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Cs/
Cs isotope ratioShimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Takeda, Seiji
Journal of Radioanalytical and Nuclear Chemistry, 333(12), p.6297 - 6310, 2024/12
Times Cited Count：0 Percentile：0.00(Chemistry, Analytical)
O
submicron spherical particlesKobayashi, Satoru*; Nomura, Eiji*; Chiba, Momoko*; Kawamura, Yukihiko*; Oishi, Kazuki*; Hiroi, Kosuke; Suzuki, Junichi*
Journal of Magnetism and Magnetic Materials, 569, p.170410_1 - 170410_9, 2023/03
Times Cited Count：3 Percentile：45.25(Materials Science, Multidisciplinary)
O
submicron particles studied by polarized small-angle neutron scatteringNomura, Eiji*; Chiba, Momoko*; Matsuo, Sakoto*; Noda, Chiaki*; Kobayashi, Satoru*; Manjanna, J.*; Kawamura, Yukihiko*; Oishi, Kazuki*; Hiroi, Kosuke; Suzuki, Junichi*
AIP Advances (Internet), 12(3), p.035034_1 - 035034_5, 2022/03
Times Cited Count：5 Percentile：49.13(Nanoscience & Nanotechnology)Cs/Cs isotopic ratio in soil collected near Fukushima Daiichi Nuclear Power Station through mass spectrometryShimada, Asako; Tsukahara, Takehiko*; Nomura, Masao*; Kim, M. S.*; Shimada, Taro; Takeda, Seiji; Yamaguchi, Tetsuji
Journal of Nuclear Science and Technology, 58(11), p.1184 - 1194, 2021/11
Times Cited Count：6 Percentile：61.34(Nuclear Science & Technology)Determining the completeness of nuclear reactor decommissioning is an important step in safely utilizing nuclear power. For example, Cs from the Fukushima Daiichi Nuclear Power Station (FDNPS) accident can be treated as background radioactivity, so determining the origin of Cs is essential. To accomplish this, measuring the Cs/Cs isotope ratio can be useful, so this study optimized a solvent extraction method, with calix[4]arene-bis(t-octylbenzo-crown-6) [BOBCalixC6] in 1-octanol, to purify radioactive Cs, radiocesium, from a solution of major environmental soil elements and mass spectrometry interference elements. This optimized method was applied to Cs purification in soil samples (40 g), and the final solutions contained a total of 10
g/ml of the major soil elements and ng/ml concentrations at most of interfering elements. Soil samples collected near the FDNPS were then purified, and the Cs/Cs isotope ratios were measured, using both thermal ionization mass spectrometry (TIMS) and triple quadrupole induced coupled plasma mass spectrometry (ICP-QQQ). The results of each of these measurements were compared, and we found that Cs isotope ratios obtained by TIMS were more precise, by an order of magnitude, while the ICP-QQQ results possessed good abundance sensitivities. A slightly higher Cs/Cs ratio in the northwest area of the FDNPS was observed, while other areas exhibited similar values, all within the measurement error range, which indicated different origins of radiocesium. These results agreed with previously reported 
Cs/Cs activity distributions, suggesting that this ratio may be useful in identifying radiocesium origins for evaluating future nuclear reactor decommissions.
Yamamoto, Masanobu; Ezura, Eiji*; Hara, Keigo*; Hasegawa, Katsushi*; Nomura, Masahiro; Omori, Chihiro*; Schnase, A.*; Shimada, Taihei; Takagi, Akira*; Takata, Koji*; et al.
JPS Conference Proceedings (Internet), 8, p.012015_1 - 012015_6, 2015/09
The J-PARC MR provides a coasting proton beam for nuclear physics experiments by slow extraction. The longitudinal emittance should be enlarged until the MR flat top to mitigate the microwave instability. We have investigated a Phase Modulation (PM) method by using a High Frequency Cavity (HFC) to increase the emittance. We have performed extensive simulation studies to find the appropriate parameters of the PM through the particle tracking simulation. We found that the effective HFC frequency has linear dependence with the PM frequency, where the emittance is smoothly enlarged. Furthermore, we found that the required HFC voltage is inverse proportional to the square root of the duration time of the PM. These PM properties will be used for the design of the HFC. We describe the particle tracking simulation results of controlled emittance blow-up by the PM.
Shiomi, Yuki*; Nomura, Kentaro*; Kajiwara, Yosuke*; Eto, Kazuma*; Novak, M.*; Segawa, Koji*; Ando, Yoichi*; Saito, Eiji
Physical Review Letters, 113(19), p.196601_1 - 196601_5, 2014/11
Times Cited Count：292 Percentile：99.04(Physics, Multidisciplinary)Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*
Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 81(7), p.543 - 546, 2013/07
Times Cited Count：8 Percentile：19.53(Electrochemistry)The molten state of simulated high-level waste glass and the behavior of ruthenium element in the melt were investigated by using synchrotron radiation based X-ray imaging technique. Melting, generating and moving of bubbles, condensation and sedimentation of ruthenium element were observed dynamically in continuous 12-bit gray-scale images from the CCD camera. X-ray intensity was obtained easily by digitizing gray-scale values in the image. The existence of ruthenium element is emphasized as a black color in the CCD image at X-ray energy higher than the Ru K-absorption edge. Position sensitive imaging X-ray absorption fine structure (XAFS) measurement was also performed to clarify the chemical state of ruthenium element in the melt.
Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*
Proceedings of 4th Asian Conference on Molten Salt Chemistry and Technology & 44th Symposium on Molten Salt Chemistry, Japan, p.47 - 52, 2012/09
The molten state of the simulated high-level waste glass and the behavior of ruthenium element in the melt were investigated by using synchrotron radiation based X-ray imaging technique. Melting, generating and moving of bubbles, condensation and sedimentation of ruthenium element were observed dynamically in continuous 12-bit gray-scale images from the CCD camera. The existence of ruthenium in the X-ray CCD image was emphasized over the energy of Ru K-absorption edge. X-ray intensity was obtained easily by digitalizing gray-scale values in the image. Position sensitive imaging X-ray absorption fine structure (XAFS) measurement was performed to clarify the chemical state of ruthenium element in the melt.
Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Shiwaku, Hideaki; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 11(2), p.127 - 132, 2012/06
Distribution and the chemical state of Ru element in the simulated high-level waste glass were examined by using the synchrotron radiation based X-ray imaging technique. In this technique, a direct X-ray CCD camera is used in place of an ion chamber. Position sensitive X-ray absorption spectra were obtained by analyzing gray scale in images of the X-ray CCD camera. At first, we measured a test sample containing RuO
and Ru metal powder. We successfully obtained information on the Ru distribution in the sample. In addition, the chemical state (oxide or metal ?) of each small Ru-rich spot was evaluated by the corresponding position sensitive XAFS spectrum. The imaging XAFS technique was applied to some simulated high-level waste glass samples. The Ru distribution of the glass sample and their chemical state were confirmed by image analyses. It can be seen that Ru element scattered in the glass sample exists as oxide RuO.
Yamamoto, Masanobu; Nomura, Masahiro; Schnase, A.; Shimada, Taihei; Tamura, Fumihiko; Ezura, Eiji*; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Takagi, Akira*; et al.
Proceedings of 3rd International Particle Accelerator Conference (IPAC '12) (Internet), p.2952 - 2954, 2012/05
In J-PARC RCS, the high intensity beam is delivered to the MR. The longitudinal beam emittance at the RCS extraction should be optimized to avoid the beam loss after the MR injection. In order to match the longitudinal emittance shape between the RCS and the MR, it is desirable to enlarge the longitudinal emittance during the RCS acceleration. We have performed the particle tracking simulation for the controlled longitudinal emittance blow up in the RCS.
Nomura, Takuji; Kaneshita, Eiji*
Journal of the Physical Society of Japan, 81(2), p.024707_1 - 024707_11, 2012/02
Times Cited Count：2 Percentile：18.79(Physics, Multidisciplinary)We analyze theoretically the resonant inelastic X-ray scattering (RIXS) at the Ni 
edge in the stripe-ordered state of La
Sr
NiO at 
= 1/3. In the calculation of RIXS spectra, the stripe-ordered ground state is described within the Hartree-Fock approximation by using a realistic tight-binding model for Ni 3
and O 2
orbitals, and the electron correlations in the electronic excitation processes are taken into account within the random-phase approximation. The calculated RIXS spectrum shows a tail toward the low-energy region when the momentum transfer of photons equals the stripe vector 
, being consistent with a recent experimental result. The origin of this anomalous momentum dependence of RIXS spectra is discussed microscopically.
Nomura, Masahiro; Schnase, A.; Shimada, Taihei; Tamura, Fumihiko; Yamamoto, Masanobu; Sato, Tomonori; Yamamoto, Masahiro; Ezura, Eiji*; Hara, Keigo*; Hasegawa, Katsushi*; et al.
Proceedings of 2nd International Particle Accelerator Conference (IPAC 2011) (Internet), p.107 - 109, 2011/09
J-PARC 3 GeV Rapid Cycling Synchrotron (RCS) and 50 GeV Synchrotron (MR) employ the Magnetic Alloy (MA) loaded RF cavities. We observed the impedance reductions of MR RF cavities. Opening the RF cavities, we found that the impedance reductions were caused by the corrosion on the core cutting surfaces. The copper ions in the cooling water from hollow conductors of main magnets might accelerate the corrosion process.
Nomura, Masahiro; Schnase, A.; Shimada, Taihei; Suzuki, Hiromitsu; Tamura, Fumihiko; Yamamoto, Masanobu; Ezura, Eiji*; Omori, Chihiro*; Hara, Keigo*; Hasegawa, Katsushi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3723 - 3725, 2010/05
We have been operating the RF cavities loaded with MA cores with a high field gradient of more than 20 kV/m since October 2007. We have been measuring the RF cavity impedance at the shutdown periods, and we detected the impedance reductions of RCS RF cavities on January and June 2009. Taking out the RF cavities from the beam line and opening them, we found that many of cores showed a buckling at the inner radius. We report the detail of condition of MA cores and the relation between the impedance reduction and core condition.
Yamamoto, Masanobu; Nomura, Masahiro; Schnase, A.; Shimada, Taihei; Tamura, Fumihiko; Ezura, Eiji*; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Takagi, Akira*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.1940 - 1942, 2010/05
The beam commissioning and user operation have been going at the J-PARC RCS. Some Longitudinal beam gymnastics and the acceleration has been successfully performed under the high intensity operation. We have developed the longitudinal particle tracking code with the beam loading and the space charge effects to evaluate the longitudinal beam emittance. We describe the relation between the acceleration voltage pattern and the beam emittance in the dual harmonic rf and the high intensity operation.
Schnase, A.; Omori, Chihiro*; Tamura, Fumihiko; Ezura, Eiji*; Hara, Keigo*; Hasegawa, Katsushi*; Nomura, Masahiro; Shimada, Taihei; Suzuki, Hiromitsu; Takagi, Akira*; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1077 - 1079, 2010/03
Shimada, Taihei; Yamamoto, Masanobu; Suzuki, Hiromitsu; Toda, Makoto*; Hasegawa, Katsushi*; Omori, Chihiro*; Tamura, Fumihiko; Schnase, A.; Hara, Keigo*; Nomura, Masahiro; et al.
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.1080 - 1082, 2010/03
Few magnetic alloys cores of the RF cavities which are installed in the 3 GeV rapid cycling synchrotron of the J-PARC have buckled after the operation of about two years. We heated cores in the air and measured thermal deformation in order to get information about the buckling process. We report the results.
Schnase, A.; Tamura, Fumihiko; Yamamoto, Masanobu; Nomura, Masahiro; Hasegawa, Katsushi; Shimada, Taihei; Suzuki, Hiromitsu; Omori, Chihiro*; Yoshii, Masahito*; Ezura, Eiji*; et al.
Proceedings of 2009 Particle Accelerator Conference (PAC '09) (DVD-ROM), p.1988 - 1990, 2009/05
Yamamoto, Masanobu; Hasegawa, Katsushi; Nomura, Masahiro; Schnase, A.; Tamura, Fumihiko; Anami, Shozo*; Ezura, Eiji*; Hara, Keigo*; Omori, Chihiro*; Takagi, Akira*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.379 - 381, 2008/06
The calculation code for the acceleration voltage pattern is usually based on the differential equation of the longitudinal synchrotron motion. We have developed the code based on the forward-difference equation which satisfies the synchronization with the bending magnetic field ramping accurately. This is very useful especially at the rapid cycling synchrotron where the ramping rate is high.
Tamura, Fumihiko; Schnase, A.; Nomura, Masahiro; Yamamoto, Masanobu; Hasegawa, Katsushi; Haga, Koichi; Yoshii, Masahito*; Omori, Chihiro*; Toda, Makoto*; Hara, Keigo*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.364 - 366, 2008/06
In the J-PARC RCS (Rapid Cycling Synchrotron) we employ a full-digital LLRF control system to accelerate an ultra-high intensity proton beam. The key feature is the multi-harmonic RF signal generation by using direct digital synthesis (DDS) technology. By employing a full-digital system, highly accurate, stable and reproductive RF voltages are generated in the wide-band RF cavities loaded by magneticalloy (MA) cores. The beam commissioning of the J-PARC RCS has been started in October 2007. The accelerators, the linac and the RCS, show good stability. The beam orbit and the longitudinal beam shape and phase are reproductive from cycle to cycle especially thanks to the stability of the linac energy, the RCS bending field and the frequency and voltage of the RCS RF. This reproductivity makes the beam commissioning efficient. We present the examples of the orbit signals and the longitudinal currentsignals. Also, we discuss the longitudinal beam control performance and future plans.
Schnase, A.; Anami, Shozo*; Ezura, Eiji*; Haga, Kaiichi*; Hara, Keigo*; Hasegawa, Katsushi; Nomura, Masahiro; Omori, Chihiro*; Takagi, Akira*; Tamura, Fumihiko; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.346 - 348, 2008/06
