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rays in the 
La(
)
La
reactionOkudaira, Takuya*; Endo, Shunsuke; Fujioka, Hiroyuki*; Hirota, Katsuya*; Ishizaki, Kohei*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; Ninomi, Yudai*; Sakai, Kenji; et al.
Physical Review C, 104(1), p.014601_1 - 014601_6, 2021/07
Times Cited Count：0 Percentile：0.03(Physics, Nuclear)Sakai, Kenji; Oi, Motoki; Haga, Katsuhiro; Kai, Tetsuya; Nakatani, Takeshi; Kobayashi, Yasuo*; Watanabe, Akihiko*
JPS Conference Proceedings (Internet), 33, p.011151_1 - 011151_6, 2021/03
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 for various operation statuses. 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 other facilities in J-PARC. Since the first beam injection in 2008, 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 considering sustainable long-term operation and maintenance. In recent years, many instruments in GCS have replaced due to end of production and support of them. In this way, many modifications have been proceeded in the entire GCS 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 for the coming ten years. This report will mention upgrade history, present status and future agenda of GCS.
Sakai, Kenji; Oku, Takayuki; Okudaira, Takuya; Kai, Tetsuya; Harada, Masahide; Hiroi, Kosuke; Hayashida, Hirotoshi*; Kakurai, Kazuhisa*; Shimizu, Hirohiko*; Hirota, Katsuya*; et al.
JPS Conference Proceedings (Internet), 33, p.011116_1 - 011116_6, 2021/03
In neutron fundamental physics, study of correlation term 
of a neutron spin 
and a target nuclear spin 
is important because term interferes to parity non-conserving (PNC) and time reversal non-conserving terms. For this study, a xenon (Xe) is an interesting nucleus because it has been observed an enhancement of PNC effect around neutron resonance peaks, and polarizes up to 
by using a spin exchange optical pumping (SEOP) method. We would plan to develop a polarized Xe gas target with a compact in-situ SEOP system, and to study term by utilizing epithermal neutron beams supplied from a high intense pulsed spallation neutron source. As the first step, we attempted to measure neutron polarizing ability caused by term at a 9.6 eV s-wave resonance peak of 
Xe at BL10 in MLF, by detecting change 
of ratio between neutron transmissions with the polarized and unpolarized Xe target. After demonstrating that our apparatus could detect small change (
) of neutron transmissions caused by Doppler broadening effect, a signified value of has been obtained as preliminary results. For analyzing the obtained in detail, we are improving our nuclear magnetic resonance and electron paramagnetic resonance systems for evaluating Xe polarization independently of neutron beams.
Sakai, Kenji; Oi, Motoki; Teshigawara, Makoto; Naoe, Takashi; Haga, Katsuhiro; Watanabe, Akihiko*
Journal of Neutron Research, 22(2-3), p.337 - 343, 2020/10
For operating a spallation neutron source and a muon target safely and efficiently, a general control system (GCS) operates within Materials and Life Science Experimental Facility (MLF). GCS administers operation and interlock processes of many instruments under various operation status. Since the first beam injection in 2008, it has operated stably without any serious troubles for more than ten years. GCS has a data storage server storing operational data on status around target stations. It has functioned well to detect and investigate unusual situations by checking data in this server. For continuing stable operation of MLF in future, however, introduction of abnormality sign determination system (ASDS) will be necessary for picking up potential abnormalities of target stations caused by radiation damages, time-related deterioration and so on. It will judge abnormalities from slight state transitions of target stations based on analysis with various operational data throughout proton beams, target stations, and secondary beams during long-term operations. This report mentions present status of GCS, conceptual design of ASDS, and installation of an integral data storage server which can deal with various data for ASDS integrally.
He neutron spin filter at J-PARCOkudaira, 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：4 Percentile：76.41(Instruments & Instrumentation)Igarashi, Kai*; Onuki, Ryoji*; Sakai, Takaaki*; Kato, Shinya; Matsuba, Kenichi; Kamiyama, Kenji
Proceedings of 2020 International Conference on Nuclear Engineering (ICONE 2020) (Internet), 6 Pages, 2020/08
-rays after neutron capture by La for a T-violation searchOkudaira, Takuya; Shimizu, Hirohiko*; Kitaguchi, Masaaki*; Hirota, Katsuya*; Haddock, C. C.*; Ito, Ikuya*; Yamamoto, Tomoki*; Endo, Shunsuke*; Ishizaki, Kohei*; Sato, Takumi*; et al.
EPJ Web of Conferences, 219, p.09001_1 - 09001_6, 2019/12
Parity violating effects enhanced by up to 10
times have been observed in several neutron induced compound nuclei. There is a theoretical prediction that time reversal (T) violating effects can also be enhanced in these nuclei implying that T-violation can be searched for by making very sensitive measurements. However, the enhancement factor has not yet been measured in all nuclei. The angular distribution of the (n,) reaction was measured with La by using a germanium detector assembly at J-PARC, and the enhancement factor was obtained. From the result, the measurement time to achieve the most sensitive T-violation search was estimated as 1.4 days, and a 40% polarized La target and a 70% polarized He spin filter whose thickness is 70 atm
cm are needed. Therefore high quality He spin filter is developed in JAEA. The measurement result of the (n,) reaction at J-PARC and the development status of the He spin filter will be presented.
Okudaira, Takuya; Oku, Takayuki; Sakai, Kenji; Ino, Takashi*; Hayashida, Hirotoshi*; Hiroi, Kosuke; Shinohara, Takenao; Kakurai, Kazuhisa*; Aizawa, Kazuya; Shimizu, Hirohiko*; et al.
Proceedings of Science (Internet), 356, 5 Pages, 2019/12
The technology development section carries out the development of the neutron polarization device: 
He Spin Filter. It is often used for the fundamental physics region. In order to explain the matter-dominated universe, a time reversal violation is necessary and searches for new physics are conducted in the world. The T-violation search using a polarized neutron beam is planned at J-PARC. A large He spin filter is needed to polarize high energy neutrons for the experiment and is developed in JAEA. Recently, we developed the accurate measurement system to evaluate the polarization of He and a vacuum system to make the He spin filter, and large He spin filters for epi-thermal neutron was made using the system. The current status of the development of the He spin filter will be talked.
Sakai, Kenji; Obayashi, Hironari; Saito, Shigeru; Sasa, Toshinobu; Sugawara, Takanori; Watanabe, Akihiko*
JAEA-Technology 2019-009, 18 Pages, 2019/07
JAEA-Technology-2019-009.pdf:2.34MB
Construction of Transmutation Experimental Facility (TEF) is under planning in the Japan Proton Accelerator Research Complex (J-PARC) program to promote R&D on the transmutation technology with using accelerator driven systems (ADS). ADS Target Test Facility (TEF-T) in TEF will develop spallation target technology and study on target materials with irradiating high intensity proton beams on a lead-bismuth eutectic (LBE) target. For safe and efficient beam operation, a general control system (GCS) will be constructed in TEF-T. GCS comprises several subsystems, such as a network system (LAN), an integral control system (ICS), an interlock system (ILS), and a timing distribution system (TDS) according to their roles. Especially, the ICS plays the important role that executes integral operations in the entire facility, acquires, stores and distributes operation data. We planned to develop a prototype of the ICS, to evaluate its concrete performances such as data transmission speeds, data storage capability, control functions, long-term stability of the system, and to utilize them for design of the actual ICS. This report mentions to product the prototype of ICS and to apply it to remote operations of instruments for developing LBE target technology.
Te-NMR study on a single crystal of heavy fermion superconductor UTe
Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Hattori, Taisuke; Higa, Nonoka; Nakamine, Genki*; Kitagawa, Shunsaku*; Ishida, Kenji*; Nakamura, Ai*; Shimizu, Yusei*; et al.
Journal of the Physical Society of Japan, 88(7), p.073701_1 - 073701_4, 2019/07
Times Cited Count：29 Percentile：95.25(Physics, Multidisciplinary)We report Te-NMR studies on a newly discovered heavy fermion superconductor UTe. Using a single crystal, we have measured the Te-NMR Knight shift 
and spin-lattice relaxation rate 
for fields along the three orthorhombic crystal axes. The data confirm a moderate Ising anisotropy for both the static () and dynamical susceptibilities () in the paramagnetic state above about 20 K. Around 20 K, however, we have observed a sudden loss of NMR spin-echo signal due to sudden enhancement of the NMR spin-spin relaxation rate 
, when the field is applied along the easy axis of magnetization (=
axis). This behavior suggests the development of longitudinal magnetic fluctuations along the axis at very low frequencies below 20 K.
Sakai, Kenji; Oi, Motoki; Takada, Hiroshi; Kai, Tetsuya; Nakatani, Takeshi; Kobayashi, Yasuo*; Watanabe, Akihiko*
JAEA-Technology 2018-011, 57 Pages, 2019/01
JAEA-Technology-2018-011.pdf:4.98MB
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.
rays from neutron-induced compound states of LaOkudaira, Takuya*; Takada, Shusuke*; Hirota, Katsuya*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; Nagamoto, Kosuke*; Nakao, Taro*; Okada, Anju*; Sakai, Kenji; et al.
Physical Review C, 97(3), p.034622_1 - 034622_15, 2018/03
Times Cited Count：6 Percentile：62.89(Physics, Nuclear)-rays at the ANNRI in the MLF of the J-PARCTakada, Shusuke*; Okudaira, Takuya*; Goto, Fumiya*; Hirota, Katsuya*; Kimura, Atsushi; Kitaguchi, Masaaki*; Koga, Jun*; Nakao, Taro*; Sakai, Kenji; Shimizu, Hirohiko*; et al.
Journal of Instrumentation (Internet), 13(2), p.P02018_1 - P02018_21, 2018/02
Times Cited Count：3 Percentile：26.36(Instruments & Instrumentation)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.
Oku, Takayuki; Nakamura, Mitsutaka; Sakai, Kenji; Teshigawara, Makoto; Hideki, Tatsumoto*; Yonemura, Masao*; Suzuki, Junichi*; Arai, Masatoshi*
JAEA-Conf 2015-002, 660 Pages, 2016/02
JAEA-Conf-2015-002.pdf:168.34MB
The twenty first meeting of the International Collaboration on Advanced Neutron Source (ICANS-XXI) was held at Ibaraki Prefectural Culture Center in Mito from 29 September to 3 October 2014. It was hosted by Japan Atomic Energy Agency (JAEA), High Energy Accelerator Research Organization (KEK) and Comprehensive Research Organization for Science and Society (CROSS). In the meeting, new science and technology in the new era with the high power neuron sources were discussed in mostly "workshop style" sessions. In each session, various kinds of issues related to not only the hardware, but also the software and even radiation safety were discussed with the keyword of "INTERFACE". More than 200 Papers were presented in the meeting and 72 contributed papers are compiled in the proceedings.
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
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.
He Neutron Spin Filter (NSF) in the MLF at J-PARCSakai, 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.
