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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

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

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.

Journal Articles

Bunch shape measurement of 181 MeV beam in J-PARC linac

Miura, Akihiko; Feschenko, A. V.*; Mirzojan, A. N.*; Miyao, Tomoaki*; Ouchi, Nobuo; Maruta, Tomofumi*; Liu, Y.*; Oguri, Hidetomo; Ikegami, Masanori*; Hasegawa, Kazuo

JPS Conference Proceedings (Internet), 8, p.011003_1 - 011003_6, 2015/09


In J-PARC Linac, an energy upgrade project has started since 2009 using Annular-ring Coupled Structure (ACS) cavities. We have decided to use the bunch shape monitors (BSM) as the monitors of the longitudinal beam width measurement in order to take the longitudinal matching using two bunchers located in the upstream of ACS cavities, where the RF frequency jumps from 324 to 972 MHz. Three BSMs were completely fabricated and installed in the beam line. The BSMs were commissioned with the beam and their operability was demonstrated. We found the vacuum degradation during the measurement. We once removed all BSMs to have a vacuum conditioning and postponed the longitudinal matching at the establishment of 400-MeV operation of the energy upgraded Linac. In this paper, we introduce the mechanism of the BSM, its operability, the measurement results with the 181 MeV beam and consistency check with the respect cavity amplitude. We also describe the operational vacuum conditions and the outline of the improvement of the vacuum system for the BSMs.

Journal Articles

Measurement system of the background proton in DeeMe experiment at J-PARC

Yamamoto, Kazami; Saha, P. K.; Aoki, Masaharu*; Mihara, Satoshi*; Nakatsugawa, Yohei*; Shimizu, Kosuke*; Kinsho, Michikazu

JPS Conference Proceedings (Internet), 8, p.012004_1 - 012004_5, 2015/09

The existence of a mu-e conversion process is expected by some theories beyond the standard model in particle physics, but has not been discovered yet due to its low probability. The DeeMe experiment, proposed at J-PARC Material Life Science Facility (MLF), is planned to find the mu-e conversion process on a Muon production target. In order to distinguish mu-e event signal from a background, the number of a proton that comes after hundreds of nanoseconds from the main beam should be less than one per one hour during the DeeMe experiment. Therefore we designed a new measurement system to confirm low background level. A simulation result showed that the new system could detect such delayed proton.

Journal Articles

Local lattice distortion caused by short-range charge ordering in transition metal oxides

Kodama, Katsuaki; Igawa, Naoki; Shamoto, Shinichi; Ikeda, Kazutaka*; Oshita, Hidetoshi*; Kaneko, Naokatsu*; Otomo, Toshiya*; Suzuya, Kentaro; Hoshikawa, Akinori*; Ishigaki, Toru*

JPS Conference Proceedings (Internet), 8, p.034002_1 - 034002_6, 2015/09

Journal Articles

Double hypernuclei experiment with hybrid emulsion method at J-PARC

Ekawa, Hiroyuki; J-PARC E07 Collaboration*

JPS Conference Proceedings (Internet), 8, p.021019_1 - 021019_6, 2015/09

Double hypernuclei are important probes to study the system with strangeness $$S$$ = -2. A double hypernucleus $${}^{6}_{LambdaLambda}$$He was clearly identified in the KEK E373 experiment. We are planning an upgrade experiment to search for double hypernuclei at the J-PARC K1.8 beam line. In the experiment, the KURAMA spectrometer system will detect $$Xi^-$$ production in the $$(K^-, K^+)$$ reaction on a diamond target. Tracks in SSDs and emulsion will be automatically connected by a hybrid method. This statistics is more than 10 times as high as that of the KEK E373 experiment. Discoveries of more than 10 new double hypernuclear species are expected. On the other hand, we will also observe $$X$$ rays from $$Xi^-$$ atoms with a Germanium detector array. This will be the first measurement in the world and give information on the $$Xi^-$$ potential shape at the nuclear surface region. In this talk physics motivation and current status of the J-PARC E07 experiment will be presented.

Journal Articles

TEF beam window design and evaluation of structural integrity

Obayashi, Hironari; Takei, Hayanori; Wan, T.; Kogawa, Hiroyuki; Iwamoto, Hiroki; Sasa, Toshinobu

JPS Conference Proceedings (Internet), 8, p.041002_1 - 041002_7, 2015/09

Journal Articles

Development status of the NMR system for the polarized $$^{3}$$He Neutron Spin Filter (NSF) in the MLF at J-PARC

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 $$^{3}$$He filter, which polarizes neutrons due to a large neutron absorption cross section of $$^{3}$$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 $$^{3}$$He nuclear spin polarization ${it P}$ 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 ${it P}$ 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 ${it P}$ monitor.

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