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Journal Articles

In-situ structural integrity evaluation for high-power pulsed spallation neutron source by using a laser Doppler method

Wan, T.; Naoe, Takashi; Wakui, Takashi; Haga, Katsuhiro; Kogawa, Hiroyuki; Futakawa, Masatoshi

JAEA-Conf 2015-002, p.76 - 87, 2016/02

High power accelerator driven pulsed spallation neutron sources are being developed in the world. Mercury is used as a target material to produce neutrons via the spallation reaction induced by injected protons. At the moment of the proton injection, the mercury vessel with a double wall structure is impulsively excited by the interaction between mercury and solid wall. The vibrational signals were measured in noncontact and remotely by using a Laser Doppler Vibrometer (LDV) system to evaluate the structure integrity. The extreme damages were assumed as the first step, i.e., the inner structure was partly broken by erosion. The dependency of vibrational behaviors on the damage was systematically investigated through numerical simulations and experiments. A LDV was installed to monitor the dependency of an electro-Magnetic Impact Testing Machine (MIMTM) vibration on the damage size. Through the numerical simulation, it was found that the target vessel vibration depends on the damage size. A technique referred to a Wavelet Differential Analysis (WDA) has been developed to enhance the effect of damages on the impulsive vibration behavior. However, the vibration signals obtained from MIMTM contain considerable noise. In order to reduce the noise effect on the impulsive vibration behavior, the statistical methods referred to an Analysis of Variance (ANOVA) and an Analysis of Covariance (ANCOVA) was applied. Numerical simulation results that obtained from controlling the damage size, were firstly added to random noise with various levels manually, and then were analyzed by the statistic methods. Then, the field data that measured from the real mercury target was analyzed. The results represent that the combination of WDA and ANOVA/ANCOVA could effectively indicate the damage dependency.

Journal Articles

MAGIC chopper; Basic concept and experimental evaluation

Nakamura, Mitsutaka; Ikeuchi, Kazuhiko*; Kajimoto, Ryoichi; Kambara, Wataru; Krist, T.*; Shinohara, Takenao; Arai, Masatoshi; Iida, Kazuki*; Kamazawa, Kazuya*; Inamura, Yasuhiro; et al.

JAEA-Conf 2015-002, p.339 - 348, 2016/02

We have developed a new Fermi chopper referred to as Magic chopper to realize the full optimization of the experimental condition for Multi-Ei method in a chopper spectrometer. In this study, the theoretical aspects of MAGIC chopper concept will be initially presented, and the performances of MAGIC chopper will be evaluated by both Monte Carlo simulation and neutron transmission experiment.

Journal Articles

Recent progress in the chopper spectrometer 4SEASONS at J-PARC

Kajimoto, Ryoichi; Nakamura, Mitsutaka; Inamura, Yasuhiro; Kamazawa, Kazuya*; Ikeuchi, Kazuhiko*; Iida, Kazuki*; Ishikado, Motoyuki*; Nakajima, Kenji; Kawamura, Seiko; Nakatani, Takeshi; et al.

JAEA-Conf 2015-002, p.319 - 329, 2016/02

Journal Articles

Progress of the general control system for the Materials and Life Science Experimental Facility in J-PARC

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.

Oral presentation

X/S-band electron linac based neutron sources for advanced nuclear science & technology & education

Uesaka, Mitsuru*; Tagi, Kazuhiro*; Matsuyama, Daiki*; Fujiwara, Takeshi*; Dobashi, Katsuhiro*; Yamamoto, Masashi*; Harada, Hideo

no journal, , 

Oral presentation

Neutron diffraction imaging at NOVA (J-PARC), HRPD, RESA, and TNRF (JRR-3)

Shamoto, Shinichi; Imaki, Tadashi*; Oshita, Hidetoshi*; Nakatani, Takeshi; Kodama, Katsuaki; Kaneko, Naokatsu*; Suzuki, Hiroshi; Iikura, Hiroshi; Moriai, Atsushi; Matsubayashi, Masahito; et al.

no journal, , 

Neutron diffraction imaging for a SUS430 plate embedded in a copper block sample has been tested at the high-intensity total diffractometer NOVA in J-PARC, the High-Resolution Powder Diffractometer HRPD and the diffractometer for Residual Stress Analysis RESA in JRR-3. The results are also compared with that measured at the Thermal Neutron Radiography Facility TNRF in JRR-3.

Oral presentation

Present status of sample environment at J-PARC MLF

Aso, Tomokazu; Yamauchi, Yasuhiro; Sakaguchi, Yoshifumi*; Munakata, Koji*; Ishikado, Motoyuki*; Kawamura, Seiko; Yokoo, Tetsuya*; Watanabe, Masao; Takata, Shinichi; Hattori, Takanori; et al.

no journal, , 

In FY2013, the SE team was officially organized in Technology Development Section in MLF with succeeding the previous ad hoc SE team. We are working on operation of so-called beam-line (BL)-common SE equipment and development of the SE devices as well as the previous SE team. We have already prepared a vertical-field superconducting magnet, a dilution refrigerator insert, a furnace with Nb heater and 2K cryostat as the BL-common SE equipment. In this fiscal year, a bottom-loading type $$^{3}$$He cryostat will be introduced. Moreover, we have just started developing high pressure system by collaborating with High Pressure Group in MLF, to comply with users' requests. We have also discussed the general purpose of apparatus for pulse magnet and for hydrogen environment. We plan to prepare more working area for the SE equipment, whose number gradually increases, and sample preparation and characterization rooms for users in the new building, which is under construction.

Oral presentation

J-PARC; The Path to 1 MW at J-PARC, including 400 MeV linac improvement, RCS improvements, and front-end upgrades

Yamamoto, Kazami

no journal, , 

An accelerator system of Japan Proton Accelerator Research Complex (J-PARC) operated since May 2008 for neutron experiments. The accelerator system consists Linac, Rapid Cycling synchrotron (RCS) and Main Ring. The original design of RCS injection energy is 400 MeV, but first operation was started by 181 MeV for budget reason. New acceleration cavities were installed in J-PARC linac summer shutdown of 2013, and user operation to Material and Life science Facility (MLF) with 400 MeV injection energy was started from February 2014. Owing to the beam commissioning with 400 MeV injection energy, the amount of the beam loss was enough small and we established 300 kW continuous operation. In this paper, we report the present status and future plan of J-PARC linac and RCS.

Oral presentation

Neutron diffractometer encompassing protein crystals with large unit cell volume at J-PARC

Kurihara, Kazuo; Tomoyori, Katsuaki; Tamada, Taro; Kuroki, Ryota

no journal, , 

Many proteins, especially membrane proteins and protein complexes, have larger molecular weight and then unit cells of their crystals have larger volume. Therefore, our group had designed the diffractometer which can cover such crystals with large unit cell volume (target lattice length: 250${AA}$) at J-PARC. In order to separate spots closer to each other in spatial as well as time dimension in diffraction images, our proposed diffractometer adopts longer camera distance ($$L$$2 = 800mm) and selects decoupled hydrogen moderator as neutron source which has shorter pulse width. Under the conditions that $$L$$1 is 33.5m, beam divergence 0.4$$^{circ}$$ and crystal edge size 2mm, this diffractometer is estimated to afford the resolution ($$Delta$$$$d/d$$) of 1% at the middle and high 2$$theta$$$$_{S}$$ angles and be able to resolve spots diffracted from crystals with a lattice length of 220${AA}$ in each axis at $$d$$-space of 2.0${AA}$. In order to increase measurement efficiency, novel large-area detector (larger than 300mm $$times$$ 300mm) with a spatial resolution of better than 2.5mm is under development. More than 40 detectors plan to be installed, providing the total solid angle coverage of larger than 33%.

Oral presentation

Localization of the beam loss caused by the foil scattering for high-intensity routine operation in the J-PARC 3-GeV Rapid Cycling Synchrotron

Kato, Shinichi; Yamamoto, Kazami; Harada, Hiroyuki; Hotchi, Hideaki; Kinsho, Michikazu

no journal, , 

The J-PARC 3-GeV rapid cycling synchrotron (RCS) accelerates proton beams from 400 MeV to 3 GeV and the designed output beam power is 1 MW. To achieve a high-intensity output beam power, the RCS adapts H$$^{-}$$ charge-exchange multi-turn injection. The H$$^{-}$$ beam from the Linac is delivered to the RCS injection point, where it is injected through a carbon stripper foil in order to strip two electrons and to convert into proton. This injection is divided into 308 turns. Therefore, the both injection and circulating beams hit the foil repeatedly and scattering occur during the injection. Especially, large-scattered particles cause uncontrolled beam losses at downstream area. Thus, a new collimation system was developed and installed downstream of the foil to localize these losses in 2011. In the beam commissioning at 181 MeV and 400 MeV injection energy, unique tuning method of the collimator has been established and consequently these uncontrolled beam losses were localized successfully.

Oral presentation

Present status of BL19 TAKUMI at J-PARC

Harjo, S.; Aizawa, Kazuya; Kawasaki, Takuro; Gong, W.; Iwahashi, Takaaki; Ito, Takayoshi*; Abe, Jun*; Nakatani, Takeshi

no journal, , 

Oral presentation

Magnetic shield design of in-situ SEOP polarized $$^{3}$$He neutron spin filter for high magnetic field sample environment accessories at J-PARC

Kira, Hiroshi*; Hayashida, Hirotoshi*; Oku, Takayuki; Sakai, Kenji; Hiroi, Kosuke; Ino, Takashi*; Oyama, Kenji*; Okawara, Manabu*; Kakurai, Kazuhisa; Suzuki, Junichi*; et al.

no journal, , 

Oral presentation

Neutron diffraction study of piezoelectric material under cyclic electric field using event recording technique

Kawasaki, Takuro; Ito, Takayoshi*; Inamura, Yasuhiro; Nakatani, Takeshi; Harjo, S.; Gong, W.; Iwahashi, Takaaki; Aizawa, Kazuya

no journal, , 

Oral presentation

Recent status of a cold neutron disk chopper spectrometer AMATERAS

Nakajima, Kenji; Kawamura, Seiko; Kikuchi, Tatsuya; Kawakita, Yukinobu; Inamura, Yasuhiro; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Soyama, Kazuhiko; Harada, Masahide; Oikawa, Kenichi; et al.

no journal, , 

Oral presentation

Development of compact laser optics for an in-situ spin-exchange optical pumping $$^3$$He neutron spin filter

Oku, Takayuki; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Shinohara, Takenao; Sakaguchi, Yoshifumi*; Ino, Takashi*; Oyama, Kenji*; Chang, L.-J.*; et al.

no journal, , 

The $$^3$$He NSF is effective even for neutrons with energy higher than several-tens-meV, so that it will be useful for the study of high-energy magnetic excitation. Since the $$^3$$He NSF can also cover a large solid angle and polarize neutrons without deflecting them from their original course, it is suitable for the analyzer for SANS instruments and reflectometers. In order to apply the $$^3$$He NSF to experiments at a pulsed neutron experimental facility such as the J-PARC, it is important to make the system stable and easy to setup and operate, because the system is located inside a radiation shield for high energy $$gamma$$ ray and neutrons. In this study, we have developed compact laser optics with a volume holographic grating (VHG) element for a spin-exchange optical pumping (SEOP) system, and composed an in-situ SEOP $$^3$$He NSF. The design and performance of the in-situ SEOP $$^3$$He NSF will be then presented, and its possible application will be discussed.

Oral presentation

Thermal hydraulic design of double-walled mercury target vessel

Haga, Katsuhiro; Naoe, Takashi; Wakui, Takashi; Kogawa, Hiroyuki; Kinoshita, Hidetaka; Futakawa, Masatoshi

no journal, , 

For the mercury target of a pulsed spallation neutron source of J-PARC, cavitation damage of the target vessel wall which is caused by the pressure wave in mercury induced by high power pulsed proton beam of 1 MW is the crucial issue. So far, the analytical and experimental studies and the operational experiences of SNS suggest that the rapid mercury flow can mitigate the cavitation damages. In order to include this effect into the target design of J-PARC, we adopted doubled-walled structure to the beam window of the target vessel. The mercury flow channel with a narrow gap of 2 mm was made by adding an inner wall to just inside of the beam window. In order to investigate the mercury flow distribution and flow field, numerical simulations were carried out using the conventional code, ANSYS FLUENT. While the mercury velocity outside of the narrow channel was 1.2 m/s, the mercury velocity in the narrow channel increased to almost 4 m/s, which was promising to suppress the cavitation damages. The effect of the inner wall failure of the narrow channel on the mercury flow was also evaluated. The round hole was created on the inner wall at the center of the beam window. The simulation results and the water experimental results showed that the mercury flow velocity in the narrow channel was almost the same with the case without a hole if the hole diameter is around 10 mm.

Oral presentation

Experience on integrated interface at J-PARC/MLF

Takada, Hiroshi

no journal, , 

Oral presentation

Current status of the small and wide angle neutron scattering instrument TAIKAN at J-PARC

Takata, Shinichi; Suzuki, Junichi*; Oishi, Kazuki*; Iwase, Hiroki*; Shinohara, Takenao; Oku, Takayuki; Nakatani, Takeshi; Inamura, Yasuhiro; Ito, Takayoshi*; Tominaga, Taiki*; et al.

no journal, , 

The small and wide angle neutron scattering instrument, $$TAIKAN$$, was installed at the $$BL$$15 in the Materials and Life Science Experimental Facility, $$MLF$$, of $$J-PARC$$. $$TAIKAN$$ is designed for efficient measurement in wide-q range by using of the wide wavelength and the four detector banks which cover small-, middle-, high-, and backward-angle. At the present stage, 1,216 $$PSD$$s are mounted on $$TAIKAN$$, where the number is about 50% of the installable total $$PSD$$s number. On beam commissioning started in January 2012, and user program began in March 2012. The software of data reduction has newly developed and some sample environment devices such as a sample changer, tension tester, and refrigerator have been improved. In this presentation, we present the current status of $$TAIKAN$$ about the new software, sample environment devices, and the results on some samples to show the instrument performance of $$TAIKAN$$.

Oral presentation

Development of various shielding devices to suppress background in J-PARC

Kambara, Wataru; Aoyama, Kazuhiro; Yamauchi, Yasuhiro; Iwahashi, Takaaki; Ono, Shino; Kajimoto, Ryoichi; Nakamura, Mitsutaka; Shibata, Kaoru; Nakajima, Kenji; Kawamura, Seiko; et al.

no journal, , 

Oral presentation

The First energy-resolved neutron imaging system in the world; RADEN at J-PARC MLF

Shinohara, Takenao; Kai, Tetsuya; Oikawa, Kenichi; Segawa, Mariko; Harada, Masahide; Nakatani, Takeshi; Oi, Motoki; Sato, Hirotaka*; Kamiyama, Takashi*; Yokota, Hideo*; et al.

no journal, , 

no abstracts in English

27 (Records 1-20 displayed on this page)