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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
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.
Teshigawara, Makoto; Ikeda, Yujiro*; Yan, M.*; Muramatsu, Kazuo*; Sutani, Koichi*; Fukuzumi, Masafumi*; Noda, Yohei*; Koizumi, Satoshi*; Saruta, Koichi; Otake, Yoshie*
Nanomaterials (Internet), 13(1), p.76_1 - 76_9, 2023/01
Times Cited Count:4 Percentile:60.72(Chemistry, Multidisciplinary)To enhance neutron intensity below cold neutrons, it is proposed that nanosized graphene aggregation could facilitate neutron coherent scattering under particle size conditions similar to nanodiamond. It might also be possible to use it in high neutron radiation conditions due to graphene's strong sp2 bonds. Using the RIKEN accelerator-driven compact neutron source and iMATERIA at J-PARC, we performed neutron measurement experiments, total neutron cross-section, and small-angle neutron scattering on nanosized graphene aggregation. The measured data revealed, for the first time, that nanosized graphene aggregation increased the total cross-sections and small-angle scattering in the cold neutron energy region, most likely due to coherent scattering, resulting in higher neutron intensities, similar to nanodiamond.
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.
Muramatsu, Kazuo*; Sutani, Koichi*; Kimishima, Koichi*; Teshigawara, Makoto; Ikeda, Yujiro*; Fukuzumi, Masafumi*; Koizumi, Satoshi*; Kawamura, Yuji*; Saruta, Koichi; Otake, Yoshie*
no journal, ,
The use of nano-diamonds has been vigorously investigated to increase the intensity of neutron beams, focusing on the coherent scattering caused by nano-sized particle aggregations. Sp2 intercarbon-bonded graphene has a larger van der Waals force than sp3 intercarbon-bonded nano-diamonds. It is expected to be more easily formed into a lump shape and adaptability to higher radiation fields. On the other hand, the large cohesive nature of graphene makes it difficult to construct nano-sized three-dimensional structures. To solve this problem, we focused on the Hot Isostatic Pressing (HIP) method, which uses resin powder as a raw material and produces vapor-phase grown graphene. In this talk, we will report on the preparation of graphene flower structures, in which nano-sized graphene is three-dimensionally freestanding, how to control the nano-size of graphene, and a prototype of graphene neutron reflector material.