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Journal Articles

Characterization of liquid targets in Vacuum condition

Yamamoto, Kazami; Ogiwara, Norio*; Kuramochi, Masaya*

e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.359 - 364, 2023/07

In recent years, durable target is required according to increase of the beam power. To solve this problem, a liquid film was formed in vacuum and tested it as a target. An ethanol and a mercury were selected as liquid target materials, and we investigated whether the liquid sheet could be formed stably in a vacuum and how about the vacuum pressure. As a result, it was confirmed that the liquid films were stably formed in both case and the pressures with the films were about the vapor pressure of the materials.

Journal Articles

A Knowledge-sharing activity on the environmental radiation monitoring results affected by the Fukushima-Daiichi Nuclear Power Plant Accident at Tokai-Oarai area in Ibaraki Prefecture

Nakano, Masanao; Hosomi, Kenji; Nishimura, Shusaku; Matsubara, Natsumi; Okura, Takehisa; Kuramochi, Akihiko; Kawasaki, Masatsugu; Takeuchi, Erina; Fujii, Yutaka*; Jinno, Tsukasa*; et al.

Hoken Butsuri (Internet), 55(2), p.102 - 109, 2020/06

After the Fukushima-Daiichi Nuclear Power Station (1F) Accident in March 2011, the increase was significantly observed in a part of the result of the environmental radiation monitoring in Ibaraki prefecture. "The review meeting of the environmental effect from 1F accident" was established to discuss technically the fluctuation of monitoring data. The review meeting collected the monitoring data from the four nuclear operators, and discussed a fluctuating trend, $$^{134}$$Cs/$$^{137}$$Cs activity ratio, and so on. In this report, the results of the dose rate and $$^{137}$$Cs in fallout, surface soil, flatfish and seabed sediment are introduced. Also the problem solving in the review meeting is introduced.

Journal Articles

Feeder components and instrumentation for the JT-60SA magnet system

Yoshida, Kiyoshi; Kizu, Kaname; Murakami, Haruyuki; Kamiya, Koji; Honda, Atsushi; Onishi, Yoshihiro; Furukawa, Masato; Asakawa, Shuji; Kuramochi, Masaya; Kurihara, Kenichi

Fusion Engineering and Design, 88(9-10), p.1499 - 1504, 2013/10

 Times Cited Count:6 Percentile:44.21(Nuclear Science & Technology)

The modifying of the JT-60U magnet system to the superconducting coils (JT-60SA) is progressing as a satellite facility for ITER by both parties of Japanese government and European commission (EU) in the Broader Approach agreement. The magnet system for JT-60SA consists of 18 Toroidal Field (TF) coils, a Central Solenoid (CS) with 4 modules, and 6 Equilibrium Field (EF) coils. The manufacturing of the JT-60SA magnet system is in progress in EU and Japan. The JT-60SA superconducting magnet system generates an average heat load of 3.2 kW at 4 K to the cryoplant, from nuclear and thermal radiation, conduction and electromagnetic heating, and requires current supplies 20 kA for 4 CS modules and 6 EF coils, 25.7 kA to 18 TF coils. The helium flow to remove this heat, consisting of supercritical helium at pressures up to 0.5 MPa and temperature between 4.4-4.8 K, is distributed to the coils and structures through the valve box (VB) from the cryoline connecting to the auxiliary cold box located outside the torus hall. The feeders also contain the electrical supplies from the current lead transitions to room temperature to the coil. The feeder components consist of the in-cryostat feeders with flexible parts to allow coil operational displacements from the connection pipes out of the cryostat, including S-bend conductor to allow differential thermal contraction and the coil terminal boxes (CTBs) with HIS current leads. A measurement and control system is required to monitor and control these coils and feeders for safety and optimal operational availability. For each coil, both current and supercritical helium are supplied from external systems and are controlled from a central system as part of the regular operation with plasma pulses. Quench detection instruments for superconducting coils, feeders and HTS current leads are provided as a separate, stand alone system.

Journal Articles

$$^{13}$$C-selective infrared multiple photon dissociation of $$beta$$-propiolactone by a free electron laser

Miyomoto, Yoshiki*; Majima, Tetsuro*; Arai, Shigeyoshi*; Katsumata, Keiichi*; Akagi, Hiroshi; Maeda, Akihiko*; Hata, Hiroo*; Kuramochi, Koji*; Kato, Yoshiyasu*; Tsukiyama, Koichi*

Nuclear Instruments and Methods in Physics Research B, 269(2), p.180 - 184, 2011/01

 Times Cited Count:12 Percentile:66.95(Instruments & Instrumentation)

Journal Articles

Recent progress of the design activity for the poloidal field coil system in JT-60SA

Tsuchiya, Katsuhiko; Kizu, Kaname; Murakami, Haruyuki; Asakawa, Shuji; Kuramochi, Masaya; Yoshida, Kiyoshi; Tomarchio, V.*

IEEE Transactions on Applied Superconductivity, 20(3), p.525 - 529, 2010/06

 Times Cited Count:8 Percentile:45.77(Engineering, Electrical & Electronic)

The programme of constructing JT-60SA device is progressing under the framework of the Broader Approach (BA) agreement decided by Japan (JA) and European Union (EU). The magnet system for JT-60SA consists of 18 toroidal field (TF) coils, a central solenoid (CS) with four modules, six equilibrium field (EF) coils. It is decided in the agreement between JA and EU that the poloidal field magnet system, CS and EF coils, shall be procured by JA. The CS consists of independent winding pack modules, which is hung from the top of the TF coils through its pre-load structure. The six EF coils are attached to the TF coil cases through supports that include flexible plates allowing radial displacements. In the procurement arrangement (PA) for CS and EF coils that was recently agreed by JA and EU, basic mechanical designs of CS and EF coils are prescribed in the basis of structural analysis. The equipment for the mass-production of conductors for CS and EF coils is prepared by JAEA. And JAEA also prepare the equipment for the fabrication of EF coils in the field of JAEA Naka site because these coils have large bores. In this paper, we describe the recent mechanical design of poloidal field coils, and evaluation result for the support structure.

JAEA Reports

Structure design of the central solenoid in JT-60SA

Asakawa, Shuji; Tsuchiya, Katsuhiko; Kuramochi, Masaya; Yoshida, Kiyoshi

JAEA-Technology 2009-044, 55 Pages, 2009/09

JAEA-Technology-2009-044.pdf:4.92MB

The upgrade of JT-60U magnet system to superconducting coils (JT-60SA: JT-60 Super Advanced) has been decided by parties of Japanese government (JA) and European commission (EU). The magnet system for JT-60SA consists of a central solenoid (CS), equilibrium field (EF) coils, toroidal field (TF) coils. The central solenoid consists of the four winding pack modules. In order to counteract the thermal contraction as well as the electric magnetic repulsion and attraction together with other forces generated in each module, it is necessary to apply pre-loading to the support structure of the solenoid and to pursue a structure which is capable of sustaining such loading. In the present report, the structural design of the supporting structure of the solenoid and the jackets of the conducting coils in the modules is verified analytically, and the results indicate that the structural design satisfies the "Codes for Fusion Facilities Rules on Superconducting Magnet Structure".

Journal Articles

Magnetic field mapping and excitation test in vacuum for the kicker magnet in J-PARC RCS

Kamiya, Junichiro; Kinsho, Michikazu; Kuramochi, Masaya; Takayanagi, Tomohiro; Takeda, Osamu; Ueno, Tomoaki; Watanabe, Masao; Yamamoto, Kazami; Yamazaki, Yoshio; Yoshimoto, Masahiro

IEEE Transactions on Applied Superconductivity, 18(2), p.293 - 296, 2008/06

 Times Cited Count:3 Percentile:26.12(Engineering, Electrical & Electronic)

The kicker magnets are installed in the extraction section in the Rapid Cycling Synchrotron (RCS) of J-PARC and they extract a proton beam accelerated up to 3 GeV. We performed the mapping in the air applying one third of operational voltage after checking linear dependence of magnetic field with excitation current. A short search coil with the 3-axias stage was used to measure the magnetic field distribution. The results showed that the distribution in the medium plane of the same type of kicker magnet is in good agreement with each other. The excitation test with the operational charging voltage of 60 kV was also performed in a vacuum. At the first stage, we were bothered by the electric breakdown. It was noticed that the reduction of outgassing rate by baking is very effective to suppress the discharge. Pressure and mass spectrum measured during the excitation test showed that the excitation of the kicker magnet has conditioning effect.

Journal Articles

Improvement of the shift bump magnetic field for a closed bump orbit of the 3-GeV RCS in J-PARC

Takayanagi, Tomohiro; Kanazawa, Kenichiro; Ueno, Tomoaki; Someya, Hirohiko*; Harada, Hiroyuki*; Irie, Yoshiro; Kinsho, Michikazu; Yamazaki, Yoshishige; Yoshimoto, Masahiro; Kamiya, Junichiro; et al.

IEEE Transactions on Applied Superconductivity, 18(2), p.306 - 309, 2008/06

 Times Cited Count:10 Percentile:50.83(Engineering, Electrical & Electronic)

The four shift bump magnets (BUHS01-04) of the 3-GeV RCS in J-PARC, which are located at the long straight section, produce a fixed main bump orbit to merge the injection beam into the circulating beam. They are realized with four magnets connected in series to form the accurate closed bump orbit. However, the total integrated magnetic field of the four magnets is not zero because of the magnetic field interferences between the shift bump magnet and the adjacent quadrupole magnet (Q magnet). In order to decrease the imbalance of the integrated magnetic field, 0.3mm insulators were inserted at the median plane of the return yoke of the second and third shift bump magnets (BUHS02 and BUHS03). The integrated field has been decreased from 2358.0 Gauss-cm to -71.6 Gauss-cm, resulting in the closed orbit distortion of the beam to be decreases from 6.0 mm to less than 1.0 mm.

Journal Articles

Measurement of the paint magnets for the beam painting injection system in the J-PARC 3-GeV RCS

Takayanagi, Tomohiro; Kanazawa, Kenichiro; Ueno, Tomoaki; Someya, Hirohiko*; Harada, Hiroyuki*; Irie, Yoshiro; Kinsho, Michikazu; Yamazaki, Yoshishige; Yoshimoto, Masahiro; Kamiya, Junichiro; et al.

IEEE Transactions on Applied Superconductivity, 18(2), p.310 - 313, 2008/06

 Times Cited Count:2 Percentile:20.21(Engineering, Electrical & Electronic)

The beam painting injection system of the 3-GeV RCS in J-PARC, which realizes the uniform beam distributions in the ring, consists of four horizontal paint bump magnets and two vertical paint magnets. Each paint bump magnet power supply is required to excite the current with high accuracy that varies from 17.6 kA to zero during 0.5 msec. The IGBT chopper units, the switching frequency of which is 50 kHz each, are multiple connected to achieve the effective carrier frequency of 600 kHz. The output accuracy is then achieved to be less than 1 %. The measurements of the magnetic field with the actual current waveform were performed and the good performance was confirmed.

Journal Articles

Design and construction of septum magnets at 3-GeV RCS in J-PARC

Yoshimoto, Masahiro; Ueno, Tomoaki; Togashi, Tomohito; Takeda, Osamu; Kanazawa, Kenichiro; Watanabe, Masao; Yamazaki, Yoshio; Kamiya, Junichiro; Takayanagi, Tomohiro; Kuramochi, Masaya; et al.

IEEE Transactions on Applied Superconductivity, 18(2), p.297 - 300, 2008/06

 Times Cited Count:4 Percentile:30.92(Engineering, Electrical & Electronic)

Journal Articles

Field measurement of DC magnets at 3-GeV RCS in J-PARC

Yoshimoto, Masahiro; Ueno, Tomoaki; Togashi, Tomohito; Toyokawa, Ryoji; Takeda, Osamu; Watanabe, Masao; Yamazaki, Yoshio; Yamamoto, Kazami; Kamiya, Junichiro; Takayanagi, Tomohiro; et al.

IEEE Transactions on Applied Superconductivity, 18(2), p.301 - 305, 2008/06

 Times Cited Count:1 Percentile:12.91(Engineering, Electrical & Electronic)

Journal Articles

Commissioning results of the kicker magnet in J-PARC RCS

Kamiya, Junichiro; Kinsho, Michikazu; Kuramochi, Masaya; Takayanagi, Tomohiro; Togashi, Tomohito; Ueno, Tomoaki; Watanabe, Masao; Yoshimoto, Masahiro

Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.3590 - 3592, 2008/06

Installation of the kickers in the extraction section of the RCS in J-PARC facility was completed. And they succeeded to extract the proton beams accelerated up to 3 GeV in the first beam test. The operation parameters of the kickers agreed well with the parameters which were estimated from the magnetic field measurement and the current test of the each power supply. In this report, we summarized the results of the excitation test and the commissioning of the kicker magnet. Combining the results of the magnetic field measurements, the relation between the setup charging voltage and the integrated magnetic field was obtained for each kicker. The accelerated beam was successfully extracted at the operation parameters which were obtained from the relationship. The measurements result which was obtained by using the beam is also reported.

Journal Articles

Reduction of outgassing for suppressing electrical breakdown in the kicker magnet of J-PARC RCS

Kamiya, Junichiro; Kinsho, Michikazu; Ogiwara, Norio; Kuramochi, Masaya; Ueno, Tomoaki; Takayanagi, Tomohiro; Takeda, Osamu; Watanabe, Masao; Yamazaki, Yoshio; Yoshimoto, Masahiro

Shinku, 50(5), p.371 - 377, 2007/05

Kicker magnets in Rapid Cycling Synchrotron (RCS) of Japan Proton Accelerator Research Complex (J-PARC) are now under construction. The kicker magnets are short pulse magnets with high charging voltage of 60 kV or more which is installing in vacuum chambers. The kicker magnet mainly consists of aluminum alloy as electric plates and ferrite as magnetic cores. The outgas reduction from those components is very important to prevent not only electrical discharge but also interaction between the proton beam and residual gas in the vacuum. We thoroughly reduced the outgas from the components. Surface of the aluminum alloy was finished by pit-free electropolishing. Aluminum and ferrites were baked in vacuum before construction of the magnet. They were baked each other until water, which was the main component of outgas, was reduced. We will discuss the effects of above processes on the discharge in the vacuum.

Journal Articles

Experimental results of the shift bump magnet in the J-PARC 3-GeV RCS

Takayanagi, Tomohiro; Ueno, Tomoaki; Irie, Yoshiro; Kinsho, Michikazu; Takeda, Osamu; Yamazaki, Yoshishige; Yoshimoto, Masahiro; Kamiya, Junichiro; Watanabe, Masao; Kuramochi, Masaya

Proceedings of 10th European Particle Accelerator Conference (EPAC 2006) (CD-ROM), p.1762 - 1764, 2006/00

The shift bump magnet produces a fixed main bump orbit to merge the injection beam into the circulating beam. In order to control the injection beam for the short injection time (500 microseconds) with sufficient accuracy, the shift bump magnet needs a wide uniform magnetic field and the high speed exciting pattern of the high current. The magnetic field design and the structural analysis of the shift bump magnet have been performed using the three-dimensional electromagnetic analysis code and the mechanical analysis code, respectively. The magnetic field distributions were measured with a long search coil, thus giving a BL product over the magnet gap area. The temperature distributions at the various points of the magnet were measured by the thermocouples over 24 hours till they saturated. General trend of these measurements agrees well with calculations.

Journal Articles

Experimental and analysis of the injection bump system of the 3-GeV RCS in J-PARC

Takayanagi, Tomohiro; Ueno, Tomoaki; Kinsho, Michikazu; Takeda, Osamu; Yamazaki, Yoshio; Yoshimoto, Masahiro; Kamiya, Junichiro; Watanabe, Masao; Kuramochi, Masaya; Irie, Yoshiro

Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.74 - 76, 2006/00

The injection bump system of the 3-GeV RCS in J-PARC consists of the pulse bending magnets for the injection bump orbit, which are four horizontal bending magnets (shift bump), four horizontal painting magnets (h-paint bump) and two vertical painting magnets (v-paint bump). The magnetic field distributions of the shift bump magnet were measured with a long search coil, thus giving a BL product over the magnet gap area. Future more, the temperature distributions at the various points were measured by the thermocouples over 24 hours till they saturated. The good performance at the 181 MeV injection beam design was confirmed.

Journal Articles

Vibration measurement of the injection pulse magnet of the 3-GeV RCS in J-PARC

Ueno, Tomoaki; Takayanagi, Tomohiro; Kinsho, Michikazu; Takeda, Osamu; Yamazaki, Yoshio; Yoshimoto, Masahiro; Kamiya, Junichiro; Watanabe, Masao; Kuramochi, Masaya

Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.427 - 429, 2006/00

The injection pulse magnets of the 3GeV RCS in J-PARC are vibrated by repeating the high current exciting waveform of a high speed rising and falling. The pulse magnets have the ceramic duct in order to suppress the generation of the heat load by the eddy current and the broken by the strong vibration. Therefore, the vibration of the horizontal shift bump magnet was measured by using the CCD laser displacement meter of a high speed and a high precision.

Journal Articles

Magnetic field measurement of the extraction Kicker in J-PARC RCS

Kuramochi, Masaya; Kamiya, Junichiro; Kinsho, Michikazu; Takeda, Osamu; Yoshimoto, Masahiro; Takayanagi, Tomohiro; Watanabe, Masao; Yamazaki, Yoshio; Ueno, Tomoaki

Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.421 - 423, 2006/00

Production of the extraction kicker magnet of 3GeV RCS in J-PARC has been completed. We performed the magnetic field measurement in vacuum at the actual operation condition, which means the charging voltage of 60 kV and repetition rate of 25 Hz. We especially discuss the stability of the magnetic field and the comparison of the magnetic field between the same type of magnets.

JAEA Reports

Thermal analysis of the injection beam dump of 3 GeV rapid cycling synchrotron

Kuramochi, Masaya*; Yamamoto, Kazami; Kinsho, Michikazu

JAERI-Tech 2003-055, 148 Pages, 2003/07

JAERI-Tech-2003-055.pdf:24.48MB

The injection beam dump of the 3 GeV rapid cycling synchrotron (3 GeV-RCS) is to be installed to absorb the H$$^{-}$$ and H$$^{0}$$ beams that can not be changed into H$$^{+}$$ beam with a graphite foil. We estimate the maximum temperature and thermal stress of the injection beam dump. As a result, the temperature at the center region made of iron reached up to 370 K after several operation cycles (one cycle is three-week operation including one-week interval) under the 1kW-beam injection. Then, the temperature at the boundary between the iron region of the beam dump and the concrete wall of the tunnel was rather low temperature of about 320 K. And the maximum Mises stresses of 96 MPa and about 0.2 MPa were generated in the iron region and the concrete wall respectively. These values were much lower than the allowable temperature and stresses.

Journal Articles

The Temperature distribution calculation for the charge-exchange foils in J-PARC 3 GeV synchrotron

Kuramochi, Masaya*; Kinsho, Michikazu; Irie, Yoshiro*; Sugai, Isao*; Igarashi, Susumu*; Arakida, Yoshio*; Takeda, Yasuhiro*

Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.637 - 639, 2003/00

Three charge-exchange foils are used in J-PARC 3GeV Synchrotron(RCS). One is used for changing H$$^{-}$$ to H$$^{+}$$ by stripping electrons, and the others are used for changing H$$^{0}$$ and H$$^{-}$$ to H$$^{+}$$ which are failed to strip at the first foil. In this paper, we will describe the temperature distribution at the charge-exchange foils calculated by a simulation code 'ANSYS' where the particle distribution is based on a particle tracking code 'ACCSIM'.

Journal Articles

Progress of the ITER central solenoid model coil programme

Tsuji, Hiroshi; Okuno, Kiyoshi*; Thome, R.*; Salpietro, E.*; Egorov, S. A.*; Martovetsky, N.*; Ricci, M.*; Zanino, R.*; Zahn, G.*; Martinez, A.*; et al.

Nuclear Fusion, 41(5), p.645 - 651, 2001/05

 Times Cited Count:55 Percentile:83.06(Physics, Fluids & Plasmas)

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