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
Tang, T. L.*; Uesaka, Tomohiro*; Kawase, Shoichiro; Beaumel, D.*; Dozono, Masanori*; Fujii, Toshihiko*; Fukuda, Naoki*; Fukunaga, Taku*; Galindo-Uribarri. A.*; Hwang, S. H.*; et al.
Physical Review Letters, 124(21), p.212502_1 - 212502_6, 2020/05
The structure of a neutron-rich F nucleus is investigated by a quasifree () knockout reaction. The sum of spectroscopic factors of orbital is found to be 1.0 0.3. The result shows that the O core of F nucleus significantly differs from a free O nucleus, and the core consists of 35% O, and 65% excited O. The result shows that the O core of F nucleus significantly differs from a free O nucleus. The result may infer that the addition of the proton considerably changes the neutron structure in F from that in O, which could be a possible mechanism responsible for the oxygen dripline anomaly.
Tamura, Jun; Kondo, Yasuhiro; Yee-Rendon, B.; Meigo, Shinichiro; Maekawa, Fujio; Hasegawa, Kazuo; Kako, Eiji*; Umemori, Kensei*; Sakai, Hiroshi*; Konomi, Taro*
Proceedings of 19th International Conference on RF Superconductivity (SRF 2019) (Internet), p.399 - 402, 2019/11
Sakai, Kenji; Oi, Motoki; Takada, Hiroshi; Kai, Tetsuya; Nakatani, Takeshi; Kobayashi, Yasuo*; Watanabe, Akihiko*
JAEA-Technology 2018-011, 57 Pages, 2019/01
For safely and efficiently operating a spallation neutron source and a muon target, a general control system (GCS) operates within Materials and Life Science Experimental Facility (MLF). GCS administers operation processes and interlocks of many instruments. It consists of several subsystems such as an integral control system (ICS), interlock systems (ILS), shared servers, network system, and timing distribution system (TDS). Although GCS is an independent system that controls the target stations, it works closely with the control systems of the accelerators and other facilities in J-PARC. Since the first beam injection, GCS has operated stably without any serious troubles after modification based on commissioning for operation and control. Then, significant improvements in GCS such as upgrade of ICS by changing its framework software and function enhancement of ILS were proceeded until 2015. In this way, many modifications have been proceeded in the entire GCS during a period of approximately ten years after start of beam operation. Under these situation, it is important to comprehend upgrade history and present status of GCS in order to decide its upgrade plan. This report summarizes outline, structure, roles and functions of GCS in 2017.
Dioguardi, A. P.*; Yasuoka, Hiroshi*; Thomas, S. M.*; Sakai, Hironori; Cary, S. K.*; Kozimor, S. A.*; Albrecht-Schmitt, T. E.*; Choi, H. C.*; Zhu, J.-X.*; Thompson, J. D.*; et al.
Physical Review B, 99(3), p.035104_1 - 035104_6, 2019/01
We present a detailed nuclear magnetic resonance (NMR) study of Pu in bulk and powdered single-crystal plutonium tetraboride (PuB), which has recently been investigated as a potential correlated topological insulator. The Pu NMR spectra are consistent with axial symmetry of the shift tensor showing for the first time that Pu NMR can be observed in an anisotropic environment and up to room temperature. The temperature dependence of the Pu shift, combined with a relatively long spin-lattice relaxation time (), indicate that PuB adopts a nonmagnetic state with gaplike behavior consistent with our density functional theory calculations. The temperature dependencies of the NMR Knight shift and imply bulk gaplike behavior confirming that PuB is a good candidate topological insulator.
Sakai, Takuro; Iikura, Hiroshi; Yamada, Naoto*; Sato, Takahiro*; Ishii, Yasuyuki*; Uchida, Masaya*
QST-M-8; QST Takasaki Annual Report 2016, P. 140, 2018/03
Kawamura, Seiko; Oku, Takayuki; Watanabe, Masao; Takahashi, Ryuta; Munakata, Koji*; Takata, Shinichi; Sakaguchi, Yoshifumi*; Ishikado, Motoyuki*; Ouchi, Keiichi*; Hattori, Takanori; et al.
Journal of Neutron Research, 19(1-2), p.15 - 22, 2017/11
Sample environment (SE) team at the Materials and Life Science Experimental Facility (MLF) in J-PARC has worked on development and operation of SE equipment and devices. All the members belong to one sub-team at least, such as Cryogenic and magnet, High temperature, High pressure, Soft matter and special environment including Pulse magnet, Hydrogen environment, Light irradiation and He spin filter. Cryostats, a magnet, furnaces, a VX-6-type Paris-Edinburgh press and a prototype of a Spin-Exchange Optical Pumping (SEOP) based He spin filter for polarized neutron beam experiments are in operation. Furthermore, a prototype of compact power supply for a pulsed magnet system is currently developed. In the J-PARC Research Building, several pieces of equipment for softmatter research such as a rheometer and a gas and vapor adsorption measurement instrument have been prepared.
Sakasai, Kaoru; Sato, Setsuo*; Seya, Tomohiro*; Nakamura, Tatsuya; To, Kentaro; Yamagishi, Hideshi*; Soyama, Kazuhiko; Yamazaki, Dai; Maruyama, Ryuji; Oku, Takayuki; et al.
Quantum Beam Science (Internet), 1(2), p.10_1 - 10_35, 2017/09
Neutron devices such as neutron detectors, optical devices including supermirror devices and He neutron spin filters, and choppers are successfully developed and installed at the Materials Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Four software components of MLF computational environment, instrument control, data acquisition, data analysis, and a database, have been developed and equipped at MLF. MLF also provides a wide variety of sample environment options including high and low temperatures, high magnetic fields, and high pressures. This paper describes the current status of neutron devices, computational and sample environments at MLF.
Tsuji, Tomoyuki; Hoshino, Yuzuru; Sakai, Akihiro; Sakamoto, Yoshiaki; Suzuki, Yasuo*; Machida, Hiroshi*
JAEA-Technology 2017-010, 75 Pages, 2017/06
It is necessary for reasonable disposal to be studied on evaluation methods to determine radioactivity concentrations in the radioactive wastes, which is generated from post-irradiation examination (PIE) facilities, for establishment of reasonable confirmation methods concerning radioactive wastes generated from research, industrial, and medical facilities. It has been chosen the PIE facilities of NUCLEAR DEVELOPMENT CORPORATION as a model for this study. As a result, it has been confirmed that the theoretical methods are applied for the important nuclides (H-3, C-14, Co-60, Ni-63, Sr-90, Tc-99, Cs-137, Eu-154, U-234, U-235, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Am-241 and Cm-244).
Sakai, Hironori; Ronning, F.*; Hattori, Takanori; Tokunaga, Yo; Kambe, Shinsaku; Zhu, J.-X.*; Wakeham, N.*; Yasuoka, Hiroshi; Bauer, E. D.*; Thompson, J. D.*
Journal of Physics; Conference Series, 807(3), p.032001_1 - 032001_6, 2017/04
We have used nuclear quadrupole resonance (NQR) to probe microscopically the response of a prototypical quantum critical metal CeCoIn to substitutions of small amounts of Cd for In. Approximately half of the Cd substituents induce local Ce moments in their close proximity, as observed by site-dependent longitudinal nuclear spin relaxation rates . To reaffirm that localized moments are induced around the Cd substituents, we find a Gaussian spin-echo decay rate of transverse nuclear spin relaxation. Further, for the NQR subpeak is found to be proportional to temperatures, again indicating local moments fluctuations around the Cd substituents, while that for the NQR main peak shows a -dependence. The latter temperature dependence is close to 0.75 in pure CeCoIn and indicates that the bulk electronic state is located close to a two dimensional quantum critical instability.
Sakai, Takuro; Yasuda, Ryo; Iikura, Hiroshi; Matsubayashi, Masahito
JPS Conference Proceedings (Internet), 11, p.020005_1 - 020005_6, 2016/11
Sakai, Kenji; Oi, Motoki; Watanabe, Akihiko; Kai, Tetsuya; Kato, Yuko; Meigo, Shinichiro; Takada, Hiroshi
JAEA-Conf 2015-002, p.593 - 598, 2016/02
For safe and stable beam operation, a MLF general control system (GCS) consists of several subsystems such as an integral control, interlock, server, network, and timing distribution systems. Since the first beam injection in 2008, the GCS has operated stably without any serious troubles in comparison with upgrade of target devices for ramping up beam power and increment of user apparatuses year by year. In recent years, however, it has been improved significantly in view of sustainable long-term operation and maintenance. The monitor and operation system of the GCS has been upgraded by changing its framework software to improve potential flexibility in its maintenance. Its interlock system was also modified in accordance with the re-examination of the risk management system of J-PARC. This paper reports recent progress of the MLF-GCS.
Sakai, Hiroshi*; Enami, Kazuhiro*; Furuya, Takaaki*; Kako, Eiji*; Kondo, Yoshinari*; Michizono, Shinichiro*; Miura, Takako*; Qiu, F.*; Sato, Masato*; Shinoe, Kenji*; et al.
Proceedings of 56th ICFA Advanced Beam Dynamics Workshop on Energy Recovery Linacs (ERL 2015) (Internet), p.63 - 66, 2015/12
no abstracts in English
Iikura, Hiroshi; Sakai, Takuro; Matsubayashi, Masahito
Hamon, 25(4), p.277 - 282, 2015/11
We introduce the basic principle of neutron radiography technique, and the brief review of its applications. Most of works in this article have been performed at TNRF, Tokai, Japan. Neutron radiography is a nondestructive testing method, so that this technique is used for not only academic studies but also industrial applications. Keywords: neutron radiography, imaging, TNRF
Faenov, A.*; Matsubayashi, Masahito; Pikuz, T.*; Fukuda, Yuji; Kando, Masaki; Yasuda, Ryo; Iikura, Hiroshi; Nojima, Takehiro; Sakai, Takuro; Shiozawa, Masahiro*; et al.
High Power Laser Science and Engineering, 3, p.e27_1 - e27_9, 2015/10
Oi, Motoki; Sakai, Kenji; Watanabe, Akihiko; Akutsu, Atsushi; Meigo, Shinichiro; Takada, Hiroshi
JPS Conference Proceedings (Internet), 8, p.036007_1 - 036007_5, 2015/09
This paper reports on upgrading of the monitor and operation (MO) system for a general control system (GCS) of the Materials and Life science experimental Facility (MLF) at J-PARC. The MLF-GCS consists of programmable logic controllers (PLCs), operator interfaces (OPIs) for integral control and interlock systems, shared servers, and so on. It is controlling various components of the pulsed spallation neutron source such as a mercury target and hydrogen moderators. The MO system is used for monitoring, alarm notification and remote control from the MLF control room. The GCS has been working well as expected, but current MO system which consists of the OPIs and data servers based on iFix has some problems in view of sustainable maintenance because of its poor flexibility of supported OS and software version compatibility. To overcome the problems, we upgraded the MO system to be operated using the framework of EPICS, the OPI of Control System Studio (CSS) and the server software of Postgre SQL. This improves versatility of the MO system, enabling to run on various platforms such as Windows, Linux and Mac OS. At first, we made a prototype MO system, which processed 100 points of data and 5 operation screens and verified that the MO system functions correctly. Then we made full spec MO system which processes the data point of 7000 and operation screens of 130. It was operated in parallel with the current system to evaluate its performance with real data such as data transmission speed from PLCs, control functions from OPI, storage capability of servers and long-term reliability. As results, the new MO system achieved the communication speed of 2 Hz and its operability compatible to the current system. Now, we are operating and debugging it in comparison with the current system during the operating period as a preparation for the system replacement at the end of 2014.
Sakai, Kenji; Oku, Takayuki; Hayashida, Hirotoshi*; Kira, Hiroshi*; Hiroi, Kosuke; Ino, Takashi*; Oyama, Kenji*; Okawara, Manabu*; Kakurai, Kazuhisa; Shinohara, Takenao; et al.
JPS Conference Proceedings (Internet), 8, p.036015_1 - 036015_6, 2015/09
The polarized He filter, which polarizes neutrons due to a large neutron absorption cross section of He with strong spin selectivity, becomes a convenient neutron spin filter (NSF) because it is operated immediately after its installation in beam lines without any neutron beam adjustments. For realizing such the NSF, a nuclear magnetic resonance (NMR) system is indispensable for monitoring He nuclear spin polarization of the NSF. We have developed the flexible NMR system based on adiabatic fast passage (AFP) and pulse NMR methods by using their complementary features. In comparing with the values of obtained by neutron transmission measurement at the beam line 10 of the J-PARC, we measured the correlations between the AFP and pulse NMR signals as changing condition of temperature, amplitude and applying period of the radio frequency field for the pulse NMR, and so on. As the results, we confirmed that our system would function enough as the monitor.
Sakai, Hironori; Ronning, F.*; Zhu, J.-X.*; Wakeham, N.*; Yasuoka, Hiroshi; Tokunaga, Yo; Kambe, Shinsaku; Bauer, E. D.*; Thompson, J. D.*
Physical Review B, 92(12), p.121105_1 - 121105_5, 2015/09
Chemical substitutions are used commonly to tune a magnetic transition to zero temperature, but the resulting non-Fermi liquid (NFL) behavior is non-universal. We have used nuclear quadrupole resonance (NQR) to probe microscopically the response of a prototypical quantum-critical metal CeCoIn to substitutions of small amounts of Sn and Cd for In. These substituents induce very different local electronic environments as observed by site dependent spin lattice relaxation rates that influence the NFL behavior. The effects found here illustrate the need for care in interpreting NFL properties determined by macroscopic measurements.
Sawamura, Masaru; Umemori, Kensei*; Sakai, Hiroshi*; Shinoe, Kenji*; Furuya, Takaaki*; Enami, Kazuhiro*; Egi, Masato*
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.579 - 582, 2015/09
no abstracts in English
Shinoe, Kenji*; Sakai, Hiroshi*; Umemori, Kensei*; Enami, Kazuhiro*; Sawamura, Masaru; Egi, Masato*; Furuya, Takaaki*
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.548 - 552, 2015/09
no abstracts in English