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Nakahara, Masaumi; Sasaki, Misa*; Yamagata, Ryohei*; Koka, Masashi*; Moriguchi, Tetsuji*
Nuclear Instruments and Methods in Physics Research B, 579, p.166229_1 - 166229_6, 2026/10
Times Cited Count：0To decrease secondary radioactive waste, a removal technique of contaminants with ultrafine bubble water has been proposed for decommissioning of nuclear reactors. In this study, removal experiments with ultrafine bubbles were performed with simulated contaminants precipitated Co oxides, and the surface conditions of test specimens were analyzed and evaluated.
Minamitani, Fumina; Nishio, Tomohiro; Fujita, Natsuko; Maeta, Yusuke; Miyake, Masayasu*; Matsubara, Akihiro*; Jinno, Satoshi; Ogita, Yasuhiro; Watanabe, Takahiro
Nuclear Instruments and Methods in Physics Research B, 579, p.166245_1 - 166245_7, 2026/10
Times Cited Count：0The Tono Geoscience Centre has started to build up a small analysis of radiocarbon using cementite. It is characterised by homogeneous target synthesis and stable measurements with high accuracy and low background. In order to establish the optimum cementite preparation method at the centre, the type of iron, conditions of use, reaction yield, reproducibility of measurement and background were investigated. In sample preparation, target production in high yield was successfully achieved by devising the conditions for the use of iron catalysts. Although the measurement conditions are still under investigation, the beam intensity was found to be sufficient for the measurement and the prescisions were relatively high. This presentation will report on the characteristics of small-scale analysis with cementite at this centre.
suppression in ion-irradiated Fe-Cr-Al alloys revealed by high-throughput mappingAbe, Yosuke; Kubo, Atsushi; Geng, D.*; Yamashita, Shinichiro; Okubo, Nariaki; Tsuru, Tomohito; Sasaki, Taisuke*; Yu, H.*; Kasada, Ryuta*; Ukai, Shigeharu
Nuclear Instruments and Methods in Physics Research B, 576, p.166135_1 - 166135_9, 2026/07
We present a high-throughput framework for mapping composition-dependent irradiation hardening in Fe-Cr-Al alloys using diffusion-bonded combinatorial samples (0-45~at.% Cr, 0-25~at.% Al). LOESS interpolation with LOOCV optimization and automated Nix-Gao analysis enables reliable extraction of hardness from 
100 nanoindentations in 15~s, with compositional uncertainty below 3~at.%.Under 10.5~MeV Fe
irradiation to 9.1~dpa at 350
C, hardening is separated into contributions from defect clusters and Cr-rich 
precipitation. Aluminum has a non-monotonic effect on : it promotes precipitation near 5~at.% but suppresses it at higher levels, with suppression beginning at 5~at.-far below the 12~at.% equilibrium threshold-implying irradiation-driven kinetic effects.
Matsubara, Akihiro*; Kokubu, Yoko; Nishio, Kazuhisa*; Kimura, Kenji*; Kashimura, Keiichiro*; Shimada, Koji; Fujita, Natsuko
Nuclear Instruments and Methods in Physics Research B, 568, p.165863_1 - 165863_5, 2025/11
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)We propose a concept for a cesium-free negative ion source based on microwave heating of granular low work function materials, which allows for both safety and high efficiency. This negative ion source features a structure where the plasma region and the negative ion generation region are adjacent within a microwave cavity. In the negative ion generation region, granular low work function materials heated by microwaves are placed. The sample gas entering the plasma region is excited, then it enters the negative ion generation region. Subsequently, it comes into contact with the surface of the low work function material, changes into negative ions, and finally, is extracted by an electric field. One advantage of this negative ion source is that, by using low work function materials in granular form, the reactive area is more than ten times larger compared to conventional negative ion sources using low work function materials.
Yamaguchi, Yuji; Niikura, Megumi*; Mizuno, Rurie*; Tampo, Motonobu*; Harada, Masahide; Kawamura, Naritoshi*; Umegaki, Izumi*; Takeshita, Soshi*; Haga, Katsuhiro
Nuclear Instruments and Methods in Physics Research B, 567, p.165801_1 - 165801_11, 2025/10
Times Cited Count：2 Percentile：47.92(Instruments & Instrumentation)As part of the development of a sample radioactivity calculation program, we have measured radionuclide production probabilities in negative muon nuclear capture to update experimental data and to validate a calculation dataset obtained by a Monte Carlo simulation code. The probabilities have been obtained by an activation experiment on 
Al, 
Si, 
Co, and Ta targets. The obtained probabilities expand the validation scope to the radionuclide production processes outside of the existing data coverage. By comparing the resultant probabilities with the calculated dataset, it has been revealed that the dataset is generally on the safe side in radioactivity estimation and needs to be corrected in the following three cases: (i) isomer production; (ii) radionuclide production by the multiple neutron emission; (iii) radionuclide production by particle emissions involving a proton. The present probabilities and the new findings on the correction provide valuable clues to improvements of the simulation models.
Ogawa, Tatsuhiko; Labonnote, N.*
Nuclear Instruments and Methods in Physics Research B, 567, p.165791_1 - 165791_20, 2025/10
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)The general-purpose particle and heavy ion transport code system, PHITS, developed by the Japan Atomic Energy Agency, was validated against the SINBAD, an internationally recognized benchmark experiment archive for radiation shielding. Unlike the previous PHITS benchmark against SINBAD, which primarily focused on shielding experiments for proton accelerators, this study conducted benchmarking for double-differential neutron yields, activation, residual dose, and microdosimetric quantities induced by protons, electrons, ions, and pions. This allowed for the use of models and databases not previously employed in validation studies, leading to the discovery of previously overlooked issues. While PHITS calculations generally agreed with experimental data within a factor of two, a detailed comparison revealed the need for improvements in several areas. These include: the inability of the high-energy hadron cascade model to calculate the angular momentum of residual nuclei, the underestimation of neutrons below 100 MeV in pion-induced reactions by the same model, the underestimation of proton-rich nuclei by the evaporation model, and the underestimation of high-energy secondary neutrons by the heavy-ion reaction model. These findings will be used as guidelines for future improvements to PHITS.
Costantini, J.-M.*; Guillaumet, M.*; Lelong, G.*; Ishikawa, Norito; Seo, P.*; Yasuda, Kazuhiro*
Nuclear Instruments and Methods in Physics Research B, 558, p.165567_1 - 165567_6, 2025/01
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Radiation damage is studied in ion-irradiated sintered CeO
and (Ce, Gd)O
samples. Near Infra-red (NIR) spectra measurements were carried out by using the diffuse reflectivity mode for all of these sintered samples. Samples were irradiated with 100-MeV Kr, 200-MeV Xe, and 36-MeV W ions. Four broad absorption bands centered at 3700, 4100, 6000, and 7600 cm
(i.e. 0.46, 0.51, 0.74, and 0.94 eV) are deduced from fits of the FTIR spectra for the ion-irradiated CeO and (Ce, Gd)O samples accompanied by a change in color from ivory to green. No such bands are recorded for the virgin (Ce, Gd)O samples with 5, 10, and 15 mol GdO
with an increasing amount of oxygen vacancies. Absorption bands are tentatively assigned to electronic transitions involving cerium vacancy levels in the band gap, which has been also observed under high-energy electron irradiation.
Teshigawara, Makoto; Lee, Y.*; Tatsumoto, Hideki*; Hartl, M.*; Aso, Tomokazu; Iverson, E. B.*; Ariyoshi, Gen; Ikeda, Yujiro*; Hasegawa, Takumi*
Nuclear Instruments and Methods in Physics Research B, 557, p.165534_1 - 165534_10, 2024/12
Times Cited Count：1 Percentile：22.55(Instruments & Instrumentation)At Japanese Spallation Neutron Source in J-PARC, the para-hydrogen fraction was measured by using Raman spectroscopy in-situ for an integrated beam power of 9.4 MW
h at 1 MW operation, to evaluate the functionality of the ferric oxyhydroxide catalyst. This result showed that full functionality of the catalyst was retained up to the 1 MW operation. We attempted to study the effect of neutron scattering driven para to ortho-hydrogen back-conversion rate in the absence of the catalyst effect with a bypass line without catalyst. The measured increase of ortho-hydrogen fraction was 0.44% for an integrated beam power of 2.4 MWh at 500 kW operation, however, which was considered to be due to not only to neutron collisions in cold moderators but also to the high ortho-hydrogen fraction of initially static liquid hydrogen in the bypass line and passive exudation of quasi-static hydrogen in the catalyst vessel to the main loop.
Sato, Tatsuhiko; Hashimoto, Shintaro; M
rquez Damin, J. I.*; Niita, Koji*
Nuclear Instruments and Methods in Physics Research B, 557, p.165535_1 - 165535_8, 2024/12
Times Cited Count：1 Percentile：22.55(Instruments & Instrumentation)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：22.55(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.
Iwamoto, Yosuke; Matsuda, Hiroki*; Meigo, Shinichiro; Yonehara, Katsuya*; Pellemoine, F.*; Liu, Z.*; Lynch, K.*; Yoshida, Makoto*; Yabuuchi, Atsushi*; Yoshiie, Toshimasa*; et al.
Nuclear Instruments and Methods in Physics Research B, 557, p.165543_1 - 165543_8, 2024/12
Times Cited Count：2 Percentile：41.12(Instruments & Instrumentation)The number of displacements per atom is widely used as an indicator of irradiation damage to materials in proton accelerator facilities. Experiments have been carried out on protons below 3 GeV to verify the dpa of metallic materials. However, the dpa for high-energy protons above 3 GeV has not been measured. In order to validate the displacement cross sections of metals in the high-energy region, the electrical resistivity changes of aluminium, copper and tungsten wires at a temperature of 8 K were measured using protons with energy of 120 GeV. The results show that the conventional irradiation damage model of PHITS overestimates the experimental data. On the other hand, the calculation results using the athermal recombination correction model were in agreement with the experimental data.
Minowa, Kazuki*; Watanabe, So; Nakase, Masahiko*; Takahatake, Yoko; Miyazaki, Yasunori; Ban, Yasutoshi; Matsuura, Haruaki*
Nuclear Instruments and Methods in Physics Research B, 556, p.165496_1 - 165496_6, 2024/11
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)In this study, X-ray absorption near edge structure (XANES) spectral analysis and column experiments were used to verify the selectivity of rare earth (RE) ions by alkyl diamide amine (ADAAM) adsorbent. In addition, the interactions between the N atoms of ADAAM and RE ions were evaluated to determine whether any of the RE ions are a valid simulant for developing a mutual separation process for minor actinides (MAs) in highly radioactive liquid waste. It was confirmed that La and Ce interacted with the amine N atom of ADAAM and they showed a peak shift of the N-K edge XANES spectrum; this finding suggested that a soft interaction is an essential factor influencing ion selectivity. Therefore, the selection factor of RE ions by ADAAM adsorbent was similar to that of MAs. It was concluded that RE ions are reasonable species to simulate MAs.
Oguri, Kaori; Hagura, Naoto*; Yamaguchi, Akiko; Okumura, Masahiko; Matsuura, Haruaki*; Tsunashima, Yasumichi; Aoki, Katsumi; Arai, Yoichi; Watanabe, So
Nuclear Instruments and Methods in Physics Research B, 556, p.165516_1 - 165516_8, 2024/11
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Ningyo-toge is the uranium mine that has been operated in Japan. Various radioactive elements such as Uranium (U), and Radium (Ra) are still present in the mine ground water with very small amount, and behavior of those elements is not fully understood. In this study, we investigated the composition of metal oxides and clay minerals in a soil of slag deposit at the mine, and systematics of adsorption structure of various ions were examined. Identifying the composition and chemical forms of minerals present in the soil of slag can provide useful information for the safety assessment and evaluation of influence on the surrounding environment.
- telescope ERDAHarayama, Isao; Hirose, Yasushi*; Sekiba, Daiichiro*
Nuclear Instruments and Methods in Physics Research B, 554, p.165435_1 - 165435_6, 2024/09
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)- telescope elastic recoil detection analysis (ERDA) is a helpful ion beam analysis (IBA) technique for the absolute quantification of multiple light elements in thin films. We have developed a compact - telescope ERDA system to estimate a composition ratio of oxygen and nitrogen in metal oxynitride thin films. Our - telescope ERDA system employs a gas ionization chamber (GIC), which consisted of a U-shaped cathode, while a planar shaped cathode is widely utilized for GICs. The shape of U-shaped cathode is useful to downsize the GIC. The difference of performance between the U-shaped and planar shaped cathodes, however, has not been studied well, yet. In this study, we quantitatively evaluated the influence using the U-shaped cathode on - telescope ERDA. In order to compare the performance of the U-shaped and planar shaped cathode, we measured SrTiO bulk samples as a standard with them. There is no significant difference between the two cathodes from the viewpoint of O recoil yields. These results show that the U-shaped cathode can also be used safely for - telescope ERDA, and that GICs have a flexibility in the electrode shape, which is useful to make GICs more compact.
Arai, Yoichi; Watanabe, So; Watanabe, Masayuki; Arai, Tsuyoshi*; Katsuki, Kenta*; Agou, Tomohiro*; Fujikawa, Hisaharu*; Takeda, Keisuke*; Fukumoto, Hiroki*; Hoshina, Hiroyuki*; et al.
Nuclear Instruments and Methods in Physics Research B, 554, p.165448_1 - 165448_10, 2024/09
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Nakahara, Masaumi; Watanabe, So; Ishii, Yasuyuki*; Yamagata, Ryohei*; Yuri, Yosuke*; Yuyama, Takahiro*; Ishizaka, Tomohisa*; Koka, Masashi*; Yamada, Naoto*; Hagura, Naoto*
Nuclear Instruments and Methods in Physics Research B, 554, p.165449_1 - 165449_5, 2024/09
Times Cited Count：0 Percentile：0.00(Instruments & Instrumentation)Ion beam induced luminescence analysis of lanthanide complexes in the organic solvents for minor actinides recovery process was carried out to investigate the structures of complexes. In this study, hydrogen ion beam obtained from the single-ended accelerator and argon ion beam obtained from the azimuthally varying field cyclotron were used in Takasaki Ion Accelerators for Advanced Radiation Application in National Institutes for Quantum Science and Technology. In the experiments, ion beam induced luminescence spectra of lanthanide complexes in the organic solvents were measured, and the relationship between the obtained spectra and the structures of complexes was studied.
Mg, Si, Fe, Cu, and ZnSugihara, Kenta*; Meigo, Shinichiro; Iwamoto, Hiroki; Maekawa, Fujio
Nuclear Instruments and Methods in Physics Research B, 549, p.165299_1 - 165299_12, 2024/04
Times Cited Count：1 Percentile：22.55(Instruments & Instrumentation)
observation of radiation-induced defects in ZrN under electron irradiation in HVEMRahman, M. M.*; Yamamoto, Tomokazu*; Matsumura, Sho*; Takaki, Seiya; Takano, Masahide; Costantini, J. M.*; Yasuda, Kazuhiro*
Nuclear Instruments and Methods in Physics Research B, 549, p.165289_1 - 165289_8, 2024/04
Times Cited Count：6 Percentile：73.07(Instruments & Instrumentation)Nucleation-and-growth process of radiation-induced defects in zirconium nitride (ZrN) has been investigated 
under electron irradiation by using a high voltage transmission electron microscope (HVEM) under electron irradiation by using a high voltage transmission electron microscope (HVEM).
Ogawa, Tatsuhiko; Iwamoto, Yosuke
Nuclear Instruments and Methods in Physics Research B, 549, p.165255_1 - 165255_4, 2024/04
Times Cited Count：2 Percentile：41.12(Instruments & Instrumentation)Atomic defect is one of the critical factors that determines the irradiation effects in materials. The atoms are recoiled by the impulse of incoming radiation, which changes the mechanical, electrical and chemical properties of the target materials. Methods to calculate atomic displacement based on nuclear reaction cross sections and Rutherford scattering cross sections were proposed but they were dedicated to calculation of the defect density in macroscopic scale whereas some phenomena are attributed to the topological arrangements of defects in microscopic scale. Application of a track-structure calculation model, ITSART implemented to a general-purpose radiation transport code PHITS for calculation of the topological arrangement of radiation-induced defects is proposed in this study. To verify the defect production calculated by ITSART, DPA (Displacement Per Atom) cross section in Cu was calculated and compared with literature data. The agreement indicates the accuracy of ITSART for calculating atomic displacement. By using the same methodology to a smaller volume, the defects in SiO exposed to 600 MeV proton beam was calculated. PHITS users can make use of the outputs by forwarding them to other tools, such as molecular dynamics codes, to analyse the further evolution of the defects.
C ions based on first-principles calculationsSekikawa, Takuya; Matsuya, Yusuke; Hwang, B.*; Ishizaka, Masato*; Kawai, Hiroyuki*; Ono, Yoshiaki*; Sato, Tatsuhiko; Kai, Takeshi
Nuclear Instruments and Methods in Physics Research B, 548, p.165231_1 - 165231_6, 2024/03
Times Cited Count：1 Percentile：22.55(Instruments & Instrumentation)One of the main causes of radiation effects on the human body is thought to be damage to DNA, which carries genetic information. However, it is not fully understood what kind of molecular structural changes DNA undergoes upon radiation damage. Since it has been reported that various types of DNA damage are formed when DNA is irradiated, our group has investigated the relationship between DNA damage and various patterns of radiation-induced ionization induced by radiation. Although we have so far analyzed DNA damage in a simple system using a rigid body model of DNA, more detailed calculations are required to analyze the molecular structural changes in DNA, which are considered to be important in considering the effects on the human body. In this study, we attempted to clarify the molecular conformational changes of DNA using OpenMX, a first-principles calculation software that can discuss electronic states based on molecular structures. Specifically, we calculated the most stable structure, band dispersion, and wave function of DNA under the assumption that one and two electrons are ionized by various radiation. In the presentation, we will discuss the relationship between the energy dependence of each incident radiation type and the molecular conformational change of DNA. In addition, the radiation-induced changes in the basic physical properties of DNA (corresponding to the initial stage of DNA damage) will be discussed from the viewpoints of both radiation physics and solid state physics.
