the mass spectrum of low-lying excitations as functions of the heavy quark mass, smoothly connecting the 
and heavy quark limits. The properties of these modes can be tested in the production and decay reactions of the baryons. For the productions, we consider a one step process which excites dominantly mode excitations. We find abundant production rates for some of excited states. For decays, we study pion emission process, which provides a clean tool to test the structure of heavy quark systems due to well controlled low energy dynamics of the pion and quark. Both productions and decays of the charmed baryons are the issues of the future experiments at J-PARC.
Yoshida, Tetsuya*; Hiyama, Emiko*; Hosaka, Atsushi*; Oka, Makoto; Sadato, Katsunori*
Physical Review D, 92(11), p.114029_1 - 114029_19, 2015/12
Times Cited Count：209 Percentile：99.19(Astronomy & Astrophysics)Single- and double-heavy baryons are studied in the constituent quark model. The model Hamiltonian is chosen as a standard one with two exceptions: (1) the color-Coulomb term depends on quark masses and (2) an antisymmetric 
(spin-orbit) force is introduced. Model parameters are fixed by the strange baryon spectra, 
and 
baryons. The masses of the observed charmed and bottomed baryons are, then, fairly well reproduced. Our focus is on the low-lying negative-parity states, in which the heavy baryons show specific excitation modes reflecting the mass differences of heavy and light quarks. By changing quark masses from the SU(3) limit to the strange quark mass, and, further, to the charm and bottom quark masses, we demonstrate that the spectra change from the SU(3) symmetry patterns to the heavy-quark-symmetry ones.
Yabashi, Makina*; Tanaka, Hitoshi*; Tanaka, Takashi*; Tomizawa, Hiromitsu*; Togashi, Tadashi*; Nagasono, Mitsuru*; Ishikawa, Tetsuya*; Harries, J.; Hikosaka, Yasumasa*; Hishikawa, Akiyoshi*; et al.
Journal of Physics B; Atomic, Molecular and Optical Physics, 46(16), p.164001_1 - 164001_19, 2013/08
Times Cited Count：73 Percentile：94.70(Optics)Tokiwa, Tetsuya; Asamori, Koichi; Niizato, Tadafumi; Nohara, Tsuyoshi; Matsuura, Yuki*; Kosaka, Hideki*
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.407 - 413, 2010/10
In this study, we present the preliminary results for the estimation of a horizontal crustal movement by using geodetic and geological approach in the Horonobe area, northern Hokkaido, Japan. The estimations have been carried out by using a GPS data and a geological cross section obtained by applying balanced-section method. As results of this study, both of the shortening rates estimated by GPS data and balanced-section method indicate several millimeters per year. Namely, there is no contradiction between geodetic and geological data, and it is considered that Horonobe area is still situated similar tendency and magnitude of a crustal movement. Geodetic data is not usually used to evaluate the long-term crustal movement. However, the results of this study indicate that geodetic data provide valuable information for estimating the long-term crustal movement in the area.
Agui, Akane; Asahi, Toru*; Sayama, Junichi*; Mizumaki, Masaichiro*; Tanaka, Masahito*; Osaka, Tetsuya*
Journal of Magnetism and Magnetic Materials, 320(22), p.3015 - 3018, 2008/11
Times Cited Count：1 Percentile：5.70(Materials Science, Multidisciplinary)no abstracts in English
Co
/Pd multilayered filmsTanaka, Masahito*; Asahi, Toru*; Agui, Akane; Mizumaki, Masaichiro*; Sayama, Junichi*; Osaka, Tetsuya*
Journal of Physics D; Applied Physics, 41(5), p.055003_1 - 055003_4, 2008/03
Times Cited Count：5 Percentile：22.12(Physics, Applied)no abstracts in English
Co
measured using soft X-ray magnetic circular dichroismAgui, Akane; Mizumaki, Masaichiro*; Asahi, Toru*; Matsumoto, Koji*; Morikawa, Tsuyoshi*; Sayama, Junichi*; Osaka, Tetsuya*
Journal of Physics and Chemistry of Solids, 68(11), p.2148 - 2152, 2007/11
Times Cited Count：9 Percentile：40.74(Chemistry, Multidisciplinary)no abstracts in English
Tanaka, Masahito*; Nakamura, Naomichi*; Asahi, Toru*; Tsumori, Toshihiro*; Agui, Akane; Mizumaki, Masaichiro*; Osaka, Tetsuya*
Physica Status Solidi (C), 3(8), p.2783 - 2786, 2006/09
Times Cited Count：1 Percentile：44.79(Materials Science, Multidisciplinary)no abstracts in English
-added and B-doped effect in Co/Pd multilayered films using soft X-ray absorption and magnetic circular dichroismAgui, Akane; Asahi, Toru*; Sayama, Junichi*; Kawaji, Jun*; Mizumaki, Masaichiro*; Tanaka, Masahito*; Osaka, Tetsuya*
Journal of Physics D; Applied Physics, 39(14), p.2881 - 2885, 2006/07
Times Cited Count：1 Percentile：4.30(Physics, Applied)no abstracts in English
-edge of perpendicular magnetic DyCo filmsAgui, Akane; Mizumaki, Masaichiro*; Asahi, Toru*; Sayama, Junichi*; Matsumoto, Koji*; Morikawa, Tsuyoshi*; Matsushita, Tomohiro*; Osaka, Tetsuya*; Miura, Yoshimasa*
Journal of Alloys and Compounds, 408-412, p.741 - 745, 2006/02
Times Cited Count：7 Percentile：45.42(Chemistry, Physical)no abstracts in English
-edges of Tb
FeCo
perpendicular magnetization filmsAgui, Akane; Mizumaki, Masaichiro*; Asahi, Toru*; Sayama, Junichi*; Matsumoto, Koji*; Morikawa, Tsuyoshi*; Nakatani, Takeshi; Matsushita, Tomohiro*; Osaka, Tetsuya*; Miura, Yoshimasa*
Transactions of the Magnetics Society of Japan, 4(4-2), p.326 - 329, 2004/11
The electronic and spin state of the perpendicular magnetization film TbFeCo was investigated by means of magnetic circular dichroism spectroscopy for each element. The samples are TbFeCo while the ratio of a rare-earth metal Tb to transition metals Fe and Co is constant, the composition ratio of Fe and Co is changed. Changing the ratio, we estimated the expected orbital moments 
of Tb 4f electrons. The macroscopic magnetic property is studied from the microscopic point of view.
Agui, Akane; Mizumaki, Masaichiro*; Matsushita, Tomohiro*; Asahi, Toru*; Kawaji, Jun*; Sayama, Junichi*; Osaka, Tetsuya*
Journal of Applied Physics, 95(12), p.7825 - 7831, 2004/06
Times Cited Count：6 Percentile：27.38(Physics, Applied)The electronic and spin states of [Co/Pd] multilayered perpendicular magnetization films with various seedlayers have been investigated by means of soft X-ray absorption and magnetic circular dichroism spectroscopy at the Co 
-edges. The expectation values of the orbital angular momentum and the spin angular momentum 
of Co atom in the [Co/Pd] multilayered film were estimated using the sum rule. It was found that the seedlayer changes macroscopic magnetic properties of the [Co/Pd] multilayered film without affecting the electronic and spin states of the upper layers of Co.
Tanaka, Masahito*; Asahi, Toru*; Agui, Akane; Mizumaki, Masaichiro*; Sayama, Junichi*; Osaka, Tetsuya*
no journal, ,
We examined the macroscopic and element selective magnetic properties by Kerr hysteresis loop and X-ray magnetic circular dichroism (MCD) spectroscopy, respectively, of [TbCo]/Pd multilayered films and TbCo single layered films with several TbCo layer thicknesses. We found that the macroscopic magnetic properties of TbCo/Pd and TbCo films were dependent on the TbCo layer thickness by Kerr effect measurement. We estimated the Lz, Sz and Lz/Sz values from MCD measurements at Co L2,3 edges. The values of Lz and Sz of both types of films were the almost same each other, while the clear distinction of Kerr effects was observed.
Onoe, Hironori*; Shiomi, Tetsuya*; Kusano, Tomohiro; Yasue, Kenichi; Kosaka, Hiroshi; Saegusa, Hiromitsu; Takeuchi, Ryuji; Tajikara, Masayoshi*
no journal, ,
To study the methodology for estimation of the influence of long-term topographic and climate change on deep groundwater flow condition, we estimated of paleo-topography and paleo-climate for past several hundred thousand years based on data from research and field investigations and built geological structured model that considered paleo-topography distribution in case of Gifu Tono area. As a result, we showed technique to restore paleo-topography distribution for three dimensions from fluvial terrace surface data dotted along a river in utilizing DEM data and GIS. In addition, we showed estimate method of climate of glacial epoch and quantity of cultivation of groundwater by near-surface hydrological observation data, pollen fossil analysis and expenditure calculation based on them. Furthermore, we built three-dimensional geological structured model that was base on carrying out groundwater flow analysis by utilizing bygones information.
Nohara, Tsuyoshi; Kosaka, Hideki*; Kagohara, Kyoko*; Miwa, Atsushi*; Tokiwa, Tetsuya; Imaizumi, Toshifumi*
no journal, ,
Activity in the fault-related fold zone in the Tenpoku region, where the influence of the interplate coupling is comparatively small, has been investigated to explain the contradiction between geomorphological and geodetic information. Moreover, the actual average shortening rate of the Sarobetsu fault zone was investigated using the balanced cross section analytical method that used 2D Move. The results of this study show that the estimation of the long term crustal shortening rate in a fault-related fold zone, based on information from the geological structure, is important. In this study, it has been confirmed that information on the deformation of the geological structure is consistent to information on the tectonic landform. A multiple lines of evidence approach, including geomorphological, geological and geodetic investigation methods, will reduce uncertainty related to the average shortening rate along the fault of the fault-related fold.
Kusano, Tomohiro; Yasue, Kenichi; Kosaka, Hiroshi; Saegusa, Hiromitsu; Takeuchi, Ryuji; Onoe, Hironori*; Shiomi, Tetsuya*; Tajikara, Masayoshi*
no journal, ,
In this study, we focused on long-term topography change due to uplift, denudation and climate change with ice age and interglacial cycles of natural phenomena, to estimate influence to groundwater flow characteristics, we estimated paleo-topography and paleo-climate and operated groundwater flow simulation in Tono area. Based on terrace area distribution scattered along river, we estimated paleo-topography in three dimensions with DEM data and GIS. we estimated climate of glacial and interglacial age by near-surface hydrological observation data, pollen fossil analysis and expenditure calculation based on them. In hydraulics geological structure model with paleo-topography, we operated groundwater flow simulation on three-dimensional saturation and unsaturation in steady state. It is thought less effect on groundwater flow characteristics change in current terrain from middle terrace area formation. It is important to evaluate influence of groundwater flow characteristics if that form mountains or hills. Change in groundwater flow characteristics with change of recharge rate is limited to high-altitude area compared to ramifications of the mountains.
Taira, Yoshitaka*; Fujimoto, Masaki*; Fujimori, Kosuke*; Kitaura, Mamoru*; Zen, H.*; Okano, Yasuaki*; Hosaka, Masahito*; Yamazaki, Junichiro*; Kato, Masahiro*; Hirade, Tetsuya; et al.
no journal, ,
For general positron sources, radioisotopes such as 
Na are often used. However, there is a problem that positrons cannot probe the deep region of metal materials with a thickness of 1 mm or more. Gamma-ray induced positron annihilation lifetime measurement (GiPALS) is a method for generating positrons in bulk samples with a thickness of several centimeters and samples placed in vessels such as high temperature and/or pressure furnaces. The annihilation lifetime of positrons is about 200 ps for metal materials, so it is important to use gamma rays with a shorter pulse width for GiPALS in order to accurately measure the positron lifetime. We have succeeded in the proof-of-principle experiment for GiPALS of ultra-short pulse gamma rays with a pulse width of 2 ps, which was originally developed using 90
collision laser Compton scattering at UVSOR.
Taira, Yoshitaka*; Fujimoto, Masaki*; Fujimori, Kosuke*; Kitaura, Mamoru*; Zen, H.*; Okano, Yasuaki*; Hosaka, Masahito*; Yamazaki, Junichiro*; Kato, Masahiro*; Hirade, Tetsuya; et al.
no journal, ,
For general positron sources, radioisotopes such as Na are often used. However, there is a problem that positrons cannot probe the deep region of metal materials with a thickness of 1 mm or more. Gamma-ray induced positron annihilation lifetime measurement (GiPALS) is a method for generating positrons in bulk samples with a thickness of several centimeters and samples placed in vessels such as high temperature and/or pressure furnaces. The annihilation lifetime of positrons is about 200 ps for metal materials, so it is important to use gamma rays with a shorter pulse width for GiPALS in order to accurately measure the positron lifetime. We have succeeded in the proof-of-principle experiment for GiPALS of ultra-short pulse gamma rays with a pulse width of 2 ps, which was originally developed using 90 collision laser Compton scattering at UVSOR.
