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Journal Articles

Competition between mass-symmetric and asymmetric fission modes in $$^{258}$$Md produced in the $$^{4}$$He + $$^{254}$$Es reaction

Nishio, Katsuhisa; Hirose, Kentaro; Makii, Hiroyuki; Orlandi, R.; Kean, K. R.*; Tsukada, Kazuaki; Toyoshima, Atsushi*; Asai, Masato; Sato, Tetsuya; Chiera, N. M.*; et al.

Physical Review C, 111(4), p.044609_1 - 044609_12, 2025/04

 Times Cited Count:0 Percentile:0.00(Physics, Nuclear)

JAEA Reports

Annual report of Department of Research Reactor and Tandem Accelerator, JFY2023 (Operation, Utilization and Technical Development of JRR-3, NSRR, Tandem Accelerator, Radio Isotope Production Facility and Tritium Process Laboratory, Decommissioning Activity for JRR-4)

Department of Research Infrastructure Technology Development

JAEA-Review 2024-051, 112 Pages, 2025/03

JAEA-Review-2024-051.pdf:4.33MB

The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor No.3), NSRR (Nuclear Safety Research Reactor), Tandem Accelerator, Radio Isotope Production Facility, and TPL (Tritium Process Laboratory). It is also responsible for the decommissioning of JRR- 4 (Japan Research Reactor No.4) and the management of JRR-1 (Japan Research Reactor No.1) and FEL (Free Electron Laser). This annual report describes the activities of our department in fiscal year of 2023. We carried out the operation and maintenance, utilization, upgrading of utilization techniques, decommissioned JRR-4, safety administration, international cooperation and human resources development. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, outcomes in service and technical developments and so on.

Journal Articles

Vicinage effect on the yield of convoy electrons emitted from thin carbon foil induced by the penetration of 3.5 MeV/atom C$$_{n}$$$$^{+}$$ ions

Shiina, Yoko*; Kinoshita, Ryo*; Funada, Shuhei*; Matsuda, Makoto; Imai, Makoto*; Kawatsura, Kiyoshi*; Sataka, Masao*; Sasa, Kimikazu*; Kaneko, Toshiaki*; Tomita, Shigeo*

Physical Review A, 110(6), p.062826_1 - 062826_7, 2024/12

 Times Cited Count:0 Percentile:0.00(Optics)

Journal Articles

Improved extraction efficiency of radioactive copper produced via accelerator neutrons method through phosphate buffer-enhanced column pre-treatment

Mikhail, M. A. G.*; Kin, Tadahiro*; Eto, Taisei*; Tsukada, Kazuaki

Scientific Reports (Internet), 14, p.27132_1 - 27132_10, 2024/11

 Times Cited Count:0 Percentile:0.00(Multidisciplinary Sciences)

We have studied a straightforward and robust single-step cation exchange separation method to isolate medical copper radioisotopes $$^{64}$$Cu and $$^{67}$$Cu produced in the $$^{nat}$$Zn(n, x) reaction with an accelerator neutrons technique. This study revealed the key role of a phosphate buffer pre-treatment of the cation exchange column in the separation process. It was found that incorporating the phosphate buffer into the column pre-treatment markedly enhances the retention of copper isotopes within the column throughout the separation procedure. This approach yields a high-purity radioactive copper sample with a high extraction efficiency of 94.4% of the initially produced copper, all within a relatively short experimental time frame of approximately 5 h for 100 g of starting material.

JAEA Reports

Application of EBSD as a method for analyzing irradiation damage in ceramics

Fujimura, Yuki; Ishikawa, Norito; Kondo, Keietsu

JAEA-Technology 2024-012, 26 Pages, 2024/10

JAEA-Technology-2024-012.pdf:3.03MB

While ceramic materials exhibit high temperature strength and corrosion resistance, they are also chemically stable. Specifically, aluminum oxide (Al$$_{2}$$O$$_{3}$$) is recognized as one of the highly radiation resistant materials. On the other hand, the precise evaluation of irradiation damage in these materials poses a significant challenge because detecting radiation damage induced in highly radiation-resistant ceramics is difficult. The objective of this study is to evaluate irradiation-induced lattice strain using Electron BackScatter Diffraction (EBSD), a technique commonly employed for damage analysis in metals. Ion irradiation tests were conducted on Al$$_{2}$$O$$_{3}$$, a representative highly radiation-resistant ceramic, at various doses. Through lattice strain analysis using EBSD, we successfully identified irradiation-induced lattice strain in the direction parallel to the irradiation, consistent with previous XRD analysis results. Lattice strain in the direction perpendicular to the irradiation was also detected. It was observed that the lattice strain tends to increase with increasing irradiation damage. In conclusion, lattice strain analysis using EBSD proves to be an effective method for assessing the irradiation effects on ceramics.

Journal Articles

Activation level of the concrete building and pressure vessel in JAEA-Tokai tandem accelerator

Yoshida, Go*; Matsumura, Hiroshi*; Nakamura, Hajime*; Miura, Taichi*; Toyoda, Akihiro*; Masumoto, Kazuyoshi*; Nakabayashi, Takayuki*; Matsuda, Makoto

Journal of Nuclear Science and Technology, 61(10), p.1298 - 1307, 2024/10

 Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)

Journal Articles

SiC sensor wire test by heavy ion beam irradiation, 2

Meigo, Shinichiro; Yamaguchi, Yuji

Proceedings of 21st Annual Meeting of Particle Accelerator Society of Japan (Internet), p.853 - 858, 2024/10

no abstracts in English

JAEA Reports

Annual report of Department of Research Reactor and Tandem Accelerator, JFY2022 (Operation, Utilization and Technical Development of JRR-3, NSRR, Tandem Accelerator, Radio Isotope Production Facility and Tritium Process Laboratory, Decommissioning Activity for JRR-4)

Department of Research Reactor and Tandem Accelerator

JAEA-Review 2024-029, 107 Pages, 2024/08

JAEA-Review-2024-029.pdf:5.18MB
JAEA-Review-2024-029(errata).pdf:0.13MB

The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor No.3), NSRR (Nuclear Safety Research Reactor), Tandem Accelerator, Radio Isotope Production Facility, and TPL (Tritium Process Laboratory). Also decommissioned JRR-4 (Japan Research Reactor No.4) and maintains JRR-1 (Japan Research Reactor No.1) and the FEL (Free Electron Laser). This annual report describes the activities of our department in fiscal year of 2022. We carried out the operation and maintenance, utilization, upgrading of utilization techniques, decommissioned JRR-4, safety administration, international cooperation and human resources development. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, outcomes in service and technical developments and so on.

JAEA Reports

Annual report of Nuclear Science Research Institute, JFY2021

Nuclear Science Research Institute, Sector of Nuclear Science Research

JAEA-Review 2023-050, 178 Pages, 2024/03

JAEA-Review-2023-050.pdf:7.06MB

Nuclear Science Research Institute (NSRI) is composed of Planning and Management Department and six departments, namely Department of Operational Safety Administration, Department of Radiation Protection, Engineering Services Department, Department of Research Reactor and Tandem Accelerator, Department of Criticality and Hot Examination Technology and Department of Decommissioning and Waste Management, and each department manages facilities and develops related technologies to achieve the "Medium- to Long- term Plan" successfully and effectively. And, four research centers which are Advanced Science Research Center, Nuclear Science and Engineering Center, Nuclear Engineering Research Collaboration Center and Materials Sciences Research Center, belong to NSRI. In order to contribute the future research and development and to promote management business, this annual report summarizes information on the activities of NSRI of JFY 2021 as well as the activity on research and development carried out by Collaborative Laboratories for Advanced Decommissioning Science, Nuclear Safety Research Center and activities of Nuclear Human Resource Development Center, using facilities of NSRI.

Journal Articles

Development of standard substance for hydrogen analysis in materials

Ogawa, Hiroaki; Ishikawa, Norito

2023-Nendo Daigaku Kenkyu Josei Gijutsu Kenkyu Hokokusho, p.123 - 134, 2024/03

Evaluation of corrosion and hydrogen embrittlement is important in the quality control of stainless steel and the development of next steel materials assuming a high-pressure hydrogen environment. Typically, a secondary ion mass spectrometer (SIMS) is used to analyze hydrogen in steel materials. The hydrogen concentration of conventional standard substance for hydrogen analysis is as small as 1wt-ppm, which has been a problem in hydrogen analysis. We use a hydrogen-implant method to create a locally higher hydrogen concentration than that of the conventional. Hydrogen concentration analysis has been evaluated using the nuclear reaction analysis (NRA) method at a tandem accelerator. We have succeeded in creating a sample with a higher hydrogen concentration of about 1,900 wt-ppm than that of the conventional in locally.

Journal Articles

Ion tracks and nanohillocks created in natural zirconia irradiated with swift heavy ions

Ishikawa, Norito; Fukuda, Shoma; Nakajima, Toru; Ogawa, Hiroaki; Fujimura, Yuki; Taguchi, Tomitsugu*

Materials, 17(3), p.547_1 - 547_21, 2024/02

 Times Cited Count:2 Percentile:57.76(Chemistry, Physical)

Natural monoclinic zirconia (baddeleyite) was irradiated with 340-MeV Au ions, and the irradiation-induced nanostructures (i.e., ion tracks and nanohillocks) were observed using transmission electron microscopy. The diameter of the nanohillocks is approximately 10 nm, which is similar to the maximum molten region size calculated using the analytical thermal spike model. Ion tracks are imaged as strained regions that maintain their crystalline structure. The cross-sections of most of the ion tracks are imaged as parallelopiped or rectangular contrasts as large as 10 nm. These results strongly indicate that the molten region is recrystallized anisotropically, reflecting the lattice structure. Furthermore, low-density track cores are formed in the center of the ion tracks. The formation of low-density track cores can be attributed to the ejection of molten matter toward the surface.

Journal Articles

Latent ion tracks were finally observed in diamond

Amekura, Hiroshi*; Chettah, A.*; Narumi, Kazumasa*; Chiba, Atsuya*; Hirano, Yoshimi*; Yamada, Keisuke*; Yamamoto, Shunya*; Leino, A. A.*; Djurabekova, F.*; Nordlund, K.*; et al.

Nature Communications (Internet), 15, p.1786_1 - 1786_10, 2024/02

 Times Cited Count:2 Percentile:57.35(Multidisciplinary Sciences)

Injecting high-energy heavy ions in the electronic stopping regime into solids can create cylindrical damage zones called latent ion tracks. Although these tracks form in many materials, none have ever been observed in diamond, even when irradiated with high-energy GeV uranium ions. Here we report the first observation of ion track formation in diamond irradiated with 2-9 MeV C$$_{60}$$ fullerene ions. Depending on the ion energy, the mean track length (diameter) changed from 17 (3.2) nm to 52 (7.1) nm. High resolution scanning transmission electron microscopy (HR-STEM) indicated the amorphization in the tracks, in which $$pi$$-bonding signal from graphite was detected by the electron energy loss spectroscopy (EELS).

Journal Articles

Search for the 6$$alpha$$ condensed state in $$^{24}$$Mg using the $$^{12}$$C+$$^{12}$$C scattering

Fujikawa, Y.*; Kawabata, T.*; Adachi, S.*; Hirose, Kentaro; Makii, Hiroyuki; Nishio, Katsuhisa; Orlandi, R.; Suzaki, Fumi; 13 of others*

Physics Letters B, 848, p.138384_1 - 138384_6, 2024/01

 Times Cited Count:6 Percentile:73.96(Astronomy & Astrophysics)

Journal Articles

Present status of JAEA-Tokai tandem accelerator

Kutsukake, Kenichi; Matsuda, Makoto; Nakamura, Masahiko; Ishizaki, Nobuhiro; Kabumoto, Hiroshi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Nakagawa, Sohei; Abe, Shinichi

Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1080 - 1084, 2023/11

no abstracts in English

Journal Articles

Investigation of niobium surface roughness and hydrogen content with different polishing conditions for performance recovery of superconducting QWRs in JAEA Tokai-Tandem Accelerator

Kamiya, Junichiro; Nii, Keisuke*; Kabumoto, Hiroshi; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; Matsuda, Makoto; Moriya, Katsuhiro; Ida, Yoshiaki*; et al.

e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.344 - 349, 2023/05

no abstracts in English

JAEA Reports

Development of bearing units used in the rotating shaft system for power generation in the JAEA-Tokai Tandem accelerator

Otokawa, Yoshinori; Matsuda, Makoto; Abe, Shinichi

JAEA-Technology 2022-037, 23 Pages, 2023/03

JAEA-Technology-2022-037.pdf:5.38MB

Bearing units of rotating shaft system for power generation in the JAEA-Tokai Tandem accelerator had a short operating life from the beginning of the accelerator installation, and even after replacing the bearing unit, early failures often occurred. Therefore, the quantity and frequency of replacement are large, and a lot of time is spent in regular maintenance performed by opening the accelerator pressure vessel, and solving this problem has been a long-standing concern. As a result of considering the cause of this early failure, it was considered that the load caused by parallel, angular, and axial misalignment of the upper and lower bearing units was the cause. In order to solve this problem, we have developed a bearing unit having metal disc-spring couplings in the upper and lower flanges to allow for parallel, angular, and axial misalignment of bearing units. As a result, it is now possible to allow variations in the distance between castings and parallel, angular, and axial misalignment of the upper and lower bearing units. By installing the developed new bearing unit on the rotating shaft system and making improvements while continuing to use it in actual operation, we succeeded in reducing the early failure and extending the operating life by more than double. With this development, the maintenance time has been reduced to one week by reducing the number of replacing the bearing unit. In addition, we have realized one regular maintenance that was carried out about three times a year, and as a benefit, we were able to reduce the amount of sulfur hexafluoride (SF$$_{6}$$) gas, which is a greenhouse gas, to about 33$$sim$$50% per year. We describe about development of new bearing units and these maintenance status from 2006 to 2020.

JAEA Reports

Annual report of Department of Research Reactor and Tandem Accelerator, JFY2020 (Operation, utilization and technical development of JRR-3, JRR-4, NSRR, Tandem Accelerator, RI Production Facility and Tritium Process Laboratory)

Department of Research Reactor and Tandem Accelerator

JAEA-Review 2022-075, 112 Pages, 2023/03

JAEA-Review-2022-075.pdf:8.25MB

The Department of Research Reactor and Tandem Accelerator is in charge of the operation, utilization and technical development of JRR-3 (Japan Research Reactor No.3), JRR-4 (Japan Research Reactor No.4), NSRR (Nuclear Safety Research Reactor), Tandem Accelerator, RI Production Facility, TPL (Tritium Process Laboratory) and FEL (Free Electron Laser). This annual report describes the activities of our department in fiscal year of 2020. We carried out the operation and maintenance, utilization, upgrading of utilization techniques, safety administration and international cooperation. Also contained are lists of publications, meetings, granted permissions on laws and regulations concerning atomic energy, outcomes in service and technical developments and so on.

JAEA Reports

Proceedings of the 34th Meeting for Tandem Accelerators and their Associated Technologies

Kabumoto, Hiroshi; Nakagawa, Sohei; Matsuda, Makoto

JAEA-Conf 2022-002, 146 Pages, 2023/03

JAEA-Conf-2022-002.pdf:9.89MB

"The 34th Meeting for Tandem Accelerators and their Associated Technologies" was held on July 21-22, 2022 organized by Nuclear Science Research Institute of the Japan Atomic Energy Agency. This meeting was held only on-line for preventing the spread of COVID-19 infection. The purpose of this meeting is contribution of development for related technology and of management of facilities through exchange of information among the researchers and engineers using and operating electrostatics accelerator facilities like tandem accelerators. There were 25 presentations which contains current status report of facility, technical development of accelerator, research of application. The total number of participants was a hundred, from 26 universities, research organizations and industries. This meeting consisted of only oral session, a poster session was not carried out because of on-line meeting. This proceeding compiles the contents of report papers in the meeting.

Journal Articles

Introduction of radiation damage research and atomic physics research at the JAEA tandem accelerator

Ishikawa, Norito

JAEA-Conf 2022-002, p.111 - 115, 2023/03

In this report, some of the research topics related to radiation damage and atomic physics researches utilizing the tandem accelerator at JAEA are introduced.

Journal Articles

40 years of Tokai-tandem history

Matsuda, Makoto

JAEA-Conf 2022-002, p.103 - 110, 2023/03

no abstracts in English

932 (Records 1-20 displayed on this page)