Neutron resonance absorption imaging fully utilizing neutron energies from 1 eV to 100 keV

Tsuchikawa, Yusuke; Kai, Tetsuya; Parker, J.*; Matsumoto, Yoshihiro*; Shinohara, Takenao

Scientific Reports (Internet), 15, p.7687_1 - 7687_8, 2025/03

https://doi.org/10.1038/s41598-025-92174-7

A neutron resonance absorption imaging technique to visualize two-dimensional distributions with element discrimination has been developed at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex. We measured neutron transmission spectra from 1 eV to 100 keV while rotating a sample containing iron, zirconium, nickel, molybdenum, and aluminum rods. The distributions of hafnium (impurity of zirconium) and molybdenum were clearly obtained by a straightforward analysis using the most prominent resonances. Then an analysis using multiple resonances of each element simultaneously was performed finding that the accuracy of elemental identification was improved, and iron and nickel distributions became clearer. However, these analysis methods sometimes have difficulties in the case of overlapping materials since a resonance shape can be deteriorated by those of other materials. Such an example was demonstrated with the case of iron and nickel. To overcome the issue and aiming for further improvement, we proposed a method to fit the transmission spectrum in a wide range assuming the existence of possible elements, successfully visualizing both the distributions of the sample metals and those of hafnium and manganese (impurities of zirconium and iron). The newly introduced analysis technique will contribute to the establishment of a standard analytical procedure for general users of the facility.

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

https://doi.org/10.1038/s41598-024-76660-y

We have studied a straightforward and robust single-step cation exchange separation method to isolate medical copper radioisotopes Cu and Cu produced in the 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.

Significant role of secondary electrons in the formation of a multi-body chemical species spur produced by water radiolysis

Kai, Takeshi; Toigawa, Tomohiro; Matsuya, Yusuke*; Hirata, Yuho; Tezuka, Tomoya*; Tsuchida, Hidetsugu*; Yokoya, Akinari*

Scientific Reports (Internet), 14, p.24722_1 - 24722_15, 2024/10

https://doi.org/10.1038/s41598-024-76481-z

Scientific insight of water radiolysis is essential to estimate the direct and indirect effects of radiation DNA damage. Secondary electrons produced by water radiolysis are responsible for both effects. Here, we use a first-principles code to calculate the femtosecond dynamics of secondary electrons produced as a result of 20-30 eV energy deposition to water and analyze the formation mechanism of radiolytic chemical species produced in a nano-size ultra-small space region. From the results, it was clarified that the chemical species produced by water radiolysis begin to densify in the ultra-small region of a few nanometers when the deposition energy exceeds 25 eV. Our results provide important scientific insights into the formation of clustered DNA damage, which is believed to cause biological effects such as cell death.

Demonstration of shape analysis of neutron resonance transmission spectrum measured with a laser-driven neutron source

Koizumi, Mitsuo; Ito, Fumiaki*; Lee, J.; Hironaka, Kota; Takahashi, Tone; Suzuki, Satoshi*; Arikawa, Yasunobu*; Abe, Yuki*; Lan, Z.*; Wei, T.*; et al.

Scientific Reports (Internet), 14, p.21916_1 - 21916_9, 2024/09

https://doi.org/10.1038/s41598-024-72836-8

Cell-cycle dependence on the biological effects of boron neutron capture therapy and its modification by polyvinyl alcohol

Matsuya, Yusuke; Sato, Tatsuhiko; Kusumoto, Tamon*; Yachi, Yoshie*; Seino, Ryosuke*; Miwa, Misako*; Ishikawa, Masayori*; Matsuyama, Shigeo*; Fukunaga, Hisanori*

Scientific Reports (Internet), 14, p.16696_1 - 16696_14, 2024/07

https://doi.org/10.1038/s41598-024-67041-6

Boron neutron capture therapy (BNCT) is a unique radiotherapy to selectively eradicate tumor cells using boron compounds (e.g., 4-borono-L-phenylalanine [BPA]) that are heterogeneously taken up at the cellular level. However, the impacts of tempo-spatial heterogenicity on cell killing remain unclear. With the technical combination of radiation track detector, cell cycle analysis, and biophysical simulations, we demonstrated the cell cycle-dependent heterogenicity of BPA uptake and following biological impacts of B(n, )Li reactions in HeLa cells expressing Fluorescent Ubiquitination-based Cell Cycle Indicators (FUCCI), as well as its modification effects of polyvinyl alcohol (PVA). As a result, we revealed that the intracellular BPA concentration in the S/G2/M phase was higher than that in the G1/S phase and that PVA modified the cell cycle dependence. Further, these findings lead to the development of the first BPA-PVA-based model for predicting BNCT treatment effects. These outcomes may contribute to more precision of therapeutic efficacy, when BNCT is combined with PVA and/or cell cycle-specific anticancer agents.

The Impact of dose rate on responses of human lens epithelial cells to ionizing irradiation

Matsuya, Yusuke; Sato, Tatsuhiko; Yachi, Yoshie*; Date, Hiroyuki*; Hamada, Nobuyuki*

Scientific Reports (Internet), 14, p.12160_1 - 12160_14, 2024/05

https://doi.org/10.1038/s41598-024-62679-8

Understand mechanisms of radiation cataracts that are of concern in the field of radiation protection and radiation therapy. However, biological effects in HLEC following protracted exposure have not yet fully been explored. Here, we investigated the temporal kinetics of DNA double-strand breaks (DSBs) and cell survival of HLEC after exposure to photon beams at various dose rates, compared to those of human lung fibroblasts (WI-38). In parallel, we quantified the recovery for DSB and cell survival using a biophysical model. The study revealed that HLEC cells have a lower repair rate than WI-38 cells. There is no significant impact of dose rate on cell survival in both cell lines in the dose-rate range of 0.033-1.82 Gy/min. On the other hand, the experimental residual DSBs showed inverse dose rate effects (IDREs) compared to the model prediction, highlighting the importance of the IDREs in evaluating radiation effects on the ocular lens.

Laser-based angle-resolved photoemission spectroscopy with micrometer spatial resolution and detection of three-dimensional spin vector

Iwata, Takuma*; Kosa, Towa*; Nishioka, Yukimi*; Owada, Kiyotaka*; Sumida, Kazuki; Annese, E.*; Kakoki, Masaaki*; Kuroda, Kenta*; Iwasawa, Hideaki*; Arita, Masashi*; et al.

Scientific Reports (Internet), 14, p.127_1 - 127_8, 2024/01

https://doi.org/10.1038/s41598-023-47719-z

In situ neutron imaging of lithium-ion batteries during heating to thermal runaway

Nozaki, Hiroshi*; Kondo, Hiroki*; Shinohara, Takenao; Setoyama, Daigo*; Matsumoto, Yoshihiro*; Sasaki, Tsuyoshi*; Isegawa, Kazuhisa*; Hayashida, Hirotoshi*

Scientific Reports (Internet), 13, p.22082_1 - 22082_8, 2023/12

https://doi.org/10.1038/s41598-023-49399-1

Influence of the strain effect on magnetocrystalline anisotropy in CoFeMnSi Heusler alloys

Nabialek, A.*; Chumak, O. M.*; Aleshkevych, P.*; Domagala, J. Z.*; Pacewicz, A.*; Salski, B.*; Krupka, J.*; Seki, Takeshi*; Takanashi, Koki; Baczewski, L. T.*; et al.

Scientific Reports (Internet), 13, p.17016_1 - 170169, 2023/10

https://doi.org/10.1038/s41598-023-43979-x

Atomic reconstruction induced by uniaxial stress in MnP

Kozawa, Tatsuya*; Fujihara, Masayoshi; Uchihara, Takeru*; Mitsuda, Setsuo*; Yano, Shinichiro*; Tamatsukuri, Hiromu; Munakata, Koji*; Nakao, Akiko*

Scientific Reports (Internet), 13, p.13750_1 - 13750_8, 2023/08

https://doi.org/10.1038/s41598-023-40806-1

In condensed matter physics, pressure is frequently used to modify the stability of both electronic states and atomic arrangements. Under isotropic pressure, the intermetallic compound MnP has recently attracted attention for the interplay between pressure-induced superconductivity and complicated magnetic order in the vicinity. By contrast, we use uniaxial stress, a directional type of pressure, to investigate the effect on the magnetism and crystal structure of this compound. An irreversible magnetisation response induced by uniaxial stress is discovered in MnP at uniaxial stress as low as 0.04 GPa. Neutron diffraction experiments reveal that uniaxial stress forms crystal domains that satisfy pseudo-rotational symmetry unique to the MnP-type structure. The structure of the coexisting domains accounts for the stress-induced magnetism. We term this first discovered phenomenon atomic reconstruction (AR) induced by uniaxial stress. Furthermore, our calculation results provide guidelines on the search for AR candidates. AR allows crystal domain engineering to control anisotropic properties of materials, including dielectricity, elasticity, electrical conduction, magnetism and superconductivity. A wide-ranging exploration of potential AR candidates would ensure that crystal domain engineering yields unconventional methods to design functional multi-domain materials for a wide variety of purposes.