JAEA-Evaluation 2019-003, 52 Pages, 2019/06
Evaluation Committee of Research Activities for J-PARC for interim assessment of Japan Proton Accelerator Research Complex evaluated the management and research activities of J-PARC center on the explanatory documents and oral presentations during the period from April 2015 to December 2018. This report summarizes the results of the assessment by the Committee with the Committee report attached.
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.
Hamon, 28(4), p.208 - 211, 2018/11
Adequate shielding of neutrons and associated -rays is of importance from viewpoints of the radiation safety of researchers and good experimental data taking by reducing the background. This article introduces basics of neutron shielding, physics and suitable materials for neutron and -ray shielding, and an example of conceptual shielding design for the 1-MW spallation neutron source of J-PARC MLF.
Aso, Tomokazu; Teshigawara, Makoto; Hasegawa, Shoichi; Muto, Hideki; Aoyagi, Katsuhiro; Nomura, Kazutaka; Takada, Hiroshi
Journal of Physics; Conference Series, 1021(1), p.012085_1 - 012085_4, 2018/06
Kai, Tetsuya; Shinohara, Takenao; Hiroi, Kosuke; Su, Y.; Oikawa, Kenichi
Hihakai Kensa, 67(5), p.209 - 216, 2018/05
no abstracts in English
Yano, Naomine*; Yamada, Taro*; Hosoya, Takaaki*; Ohara, Takashi; Tanaka, Ichiro*; Kusaka, Katsuhiro*
Scientific Reports (Internet), 6, p.36628_1 - 36628_9, 2016/12
Hiroi, Kosuke; Shinohara, Takenao; Hayashida, Hirotoshi*; Su, Y.; Kai, Tetsuya; Oikawa, Kenichi
JAEA-Technology 2016-021, 14 Pages, 2016/10
Energy resolved neutron imaging techniques have been developed at BL22 "RADEN" installed in the Materials and Life Science Experimental Facility (MLF) of J-PARC. A polarized neutron imaging technique attracts much attention as a magnetic imaging method that enables to obtain a quantitative magnetic field distribution in an industrial product under driving state. At RADEN, a polarization analysis apparatus for polarized neutron imaging experiments has been prepared, but its performance was not fully achieved due to imperfectness of the field connection between devices. To improve the performance of polarization analysis system at RADEN, we performed magnetic field simulation of this system, and optimized the magnetic field environment by evaluating the magnetic field connection. After the optimization, we rearranged devices of the system, and confirmed that uniform polarization distribution could be obtained within 44 cm field of view.
Kasugai, Yoshimi; Harada, Masahide; Kai, Tetsuya; Oi, Motoki; Meigo, Shinichiro; Maekawa, Fujio
JAEA-Data/Code 2015-033, 28 Pages, 2016/03
The high-energy neutron fluxes and spectra around the mercury spallation neutron source at MLF of J-PARC were measured by the multi-foil activation method. The threshold energies of neutron reactions utilized in this experiment covered from 0.1 to 50 MeV. The foil irradiation was carried out on the first beam-run of MLF from May 30th to 31th, 2008. After the irradiation, the induced radioactivity of each foil was measured using an HPGe detector, and the neutron-induced reaction-rate distribution around the mercury target was determined. Using these data, the high-energy neutron fluxes and spectra were deduced with unfolding method in which the neutron spectra calculated with PHITS code were used as the initial-guess spectra. By comparison between the initial and the unfolded spectra, it was shown that most of the calculation results, which had been the basis of the neutronics design of the MLF target assembly, were consistent with the experimental data within 30%.
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.
Ohara, Takashi; Kiyanagi, Ryoji; Oikawa, Kenichi; Kaneko, Koji; Kawasaki, Takuro; Tamura, Itaru; Nakao, Akiko*; Hanashima, Takayasu*; Munakata, Koji*; Moyoshi, Taketo*; et al.
Journal of Applied Crystallography, 49(1), p.120 - 127, 2016/02
Aso, Tomokazu; Yamauchi, Yasuhiro; Kawamura, Seiko
Hamon, 25(4), p.283 - 287, 2015/11
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.
Akutsu, Kazuhiro*; Ohara, Takashi
Bunseki, 2014(11), p.617 - 621, 2014/11
no abstracts in English
Iizuka, Riko*; Komatsu, Kazuki*; Kagi, Hiroyuki*; Nagai, Takaya*; Sano, Asami; Hattori, Takanori; Goto, Hirotada*; Yagi, Takehiko*
Journal of Solid State Chemistry, 218, p.95 - 102, 2014/10
In situ neutron diffraction measurements combined with the pulsed neutron source at the Japan Proton Accelerator Research Complex (J-PARC) were conducted on high-pressure polymorphs of deuterated portlandite (Ca(OD)) using a Paris-Edinburgh cell and a multi-anvil press. The atomic positions including hydrogen for the unquenchable high-pressure phase at room temperature (phase II') were first clarified. The bent hydrogen bonds under high pressure were consistent with results from Raman spectroscopy. The structure of the high-pressure and high-temperature phase (Phase II) was concordant with that observed previously by another group for a recovered sample. The observations elucidate the phase transition mechanism among the polymorphs, which involves the sliding of CaO polyhedral layers, position modulations of Ca atoms, and recombination of Ca-O bonds accompanied by the reorientation of hydrogen to form more stable hydrogen bonds.
Oikawa, Kenichi; Maekawa, Fujio; Tamura, Masaya; Harada, Masahide; Kato, Takashi; Ikeda, Yujiro; Niita, Koji*
LA-UR-06-3904, Vol.2, p.139 - 145, 2006/06
A preliminary investigation on a satellite building for a long-beamline instrument of MLF is now in progress. In order to estimate the total cost of the building, we started the shielding analysis of the beamline using MCNPX and PHITS, where the latest beamline design and the neutron spectrum have been adopted.
Oikawa, Kenichi; Kai, Tetsuya; Shinohara, Takenao; Harada, Masahide; Oi, Motoki; Sakai, Kenji; Maekawa, Fujio; Kiyanagi, Yoshiaki*
no journal, ,
Neutron imaging using a time-of-flight (TOF) method at spallation neutron source has very unique capability. Conventional neutron radiography, including computed tomography, can be carried out by use of camera type detector. In contrast, two dimensional counter with a time analyzer provides 3D data; x, y, and TOF which corresponds to the wavelength (energy) of neutrons. Since 2008, test experiments for TOF imaging has been started at NOBORU at J-PARC. TOF imaging applying resonance peak, Bragg edge, and polarized neutron have been carried out extensively. Our experiences of neutron imaging at NOBORU were fully applied to the novel imaging instrument at BL-22 of MLF now under construction.
no journal, ,
no abstracts in English
no journal, ,
no abstracts in English
Inamura, Yasuhiro; Ito, Takayoshi*; Suzuki, Jiro*
no journal, ,
The on-line monitoring system, which executes data reduction and visualization in the middle of a measurement, is strongly required by users at MLF, J-PARC. To realize useful on-line monitoring, we have developed successfully the system to read and analyze only event data increased newly by our data acquisition system by means of repeated observations of data files. This system is achieved by two developments. One is a new component of DAQ-Middleware to make position indexes in data files at a same time as neutron event recoding in order to enable fast access to a part of event data files. Another is a new function in Manyo Library to make histogram by reading repeatedly incremental events using the index information of event data files. As results, a mount of events analyzed at a time is optimized and its process time including the visualization becomes short, which works like the on-line monitoring.
no journal, ,
Although we had a difficulty of disaster and accident, we have steadily operated the neutron source. Now the accelerator power is about 300 kW, and we will ramp up to 500 kW or more in the late fall this year. Now a He-gas injection into the Hg flaw of the target is implemented. We have found the injection of the Helium micro bubbles can have a drastic effect on the target pitting mitigation. We have also installed an octupole magnet in the proton beam transport line in order to reduce peak heat deposition density in the target by flattening the peak top of the proton beam profile. All of instruments have been well operated without any serious problem. However, we have found a weak point on shielding at 1 MW. During the last operation at 300 kW, we have confirmed the performance of instruments with a new concept. New data acquisition system with the event-recording method has showed effectiveness and flexibility in experiments and versatility in data analysis.