Development of nanosized graphene material for neutron intensity enhancement below cold neutron energy

Teshigawara, Makoto; Ikeda, Yujiro*; Muramatsu, Kazuo*; Sutani, Koichi*; Fukuzumi, Masafumi*; Noda, Yohei*; Koizumi, Satoshi*; Saruta, Koichi; Otake, Yoshie*

Journal of Neutron Research, 26(2-3), p.69 - 74, 2024/09

https://doi.org/10.3233/JNR-240002

Slow neutrons, such as cold neutrons, are important non-destructive probes not only for basic physics but also for the structural genomics advancements in the life sciences and the battery technology advancements needed for the transition to a hydrogen society. Neutron-based science is also known as high-neutron-intensity-dependent science. A new unique method focusing on nanosized particle aggregation has been proposed to increase neutron intensity in that energy region. The method is based on intensity enhancement by multiple coherent scatterings with nanosized particle aggregation. The aggregation of nanosized particles matches the wavelength of below cold neutrons, causing a similar effect to coherent scattering, so-called Bragg scattering, leading to neutron intensity enhancement by several orders of magnitude. Nanodiamonds and magnesium hydride have recently been studied numerically and experimentally. The major challenge with nanodiamonds in practical applications is the molding method. Another carbon structure, graphene is focused on to find a solution to this problem. It is hypothesized that nanosized graphene could aid coherent neutron scattering under particle size conditions similar to nanodiamonds. We report the potential of nanosized graphene as a reflector material below cold neutrons, together with experimental results.

Improvement of neutron diffraction at compact accelerator-driven neutron source RANS using peak profile deconvolution and delayed neutron reduction for stress measurements

Iwamoto, Chihiro*; Takamura, Masato*; Ueno, Kota*; Kataoka, Minami*; Kurihara, Ryo*; Xu, P. G.; Otake, Yoshie*

ISIJ International, 62(5), p.1013 - 1022, 2022/05

https://doi.org/10.2355/isijinternational.ISIJINT-2021-420

Optimization of a slab geometry type cold neutron moderator for RIKEN accelerator-driven compact neutron source

Ma, B.*; Teshigawara, Makoto; Wakabayashi, Yasuo*; Yan, M.*; Hashiguchi, Takao*; Yamagata, Yutaka*; Wang, S.*; Ikeda, Yujiro*; Otake, Yoshie*

Nuclear Instruments and Methods in Physics Research A, 995, p.165079_1 - 165079_7, 2021/04

https://doi.org/10.1016/j.nima.2021.165079

We have optimized a cold neutron moderator to be operated at the RIKEN accelerator-driven compact neutron source. We selected a safe and easy to manage material, mesitylene, as the RANS cold moderator. An efficient moderator system was designed by studying and optimizing a coupled cold neutron moderator of mesitylene at 20 K with a polyethylene (PE) pre-moderator at room temperature in the slab geometry with Particle and Heavy Ion Transport code System (PHITS) simulations. The parameters of mesitylene and PE thickness, the reflector, and the shielding configuration were studied to increase cold neutron intensities. Consequently, an integrated cold neutron intensity of 1.1510n/cm/A at 2 m from the neutron-producing target was finally achieved, which was 12 times higher than that of the current PE moderator. The results showed attractive application prospect of mesitylene as cold neutron moderator material.

Convergence behavior in line profile analysis using convolutional multiple whole-profile software

Kumagai, Masayoshi*; Uchida, Tomohiro*; Murasawa, Kodai*; Takamura, Masato*; Ikeda, Yoshimasa*; Suzuki, Hiroshi; Otake, Yoshie*; Hama, Takayuki*; Suzuki, Shinsuke*

Materials Research Proceedings, Vol.6, p.57 - 62, 2018/10

https://doi.org/10.21741/9781945291890-10

Development of on-site measurement technique of retained austenite volume fraction by compact neutron source RANS

Ikeda, Yoshimasa*; Takamura, Masato*; Hakoyama, Tomoyuki*; Otake, Yoshie*; Kumagai, Masayoshi*; Suzuki, Hiroshi

Tetsu To Hagane, 104(3), p.138 - 144, 2018/03

https://doi.org/10.2355/tetsutohagane.TETSU-2017-080

Neutron engineering diffraction is a powerful technique which provides the information of the micro structure of steels in bulk-average, while X-ray diffraction or Electron backscatter diffraction can provide information only from the surface layer. However, such measurement using neutron diffraction is typically performed in a large facility such as a reactor and a synchrotron, while a compact neutron source has never been used for this purpose. Authors have recently developed a neutron diffractometer installed in Riken Accelerator driven compact Neutron Source (RANS) and succeeded in the measurement of texture evolution of a steel sheet. In this study, we made an attempt to measure the volume fraction of retained austenite by RANS. Background noise was carefully eliminated in order to detect as many diffraction peaks as possible with low flux neutrons. The volume fraction was estimated by Rietveld analysis. The accuracy of the measurement result was discussed by comparing with those obtained by a large neutron facility (J-PARC TAKUMI). The volume fraction obtained by RANS with reasonable measurement time, i.e. 30 to 300 min, showed only 1 to 2 % discrepancies with those obtained in J-PARC. These comparisons suggest that neutron diffraction by RANS is capable of quantitative analysis of the volume fraction of crystal phases, showing the possibility of practical use of an in-house compact neutron source in the industry.

Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

Ikeda, Yoshimasa*; Taketani, Atsushi*; Takamura, Masato*; Sunaga, Hideyuki*; Kumagai, Masayoshi*; Oba, Yojiro*; Otake, Yoshie*; Suzuki, Hiroshi

Nuclear Instruments and Methods in Physics Research A, 833, p.61 - 67, 2016/10

https://doi.org/10.1016/j.nima.2016.06.127

A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by the large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 minutes. The minimum resolution of the 110 reflection for RANS is approximately 2.5 % at 8 s of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 s, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenite phase was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS was proved to be capable for neutron engineering diffraction aiming for the easy access measurement of the texture and the amount of retained austenite.

Non-destructive texture measurement of steel sheets with compact neutron source "RANS"

Takamura, Masato*; Ikeda, Yoshimasa*; Sunaga, Hideyuki*; Taketani, Atsushi*; Otake, Yoshie*; Suzuki, Hiroshi; Kumagai, Masayoshi*; Hama, Takayuki*; Oba, Yojiro*

Journal of Physics; Conference Series, 734(Part B), p.032047_1 - 032047_4, 2016/08

https://doi.org/10.1088/1742-6596/734/3/032047

Neutron diffraction is well known to be a useful technique for measuring a bulk texture of metallic materials taking advantage of a large penetration depth of the neutron beam. However, this technique has not been widely utilized for the texture measurement because large facilities like a reactor or a large accelerator are required in general. In contrast, RANS (Riken Accelerator-driven Compact Neutron Source) has been developed as a neutron source which can be used easily in laboratories. In this study, texture evolution in steel sheets with plastic deformation was successfully measured using RANS. The results show the capability of the compact neutron source for the analysis of the crystal structure of metallic materials, which leads us to a better understanding of plastic deformation behavior.

Design of neutron beamline for fundamental physics at J-PARC BL05

Mishima, Kenji*; Ino, Takashi*; Sakai, Kenji; Shinohara, Takenao; Hirota, Katsuya*; Ikeda, Kazuaki*; Sato, Hiromi*; Otake, Yoshie*; Omori, Hitoshi*; Muto, Suguru*; et al.

Nuclear Instruments and Methods in Physics Research A, 600, p.342 - 345, 2009/02

https://doi.org/10.1016/j.nima.2008.11.087

A new beamline for a fundamental physics experiment is under construction at BL05 port in the Materials and Life Science Facility (MLF) at Japan Proton Accelerator Research Complex (J-PARC), this beamline is designed using novel techniques of neutron optics and it is termed "Neutron Optics and Physics". The beam from the moderator is deflected by multi-channel supermirrors and split into three branches for individual experiments. In this study, we have optimized the design of the beam optics and shields using the Monte Carlo simulation package PHITS. The neutron fluxes of beams are expected to be cmstrsMW, cmsMW, cmsMW, with polarization of 99.8%.

Utilization of compact neutron source at manufacturing sites; Application to metal forming technology

Takamura, Masato*; Iwamoto, Chihiro*; Xu, P. G.; Ueno, Kota*; Kurihara, Ryo*; Suzuki, Hiroshi; Otake, Yoshie*

no journal, , 

Development of neutron reflector material brought about by nano-sized flowers; Intensify neutron beam caused by coherent scattering

Teshigawara, Makoto; Ikeda, Yujiro*; Muramatsu, Kazuo*; Sutani, Koichi*; Fukuzumi, Masafumi*; Noda, Yohei*; Koizumi, Satoshi*; Kawamura, Yuji*; Saruta, Koichi; Otake, Yoshie*

no journal, , 

Science using neutrons in the nanometer (nm) wavelength region as probes is expanding into a wide range of fields, from basic research in materials and life science to industrial applications. Dramatic increase in the intensity of the beam source is required to drive such research. To increase the intensity of neutron beams, we have focused on coherent scattering caused by nano-sized particle aggregations. We focused on graphene, which is different from nanodiamond that has been vigorously researched and developed, and started to develop its nano-sized aggregates, which have high van der Waals force of more than one order of magnitude and stronger bonding force between carbons than nanodiamond, so that they can be easily formed into a lump shape and adapted to higher radiation fields. The graphene is expected to be formable into clumps and adaptable to higher radiation fields. By promoting chemical vapor deposition (CVD), we have established a technique to form nano-sized graphene (graphene flower) with a shape similar to a sunflower flower. In this talk, we report on the neutron scattering characteristics that contribute to the coherent scattering of the newly developed graphene flowers.