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Journal Articles

Development of a three-dimensional computed tomography system using high-speed camera at a pulsed neutron source

Segawa, Mariko; Oi, Motoki; Kai, Tetsuya; Shinohara, Takenao; Sato, Hirotaka*; Kureta, Masatoshi

JPS Conference Proceedings (Internet), 8, p.036006_1 - 036006_6, 2015/09

Journal Articles

Measurement of transient photo-induced changes in thin films at J-PARC; Time-resolved neutron reflectivity measurements of silver photo-diffusion into Ge-chalcogenide films

Sakaguchi, Yoshifumi*; Asaoka, Hidehito; Uozumi, Yuki; Kawakita, Yukinobu; Ito, Takayoshi*; Kubota, Masato; Yamazaki, Dai; Soyama, Kazuhiko; Ailavajhala, M.*; Wolf, K.*; et al.

JPS Conference Proceedings (Internet), 8, p.031023_1 - 031023_6, 2015/09

We report recent results of time-resolved neutron reflectivity measurements for silver photo-diffusion into Ge$$_{x}$$S$$_{1-x}$$ (x=0.20, 0.33, 0.40) films performed on BL17 (SHARAKU). It is well known that silver diffuses into Ge-chalcogenide layer by visible light exposure with a distinct diffusion front, where the silver concentration abruptly drops off. Using an event recording system at the Materials and Life Science Experimental Facility, neutron reflectivity profiles were collected with a time-resolution of 30 seconds in the shortest case. It was found from the measurements that a relatively stable Ag-rich phase in the reaction layer is firstly formed, and then, slower diffusion occurs at the interface between Ag-rich and Ag-poor layers. Fourier transform analysis showed that the position of the interface is essentially fixed. This result is in contrast to the previously reported model of silver diffusion that postulates a mechanism involving progression of the diffusion front. The results of the measurements on Ag/Ge-Se films performed on the INTER instrument at ISIS are also reported.

Journal Articles

Custom-made shutter block for imaging instrument "RADEN" at J-PARC

Oikawa, Kenichi; Harada, Masahide; Shinohara, Takenao; Kai, Tetsuya; Oi, Motoki; Kiyanagi, Yoshiaki*

JPS Conference Proceedings (Internet), 8, p.036002_1 - 036002_5, 2015/09

RADEN, named after the Japanese decorative craft arts, is an energy-resolved neutron imaging instrument proposed to the Materials and Life Science Experimental Facility (MLF) at J-PARC. This instrument provides various imaging fields for not only conventional radiography/tomography, but also Bragg-edge, resonance absorption and polarized neutron with good energy resolution by means of Time-of-Flight method. Construction of the instrument at BL22 started in January 2013, and on-beam commissioning will be start in November 2014. To maximize flexibility of neutron brightness, beam divergence and field of view at the sample position, an original shutter block that has a single shutter insert was replaced by a new one with three inserts.

Journal Articles

Microstructure and residual strain distribution in cast duplex stainless steel studied by neutron imaging

Su, Y.; Oikawa, Kenichi; Kawasaki, Takuro; Kai, Tetsuya; Shiota, Yoshinori*; Sato, Hirotaka*; Shinohara, Takenao; Tomota, Yo*; Harada, Masahide; Kiyanagi, Ryoji; et al.

JPS Conference Proceedings (Internet), 8, p.031015_1 - 031015_5, 2015/09

In this study, neutron imaging experiment was performed using NOBORU, BL10 of MLF at J-PARC. Four kinds of cast duplex stainless steel with ferrite and austenite microstructure were studied here, which were produced by different casting method at different temperature. Firstly, two-dimensional scintillation detector using wavelength-shifting fibers with pixel size of 0.52 mm $$times$$ 0.52 mm and illuminated area 55 mm $$times$$ 55 mm was used for data collection. Then, measurement by Micro Pixel Chamber based neutron imaging detector having higher spatial resolution about 0.2 mm was conducted. Data analysis code RITS (Rietveld Imaging of Transmission Spectra) will be used for microstructure including crystalline phase, lattice strain, crystallite size, texture evaluation.

Journal Articles

Online monitoring of negative muon beam profiles at J-PARC MUSE using a gated image intensifier

Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko*; Kubo, Kenya*; Kawamura, Naritoshi*; Shimomura, Koichiro*

JPS Conference Proceedings (Internet), 8, p.036014_1 - 036014_5, 2015/09

Journal Articles

Background caused by continuously emitted high-energy neutrons at the chopper spectrometer 4SEASONS

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Nakajima, Kenji; Harada, Masahide; Arai, Masatoshi

JPS Conference Proceedings (Internet), 8, p.036001_1 - 036001_6, 2015/09

Journal Articles

Inner observation of canning Cadmium by energy-selective neutron imaging at NOBORU

Harada, Masahide; Parker, J. D.*; Oikawa, Kenichi; Kai, Tetsuya; Shinohara, Takenao

JPS Conference Proceedings (Internet), 8, p.035002_1 - 035002_5, 2015/09

We found that Cadmium (Cd) was not only a suitable thermal neutron absorber as a poison material in a pulsed spallation neutron source, but also had a long life time with a small sacrifice in neutron intensities at an intense source. Therefore, we decided to use Cd as the poison material in the first moderator in JSNS/J-PARC. In the development stage of JSNS, canning of a Cd plate by an Al-alloy with the Cold Isostatic Pressing method failed and the Al-alloy cover of the Cd plate was broken. In order to correct the manufacturing process, we have to observe the inside of the sample to find the reason for failure. To investigation the inside of the canning Cd plate non-destructively, we applied the energy selective neutron imaging method. We measured the transmission of the canning Cd plate used by the micro-pixel chamber ($$mu$$PIC) neutron detector at NOBORU (BL10) in JSNS. As a result, several vacancies could be found and the distribution of the amount of Cd could be also obtained.

Journal Articles

Dislocation characteristics of martensitic steel studied by ${it in situ}$ neutron diffraction experiment

Kawasaki, Takuro; Harjo, S.; Gong, W.; Aizawa, Kazuya; Iwahashi, Takaaki; Shi, Z.*; Li, J.*; Tomota, Yo*; Ung$'a$r, T.*

JPS Conference Proceedings (Internet), 8, p.031009_1 - 031009_5, 2015/09

To evaluate the characteristics of the microstructure of materials, such as dislocation density, dislocation character and crystalline size, is as important as elastic strain in order to understand the mechanical properties of the materials. These characteristics can be obtained by analyzing the peak profile in X-ray or neutron diffraction patterns. Although high-penetrability of neutron enables direct observation of the characteristics inside bulky materials, not much research on the microstructure which uses neutron diffraction is available. In the present study, the dislocation characteristics of a martensitic steel during tensile deformation was investigated by in-situ neutron diffraction experiment using Engineering Material Diffractometer TAKUMI at BL19 of MLF, J-PARC and CMWP method. According as the strain increases, significant increasing of the correlation between the dislocations was observed though the increasing of dislocation density is not very much.

Journal Articles

Application of Trigger counter board for synchronized data

Takahashi, Hiroki; Kawase, Masato; Ouchi, Nobuo

JPS Conference Proceedings (Internet), 8, p.012020_1 - 012020_6, 2015/09

Journal Articles

Neutron scattering study of spin fluctuations in La$$_{2-x}$$Sr$$_{x}$$CuO$$_{4}$$ by four-dimensional mapping of neutron cross-sections using the 4SEASONS chopper spectrometer

Wakimoto, Shuichi; Ikeuchi, Kazuhiko*; Arai, Masatoshi; Fujita, Masaki*; Kajimoto, Ryoichi; Kawamura, Sho*; Matsuura, Masato*; Nakajima, Kenji; Yamada, Kazuyoshi*

JPS Conference Proceedings (Internet), 8, p.034013_1 - 034013_6, 2015/09

Journal Articles

Upgrade of monitoring and operation systems for the MLF-GCS base on EPICS and CSS

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.

Journal Articles

Neutron diffraction study of 1D quantum spin system Li$$_{2}$$ZrCuO$$_{4}$$ with incommensurate magnetic structure

Yasui, Yukio*; Igawa, Naoki; Kakurai, Kazuhisa

JPS Conference Proceedings (Internet), 8, p.034012_1 - 034012_6, 2015/09

Magnetic structure has been studied by using neutron diffraction for quasi one-dimensional quantum spin system Li$$_{2}$$ZrCuO$$_{4}$$ with CuO$$_{2}$$ ribbon chains. The CuO$$_{2}$$ ribbon system Li$$_{2}$$ZrCuO$$_{4}$$ exhibits the antiferromagnetic transition at T$$_{N}$$ $$sim$$ 7 K, however, the magnetic transition is not accompanied with ferroelectricity. At 3K, we observed magnetic superlattice reflections at Q = (0, k, l$$pm$$$$delta$$) and (h, 0, l$$pm$$$$delta$$) (h, k and l = even) with $$delta$$$$sim$$ 0.488 by the powder neutron diffraction. By the combined studies of neutron diffraction and magnetization data, the magnetic structure of Li$$_{2}$$ZrCuO$$_{4}$$ is proposed. On the bases of the obtained data, reasons for absence of ferroelectricity in Li$$_{2}$$ZrCuO$$_{4}$$ are discussed.

Journal Articles

Thermal strain in superconducting Nb$$_{3}$$Sn strand at cryogenic temperature

Harjo, S.; Kawasaki, Takuro; Hemmi, Tsutomu; Ito, Takayoshi*; Nakamoto, Tatsushi*; Aizawa, Kazuya

JPS Conference Proceedings (Internet), 8, p.031001_1 - 031001_5, 2015/09

Journal Articles

Operation status of the J-PARC ion source

Oguri, Hidetomo; Okoshi, Kiyonori; Ikegami, Kiyoshi*; Yamazaki, Saishun; Takagi, Akira*; Koizumi, Isao; Ueno, Akira

JPS Conference Proceedings (Internet), 8, p.011009_1 - 011009_6, 2015/09

Journal Articles

Analytical estimation of the field modulation during the injection period of the 3 GeV RCS in J-PARC

Shobuda, Yoshihiro; Irie, Yoshiro*

JPS Conference Proceedings (Internet), 8, p.012003_1 - 012003_6, 2015/09

Journal Articles

The Residual gas ionization profile monitor in the J-PARC 3-GeV Rapid Cycling Synchrotron

Harada, Hiroyuki; Kato, Shinichi*

JPS Conference Proceedings (Internet), 8, p.012011_1 - 012011_6, 2015/09

The residual gas Ionization Profile Monitor (IPM) is developed in the J-PARC 3-GeV RCS. The IPM is a non-destructive beam profile monitor to observe a circulating transverse beam profile in the ring. It is very important to observe the beam profile turn-by-turn in the ring for identification of the beam loss and emittance growth source because the beam power of accelerator is limited by the beam loss from the view point of radio activation at these accelerator devices. The detail IPM system are introduced and latest results in beam commissioning will be reported in this presentation.

Journal Articles

Design of injection and extraction at an 8-GeV booster ring and the J-PARC Main Ring for Multi-MW output beam power

Harada, Hiroyuki; Hotchi, Hideaki; Igarashi, Susumu*; Sato, Yoichi*; Koseki, Tadashi

JPS Conference Proceedings (Internet), 8, p.012012_1 - 012012_6, 2015/09

The 240-kW output beam power in the J-PARC 50-GeV Main Ring (MR) has been achieved for the 30-GeV user operation with the cycle time of 2.48 sec and the injected beam intensity with the output beam power of 380-kW equivalent from 3-GeV Rapid Cycling Synchrotron (RCS). The target of output beam power in MR is 750-kW by faster cycling and the injected beam intensity of 600-kW equivalent beam from the RCS. The MR are developing the new type power supplies of the MR main magnets and the high-impedance core of the MR RF cavities. The RCS will aim the designed output beam power of 1-MW from the beam commissioning on October 2014 after the peak current upgrade of Linac from 30 to 50-mA. For higher beam power of MR, we have explored the accelerator options. As one of options, 8-GeV Booster Ring (BR) is also designed for increasing the injection energy of the MR. The increasement of injection energy leads to the reducing a space charge force and the increasing the acceptance clearance from the physical aperture of the MR. In this paper, the realistic injection and extraction system of the BR and the new injection system of the MR for Multi-MW output beam power are also described.

Journal Articles

Introducing an 8-GeV booster synchrotron between RCS and MR at J-PARC; One possible option toward a multi-MW output beam power from MR

Hotchi, Hideaki; Harada, Hiroyuki; Yamamoto, Masanobu; Igarashi, Susumu*; Koseki, Tadashi*; Sato, Yoichi*

JPS Conference Proceedings (Internet), 8, p.012008_1 - 012008_6, 2015/09

Now the J-PARC accelerators (Linac, 3GeV RCS, 50GeV MR) are in transition from the initial beam commissioning phase to the final stage aiming for the design output beam power of 1 MW from RCS and 0.75 MW from MR; RCS is to start 1-MW beam tuning from October 2014 after completing the linac upgrade, and MR aims at 0.75 MW within the next 3 years by introducing new main magnet power supplies with the faster cycling time. In view of such current situation, we have started discussions for the future J-PARC accelerator concept toward a Multi-MW output beam power. In this paper, we discuss the feasibility for the introduction of a new 8-GeV booster synchrotron between RCS and MR as one possible option toward a Multi-MW output beam power from MR, in combination with the RCS beam power upgrade from 1 MW to 2 MW.

Journal Articles

Optics tuning for beam collimation in the J-PARC 3-50 beam transport line

Harada, Hiroyuki; Meigo, Shinichiro; Shirakata, Masashi*; Sato, Yoichi*; Tamura, Fumihiko; Tejima, Masaki*; Hashimoto, Yoshinori*; Igarashi, Susumu*; Koseki, Tadashi

JPS Conference Proceedings (Internet), 8, p.012010_1 - 012010_6, 2015/09

The J-PARC 3-50BT line is the beam transport line from 3-GeV rapid-cycling synchrotron (RCS) to 50-GeV main ring (MR). The RCS is the high-intensity proton accelerator, where designed beam power is 1 MW, and has the complex source of space charge effect, etc. Therefore, the uncontrolled emittance growth and beam halo increase nonlinearly with the increasing the beam power. Additionally, the physical aperture of MR with 81 $$pi$$ mm mrad is smaller than that of RCS with 486 $$pi$$ mm mrad. Therefore, the 3-50BT line has the collimators in order to remove the tail or halo of the extracted beam from the RCS. The designed collimator aperture is 54 $$pi$$ mm mrad. It is required to measure and optimize the optics parameters in the collimator area for taking full advantage of the beam collimation. Especially, it is very important to make the dispersion functions free in the collimator area and optimize the beta function. This paper will introduce the method of optics measurement and report the result of the measurement and optimization based on the simulation.

Journal Articles

Beam monitors for the commissioning of energy upgraded linac

Miura, Akihiko; Maruta, Tomofumi*; Liu, Y.*; Miyao, Tomoaki*; Kawane, Yusuke; Ouchi, Nobuo; Oguri, Hidetomo; Ikegami, Masanori*; Hasegawa, Kazuo

JPS Conference Proceedings (Internet), 8, p.011002_1 - 011002_6, 2015/09


In the J-PARC Linac, an energy upgrade project has started since 2009 using Annular-ring Coupled Structure cavities to achieve design beam power of 1 MW at the exit of the downstream rapid cycling synchrotron. Linac beam parameters of the upgraded Linac is drastically improved especially for the beam energy from 181 to 400 MeV in the project. To meet with the significant upgrades of the Linac, beam monitors to be used for the upgraded beam line are newly designed and fabricated as well as the beam monitor layout is designed with the consideration to the beam commissioning strategies. This paper introduces the beam monitor layout in the new beam line and the commissioning results to confirm the beam monitor functioning.

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