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Journal Articles

Development and application of a $$^3$$He neutron spin filter at J-PARC

Okudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10

 Times Cited Count:3 Percentile:78.97(Instruments & Instrumentation)

Journal Articles

In-house texture measurement using a compact neutron source

Xu, P. G.; Ikeda, Yoshimasa*; Hakoyama, Tomoyuki*; Takamura, Masato*; Otake, Yoshie*; Suzuki, Hiroshi

Journal of Applied Crystallography, 53(2), p.444 - 454, 2020/04

AA2019-0242.pdf:2.9MB

 Times Cited Count:1 Percentile:39.63(Chemistry, Multidisciplinary)

Journal Articles

Electronic structure of the high-$$T_{rm C}$$ ferromagnetic semiconductor (Ga,Fe)Sb; X-ray magnetic circular dichroism and resonance photoemission spectroscopy studies

Sakamoto, Shoya*; Tu, N. T.*; Takeda, Yukiharu; Fujimori, Shinichi; Hai, P. N.*; Anh, L. D.*; Wakabayashi, Yuki K.*; Shibata, Goro*; Horio, Masafumi*; Ikeda, Keisuke*; et al.

Physical Review B, 100(3), p.035204_1 - 035204_8, 2019/07

Journal Articles

Electronic structure of the high-$$T_{rm C}$$ ferromagnetic semiconductor (Ga,Fe)Sb; X-ray magnetic circular dichroism and resonance photoemission spectroscopy studies

Sakamoto, Shoya*; Tu, N. T.*; Takeda, Yukiharu; Fujimori, Shinichi; Hai, P. N.*; Anh, L. D.*; Wakabayashi, Yuki*; Shibata, Goro*; Horio, Masafumi*; Ikeda, Keisuke*; et al.

Physical Review B, 100(3), p.035204_1 - 035204_8, 2019/07

 Times Cited Count:8 Percentile:69.34(Materials Science, Multidisciplinary)

Journal Articles

Local magnetic states of the weakly ferromagnetic iron-based superconductor Sr$$_{2}$$VFeAsO$$_{3-delta}$$ studied by X-ray magnetic circular dichroism

Horio, Masafumi*; Takeda, Yukiharu; Namiki, Hiromasa*; Katagiri, Takao*; Wakabayashi, Yuki*; Sakamoto, Shoya*; Nonaka, Yosuke*; Shibata, Goro*; Ikeda, Keisuke*; Saito, Yuji; et al.

Journal of the Physical Society of Japan, 87(10), p.105001_1 - 105001_2, 2018/10

 Times Cited Count:1 Percentile:17.19(Physics, Multidisciplinary)

Journal Articles

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

 Times Cited Count:0 Percentile:0.2

Journal Articles

Nanoscale ice-type structural fluctuation in spinel titanates

Torigoe, Shuhei*; Hattori, Takayuki*; Kodama, Katsuaki; Honda, Takashi*; Sagayama, Hajime*; Ikeda, Kazutaka*; Otomo, Toshiya*; Nitani, Hiroaki*; Abe, Hitoshi*; Murakawa, Hiroshi*; et al.

Physical Review B, 98(13), p.134443_1 - 134443_7, 2018/10

 Times Cited Count:2 Percentile:17.02(Materials Science, Multidisciplinary)

Journal Articles

Cation distribution and magnetic properties in ultrathin (Ni$$_{1-x}$$Co$$_{x}$$)Fe$$_{2}$$O$$_{4}$$ (x=0-1) layers on Si(111) studied by soft X-ray magnetic circular dichroism

Wakabayashi, Yuki*; Nonaka, Yosuke*; Takeda, Yukiharu; Sakamoto, Shoya*; Ikeda, Keisuke*; Chi, Z.*; Shibata, Goro*; Tanaka, Arata*; Saito, Yuji; Yamagami, Hiroshi; et al.

Physical Review Materials (Internet), 2(10), p.104416_1 - 104416_12, 2018/10

 Times Cited Count:6 Percentile:38.74(Materials Science, Multidisciplinary)

Journal Articles

Determination approach of dislocation density and crystallite size using a convolutional multiple whole profile software

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

Materials Transactions, 59(7), p.1135 - 1141, 2018/07

 Times Cited Count:1 Percentile:44.01(Materials Science, Multidisciplinary)

Journal Articles

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

 Times Cited Count:1 Percentile:10.68(Metallurgy & Metallurgical Engineering)

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.

Journal Articles

Implementation of a low-activation Au-In-Cd decoupler into the J-PARC 1 MW short pulsed spallation neutron source

Teshigawara, Makoto; Ikeda, Yujiro; Oi, Motoki; Harada, Masahide; Takada, Hiroshi; Kakishiro, Masanori*; Noguchi, Gaku*; Shimada, Tsubasa*; Seita, Kyoichi*; Murashima, Daisuke*; et al.

Nuclear Materials and Energy (Internet), 14, p.14 - 21, 2018/01

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

We developed an Au-In-Cd (AuIC) decoupler material to reduce induced radioactivity instead of Ag-In-Cd one, which has a cut off energy of 1eV. In order to implement it into an actual moderator-reflector assembly, a number of critical engineering issues need to be resolved with regard to large-sized bonding between AuIC and A5083 alloys by the hot isostatic pressing process. We investigated this process in terms of the surface conditions, sizes, and heat capacities of large AuIC alloys. We also show a successful implementation of an AuIC decoupler into a reflector assembly, resulting in a remarkable reduction of radioactivity by AuIC compared to AIC without sacrificing neutronic performance.

JAEA Reports

Investigation and measures of abnormal events of helium refrigerator for cryogenic hydrogen system at J-PARC

Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Aoyagi, Katsuhiro*; Muto, Hideki*; Nomura, Kazutaka*; Takada, Hiroshi; Ikeda, Yujiro

JAEA-Technology 2017-021, 75 Pages, 2017/08

JAEA-Technology-2017-021.pdf:33.03MB

Liquid hydrogen is employed as a cold neutron moderator material at the spallation neutron source of Materials and Life science experimental Facility of Japan Proton Accelerator Research Complex (J-PARC). From January 2015, it became observable that the differential pressure between heat exchangers and an 80 K adsorber (ADS) in a helium refrigerator system increased with operating time. In November 2015, the differential pressure rise became more significant, leading to degrade the refrigerating performance in cooling liquid hydrogen. In order to investigate the cause of the abnormal differential pressure rise between the heat exchangers and the ADS, we carried out visual inspection inside the heat exchangers and analyzed the impurities contained in the helium gas. Unfortunately, we could not identify the impurities causing the performance degradation, but observed a trace of oil in the inlet piping of the heat exchanger. Based on investigations of the abnormal events occurred in the refrigerators with similar refrigerating capacity at other facilities, we took measures that cleaning the heat exchangers with Freon and replacing the ADS with new one. As a result, the differential pressure rise phenomenon was removed to recover the performance. We have detected oil from the Freon used for cleaning the heat exchangers and at a felt supporting charcoal packed in the ADS. In particular, oil was accumulated in membranous form onto the felt at the entrance side in the ADS. The amount of oil contained in the helium gas was about 10 ppb or so, less than the design value, in the helium refrigerator. However, the oil accumulated onto the felt in the ADS through long operating period may cause abnormal differential pressure rise, leading to the performance degradation of the helium refrigerator. Further study is needed to specify the cause more clearly.

Journal Articles

Updating HBase/Hadoop in the J-PARC operation data archiver with making the data collection tool redundant by ZooKeeper

Ikeda, Hiroshi; Kikuzawa, Nobuhiro; Yoshii, Akinobu*; Kato, Yuko

Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.637 - 640, 2016/11

no abstracts in English

Journal Articles

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

 Times Cited Count:28 Percentile:97.18(Instruments & Instrumentation)

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 $$mu$$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 $$mu$$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.

Journal Articles

Texture evaluation in ductile fracture process by neutron diffraction measurement

Sunaga, Hideyuki*; Takamura, Masato*; Ikeda, Yoshimasa*; Otake, Yoshie*; Hama, Takayuki*; Kumagai, Masayoshi*; Suzuki, Hiroshi; Suzuki, Shinsuke*

Journal of Physics; Conference Series, 734(Part B), p.032027_1 - 032027_4, 2016/09

 Times Cited Count:0 Percentile:0.03

A neutron diffraction measurement was performed to reveal microstructural aspects of the ductile fracture in ferritic steel. The diffraction patterns were continuously measured at the center of the reduced area while a tensile specimen was loaded under tension until the end of the fracture process. The measurement results showed that the volume fraction of (110)-oriented grains increased when the texture evolved as a result of plastic deformation. But the mechanism of texture evolution may be changed during necking, decreasing an increase rate of the volume fraction.

Journal Articles

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

 Times Cited Count:4 Percentile:81.81

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.

Journal Articles

Observation of all-in type tetrahedral displacements in nonmagnetic pyrochlore niobates

Torigoe, Shuhei*; Ishimoto, Yutaro*; Aoishi, Yuhei*; Murakawa, Hiroshi*; Matsumura, Daiju; Yoshii, Kenji; Yoneda, Yasuhiro; Nishihata, Yasuo; Kodama, Katsuaki; Tomiyasu, Keisuke*; et al.

Physical Review B, 93(8), p.085109_1 - 085109_5, 2016/02

 Times Cited Count:4 Percentile:27.06(Materials Science, Multidisciplinary)

Journal Articles

Development of the J-PARC time-series data archiver using a distributed database system, 2

Kikuzawa, Nobuhiro; Ikeda, Hiroshi; Kato, Yuko; Yoshii, Akinobu*

Proceedings of 15th International Conference on Accelerator and Large Experimental Physics Control Systems (ICALEPCS 2015) (Internet), p.818 - 821, 2016/00

J-PARC (Japan Proton Accelerator Research Complex) consists of much equipment. In Linac and 3 GeV rapid cycling synchrotron ring (RCS), the data of over the 64,000 EPICS records for these equipment has been collected. The Data volume will be about 10 TB in 2020. The data have been being stored by a Relational Data Base (RDB) system using PostgreSQL, but it is not enough in availability, performance, and capability to increase of data volume flexibility. Hadoop/HBase, which is known as a distributed, scalable and big data store, has been proposed for our next-generation archive system to solve these problems. The archiving system was built and verified about data transition or database utilization. This report shows the result of the modification of the archive system.

Journal Articles

Neutron diffraction of ice and water in hydrogels

Sekine, Yurina; Kobayashi, Riki*; Chi, S.*; Fernandez-Baca, J. A.*; Suzuya, Kentaro; Fujisaki, Fumika*; Ikeda, Kazutaka*; Otomo, Toshiya*; Fukazawa, Tomoko*; Yamauchi, Hiroki; et al.

JPS Conference Proceedings (Internet), 8, p.033009_1 - 033009_6, 2015/09

Neutron diffraction profiles of low-D$$_{2}$$O-content poly-N,N,-dimethylacrylamide (PDMAA) hydrogels were measured from 100 to 300 K to investigate the structure and properties of water in hydrogels. A broad diffraction observed at temperatures lower than 220 K indicates the existence of amorphous ice in the hydrogels at low temperatures. During the heating process, diffraction peaks from ice crystals appear in the profiles. These peaks indicate that cubic ice and hexagonal ice exist at T $$geq$$ 220 K. We refined the structure parameters of these ices in the hydrogel, which indicate the existence of low-density ice in the hydrogel.

Journal Articles

Improvement of the J-PARC operation data archiver using HBase/Hadoop

Ikeda, Hiroshi; Kikuzawa, Nobuhiro; Yoshii, Akinobu*; Kato, Yuko

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1312 - 1316, 2015/09

The Linac and the RCS in J-PARC provide enormous operation data and we have been stored them into PostgreSQL. We are planning to replace it with HBase, a data store specialized for big-data and is on a distributed file system provided by Hadoop, using a cluster with advantages including automatically recovering and easily extending the capacity. In the previous presentation we reported we updated HBase/Hadoop in our test system and we showed issues to fix our tools in the new system, while we also mentioned issues about the construction of our cluster itself. In this presentation we are reporting we have re-designed and re-constructed the cluster with resolving the issues, including enhancing hardware of master nodes, creating automatic scripts to construct nodes, and introducing monitoring tools for nodes. Having accordingly adjusted the configurations of HBase/Hadoop and measured the performance of our new system, we are also reporting its results and considerations.

303 (Records 1-20 displayed on this page)