Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; Kobayashi, Tomoharu; Mitsuguchi, Takehiro; Murakami, Osamu; et al.
JAEA-Review 2025-035, 29 Pages, 2025/10
JAEA-Review-2025-035.pdf:1.12MB
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2025. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Asamori, Koichi; Sueoka, Shigeru; Kobayashi, Tomoharu; Nishiyama, Nariaki; Tanaka, Kiriha; Murakami, Osamu; Fukuda, Shoma; Ogata, Manabu; Uchida, Mao; Komatsu, Tetsuya; et al.
JAEA-Research 2025-007, 99 Pages, 2025/10
JAEA-Research-2025-007.pdf:12.36MB
This annual report documents the progress of research and development (R&D) in the 3rd fiscal year of the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028) to provide the scientific base for assessing geosphere stability for long-term isolation of high-level radioactive waste. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. The current status of R&D activities with previous scientific and technological progress is summarized.
Jinno, Satoshi; Matsubara, Akihiro*; Fujita, Natsuko; Kimura, Kenji
Isotope News, (801), p.2 - 5, 2025/10
Accelerator Mass Spectrometry (AMS) is widely used in archaeology and geosciences, and since the 2000s, downsized AMS with an acceleration voltage of 200
500 kV has been put to practical use mainly for 
C dating. However, the beam divergence due to collisions with gases increases at accelerating energies below 100 keV, resulting in a decrease in transmittance. Therefore, we are investigating charge conversion and dissociation of interfering molecules on KCl, SnTe, and Au crystal surfaces using the crystal surface stripper method we have developed. In this article, we report on the position of our research and the current progress.
Fujita, Natsuko; Miyake, Masayasu; Matsubara, Akihiro*; Ishii, Masahiro*; Jinno, Satoshi; Watanabe, Takahiro; Nishio, Tomohiro*; Ogawa, Yumi; Omae, Akiomi*; Kimura, Kenji; et al.
Dai-36-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.90 - 92, 2025/03
The JAEA-AMS-TONO facility at the Tono Geoscience Center, JAEA has three accelerator mass spectrometers. We report the present status of the JAEA-AMS-TONO.
Minamitani, Fumina; Nishio, Tomohiro*; Fujita, Natsuko; Maeta, Yusuke; Miyake, Masayasu; Matsubara, Akihiro*; Uno, Sadanori*; Omae, Akiomi*; Jinno, Satoshi; Watanabe, Takahiro
Dai-25-Kai AMS Shimpojiumu Hokokushu (Internet), 4 Pages, 2025/00
no abstracts in English
Jinno, Satoshi; Matsubara, Akihiro*; Fujita, Natsuko; Kimura, Kenji
Nuclear Instruments and Methods in Physics Research B, 557, p.165545_1 - 165545_4, 2024/12
Times Cited Count：1 Percentile：30.35(Instruments & Instrumentation)This study introduces the development of a downsized Accelerator Mass Spectrometry (AMS) system aiming to enhance accessibility and cost-effectiveness in radiocarbon analysis. The "crystal surface stripper method" is introduced as a solution to challenges in AMS downsizing, demonstrating effective ion detection with a smaller angular spread compared to conventional gas stripper methods. The experimental results provide insights into charge conversion capabilities, scattering angle broadening, and energy loss associated with surface scattering.
Niwa, Masakazu; Shimada, Koji; Sueoka, Shigeru; Ishihara, Takanori; Hakoiwa, Hiroaki; Asamori, Koichi; Murakami, Osamu; Fukuda, Shoma; Ogita, Yasuhiro; Kagami, Saya; et al.
JAEA-Research 2024-013, 65 Pages, 2024/11
JAEA-Research-2024-013.pdf:4.22MB
This annual report documents the progress of research and development (R&D) in the 2nd fiscal year of the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028) to provide the scientific base for assessing geosphere stability for long-term isolation of high-level radioactive waste. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. The current status of R&D activities with previous scientific and technological progress is summarized.
Niwa, Masakazu; Shimada, Akiomi; Asamori, Koichi; Sueoka, Shigeru; Komatsu, Tetsuya; Nakajima, Toru; Ogata, Manabu; Uchida, Mao; Nishiyama, Nariaki; Tanaka, Kiriha; et al.
JAEA-Review 2024-035, 29 Pages, 2024/09
JAEA-Review-2024-035.pdf:1.24MB
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency (JAEA), in fiscal year 2024. The objectives and contents of this research are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Fujita, Natsuko; Miyake, Masayasu; Matsubara, Akihiro*; Ishii, Masahiro*; Takahashi, Yuto*; Watanabe, Takahiro; Jinno, Satoshi; Nishio, Tomohiro*; Ogawa, Yumi; Kimura, Kenji; et al.
Dai-24-Kai AMS Shimpojiumu Hokokushu (Internet), 3 Pages, 2024/03
The JAEA-AMS-TONO facility at the Tono Geoscience Center, JAEA has three accelerator mass spectrometers. We report the present status of the JAEA-AMS-TONO.
Fujita, Natsuko; Miyake, Masayasu; Matsubara, Akihiro*; Ishii, Masahiro*; Watanabe, Takahiro; Jinno, Satoshi; Nishio, Tomohiro*; Ogawa, Yumi; Kimura, Kenji; Shimada, Akiomi; et al.
Dai-35-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.17 - 19, 2024/03
The JAEA-AMS-TONO facility at the Tono Geoscience Center, JAEA has three accelerator mass spectrometers. We report the present status of the JAEA-AMS-TONO.
Fujita, Natsuko; Matsubara, Akihiro*; Jinno, Satoshi; Kimura, Kenji
Hoshasen (Internet), 48(4), p.137 - 138, 2024/02
We have been developing a downsized AMS with a size of about 2 m 
2 m. This AMS is developed to demonstrate a new method of separating same-mass molecules, which are interfering nuclides during AMS measurement of carbon-14, using ion channeling.
10
W/cm
Skobelev, I. Yu.*; Ryazantsev, S. N.*; Kulikov, R. K.*; Sedov, M. V.*; Filippov, E. D.*; Pikuz, S. A.*; Asai, Takafumi*; Kanasaki, Masato*; Yamauchi, Tomoya*; Jinno, Satoshi; et al.
Photonics (Internet), 10(11), p.1250_1 - 1250_11, 2023/11
Times Cited Count：3 Percentile：33.60(Optics)It is challenging to clearly distinguish the impacts of the optical field and collisional ionization in the evolution of the charge state of a plasma produced when matter interacts with high-intensity laser pulses. In this work, time-dependent calculations of plasma kinetics are used to show that it is possible only when low-density gaseous targets with sufficiently small clusters are used. In the case of Ar plasma, the upper limit of the cluster radius was estimated to be 
m.
Matsubara, Akihiro*; Fujita, Natsuko; Miyake, Masayasu; Ishii, Masahiro*; Watanabe, Takahiro; Kokubu, Yoko; Nishio, Tomohiro*; Ogawa, Yumi; Jinno, Satoshi; Kimura, Kenji; et al.
JAEA-Conf 2022-002, p.55 - 62, 2023/03
We report the present status of the JAEA-AMS-TONO. Particularly, the destructions of varistors used in the beamline equipment will be presented. The cause of the destruction as well as implementation of the safety measures are mentioned.
Fujita, Natsuko; Miyake, Masayasu; Matsubara, Akihiro*; Ishii, Masahiro*; Watanabe, Takahiro; Jinno, Satoshi; Nishio, Tomohiro*; Ogawa, Yumi; Yamamoto, Yusuke; Kimura, Kenji; et al.
Dai-23-Kai AMS Shimpojiumu Hokokushu, p.1 - 4, 2022/12
The JAEA-AMS-TONO facility at the Tono Geoscience Center, JAEA has three accelerator mass spectrometers. We report the present status of the JAEA-AMS-TONO.
Jinno, Satoshi; Fujita, Natsuko; Tanuma, Hajime*
Dai-23-Kai AMS Shimpojiumu Hokokushu, p.89 - 92, 2022/12
The measurement of chlorine-36 (
Cl) in AMS, which is important for the dating of saline groundwater, is more difficult than other nuclides due to the isobaric interference by sulfur-36 (S). In general, acceleration voltages of 6 MV or higher are required to separate Cl and S. Therefore, this study aims to develop an ion funnel reaction cell and incorporate it into the low energy side of JAEA-AMS-TONO-5MV to selectively suppress S.
Fujita, Natsuko; Matsubara, Akihiro; Kimura, Kenji; Jinno, Satoshi; Kokubu, Yoko
Nuclear Instruments and Methods in Physics Research B, 532, p.13 - 18, 2022/12
Times Cited Count：2 Percentile：26.81(Instruments & Instrumentation)Over the last decade, significant technological advances were made to downsize the AMS systems. Japan Atomic Energy Agency has started a project for developing a prototype downsized AMS system (with the footprint of the system is 1.9 m 1.9 m) based on the surface stripper technique. Although the system configuration using an ion source, magnets, and detectors is similar to that in conventional systems, there is no tandem accelerator as well as a gas stripper. The ion acceleration is provided in the ion source (maximum ion energy 40 keV). For proof-of-principle experiments, we have planned two steps: (1) Observation of the specular reflection and the dissociation by using a compact electrostatic analyzer located just behind the stripper, and (2) Demonstration of C measurement, along with the experimental confirmation of the isobar suppression capability of the surface stripper.
Yogo, Akifumi; Sakaki, Hironao; Fukuda, Yuji; Jinno, Satoshi; Kanasaki, Masato; Kiriyama, Hiromitsu; Shimomura, Takuya; Ogura, Koichi; Mori, Michiaki; Bolton, P.; et al.
Journal of Physics; Conference Series, 688(1), p.012128_1 - 012128_4, 2016/03
Times Cited Count：0 Percentile：0.00(Astronomy & Astrophysics)Kanasaki, Masato; Jinno, Satoshi*; Sakaki, Hironao; Kondo, Kiminori; Oda, Keiji*; Yamauchi, Tomoya*; Fukuda, Yuji
Plasma Physics and Controlled Fusion, 58(3), p.034013_1 - 034013_6, 2016/03
Times Cited Count：28 Percentile：78.92(Physics, Fluids & Plasmas)In order to understand the synergetic interplay between the Coulomb explosion of clusters and the background gas dynamics, we have conducted ion acceleration experiments using CO
clusters (250 nm in dia.) embedded in background H gas with the J-KAREN laser (1 J, 40 fs, 10
contrast) at JAEA-KPSI. By a careful analysis of etch pit positions on CR-39 and their structures including the etch pit growth behavior analysis with the multi-step etching technique, energy spectra for protons from the background gas and carbon/oxygen ions from the clusters are obtained separately. The maximum energies of protons and carbon/oxygen ions are determined as 1.6 MeV and 1.1 MeV/u, respectively. Based on the experimental results, the acceleration mechanism of the background gas ions induced by Coulomb explosion of clusters is discussed with the help from numerical simulations which employ a particle-in-cell (PIC) method including relaxation and ionization processes of plasma particles.
Kanasaki, Masato; Jinno, Satoshi; Sakaki, Hironao; Faenov, A.*; Pikuz, T.*; Nishiuchi, Mamiko; Kiriyama, Hiromitsu; Kando, Masaki; Sugiyama, Akira; Kondo, Kiminori; et al.
Radiation Measurements, 83, p.12 - 14, 2015/12
Times Cited Count：4 Percentile：28.96(Nuclear Science & Technology)An inhomogeneous spatial distribution of laser accelerated carbon/oxygen ions produced via the hydrodynamic ambipolar expansion of CO clusters has been measured by using CR-39 detectors. An inhomogeneous etch pits spatial distribution has appeared on the etched CR-39 detector installed on the laser propagation direction, while homogeneous ones are appeared on those installed at 45
and 90 from the laser propagation direction. From the range of ions in CR-39 obtained by using the multi-step etching technique, the averaged energies of carbon/oxygen ions for all directions are determined as 0.78 
0.09 MeV/n. The number of ions in the laser propagation direction is about 1.5 times larger than those in other directions. The inhomogeneous etch pits spatial distribution in the laser propagation direction could originate from an ion beam collimation and modulation by the effect of electromagnetic structures created in the laser plasma.
Jinno, Satoshi; Fukuda, Yuji; Sakaki, Hironao; Yogo, Akifumi; Kanasaki, Masato; Kondo, Kiminori; Faenov, A. Ya.; Skobelev, I. Yu.*; Pikuz, T. A.; Boldarev, A. S.*; et al.
Progress in Ultrafast Intense Laser Science XI; Springer Series in Chemical Physics, Vol.109, p.215 - 233, 2015/00
Clusters formed in supersonic gas expansion through a three-staged conical nozzle have been verified by measuring the angular distribution of the light scattered from cluster target. The size distirbutions of the clusters are calculated based on the Mie theory. The reliability of the size measurement is verified to be an experimental error of 10% using standard particles. The mean sizes of CO clusters for the cases of CO/H and CO/He mixed-gas targets are estimated to be 0.26 
m and 0.22 m, respectively. For the CO/H, the cluster density is estimated to be 5.5 
clusters/cm
by measuring the attenuation of the laser beam intensity. Furthermore, total gas density profiles are obtained via the Abel inversion from the phase shift of the light passing through the target using an interferometer. The variation of the cluster mass fraction along the radial direction of the target is almost constant, which is consistent with a Boldarev's model.
