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Journal Articles

Behavior of intermolecular interactions in $$alpha$$-glycine under high pressure

Shinozaki, Ayako*; Komatsu, Kazuki*; Kagi, Hiroyuki*; Fujimoto, Chikako*; Machida, Shinichi*; Sano, Asami; Hattori, Takanori

Journal of Chemical Physics, 148(4), p.044507_1 - 044507_8, 2017/01

 Times Cited Count:6 Percentile:16.97(Chemistry, Physical)

Pressure-response on the crystal structure of deuterated $$alpha$$-glycine was investigated at room temperature, using powder and single-crystal X-ray diffraction, and powder neutron diffraction measurements under high pressure. No phase change was observed up to 8.7 GPa, although anisotropy of the lattice compressibility was found. Neutron diffraction measurements indicated the distance of the intermolecular D$$cdots$$O bond along with the $$c$$-axis increase with compression up to 6.4 GPa. The distance of another D$$cdots$$O bond along with the $$a$$-axis decreased with increasing pressure, and became the shortest intermolecular hydrogen bond above 3 GPa. In contrast, the lengths of the bifurcated N-D$$cdots$$O and C-D$$cdots$$O hydrogen bonds, which are formed between the layers of the $$alpha$$-glycine molecules along the $$b$$-axis, decreased significantly with increasing pressure. The decrease of the intermolecular distances resulted in the largest compressibility of the $$b$$-axis, compared to the other two axes. Hirshfeld analysis suggested that the reduction of the void region size, rather than shrinkage of the strong N-D$$cdots$$O hydrogen bonds, occurred with compression.

Journal Articles

Crystal structure of magnesium dichloride decahydrate determined by X-ray and neutron diffraction under high pressure

Komatsu, Kazuki*; Shinozaki, Ayako*; Machida, Shinichi*; Matsubayashi, Takuto*; Watanabe, Mao*; Kagi, Hiroyuki*; Sano, Asami; Hattori, Takanori

Acta Crystallographica Section B; Structural Science, Crystal Engineering and Materials (Internet), 71(1), p.74 - 80, 2015/02

 Times Cited Count:8 Percentile:30.21(Chemistry, Multidisciplinary)

Magnesium dichloride decahydrate (MgCl$$_{2}$$10H$$_{2}$$O) and its deuterated counterpart (MgCl$$_{2}$$10D$$_{2}$$O) are identified for the first time by in-situ powder synchrotron X-ray and spallation neutron diffraction. These substances are crystallized from a previously unidentified nanocrystalline compound, which originates from an amorphous state at low temperature. A combination of a recently developed autoindexing procedure and the charge-flipping method reveals that the crystal structure of MgCl 10H$$_{2}$$O consists of an ABCABC... sequence of Mg(H$$_{2}$$O)$$_{6}$$ octahedra. The Cl$$^{-}$$ anions and remaining water molecules unconnected to the Mg$$^{2+}$$ cations bind the octahedra, similar to other water-rich magnesium dichloride hydrates. The D positions in MgCl$$_{2}$$10D$$_{2}$$O, determined by the difference Fourier methods using the neutron powder diffraction patterns at 2.5 GPa, show the features such as bifurcated hydrogen bonds and tetrahedrally coordinated O atoms.

Journal Articles

Present status of J-PARC linac

Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.

Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10

no abstracts in English

Journal Articles

Development of RF chopper system at J-PARC Linac

Hirano, Koichiro; Ito, Takashi; Kondo, Yasuhiro; Shinozaki, Shinichi; Chishiro, Etsuji; Miura, Akihiko; Morishita, Takatoshi; Ikegami, Masanori*; Kubota, Chikashi*; Sugimura, Takashi*; et al.

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.858 - 861, 2014/06

Two RF-deflecting cavities as a chopper and a beam scraper have been used in the MEBT between a 324 MHz RFQ and a 50-MeV DTL of the J-PARC Linac. We plan to increase a peak beam current up to 50 mA by replacing an ion source and a RFQ after the summer shutdown in 2014. Beam loss occurs in the RF chopper for the 50 mA operation. Moreover, the beam scraper cannot fully stand the beam load with 50 mA, 0.5 ms, 3 MeV, and 25 Hz. We have studied the new RF chopper cavity by using HFSS code and the tandem scraper system with two scrapers.

Journal Articles

Improvement for the trip rate of klystron high-voltage power supplies in J-PARC linac

Hori, Toshihiko; Sato, Fumiaki; Shinozaki, Shinichi; Chishiro, Etsuji; Oguri, Hidetomo; Futatsukawa, Kenta*; Fukui, Yuji*

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1001 - 1003, 2014/06

no abstracts in English

Journal Articles

Present status of klystron power supply systems for J-PARC linac 2013

Kawamura, Masato*; Chishiro, Etsuji; Hori, Toshihiko; Shinozaki, Shinichi; Sato, Fumiaki; Fukui, Yuji*; Futatsukawa, Kenta*; Yamazaki, Masayoshi*; Sagawa, Ryu*; Miyajima, Noriyuki*; et al.

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.605 - 607, 2014/06

This report describes the present status of the klystron power supply systems for the J-PARC linac. The systems for the 181 MeV linac were operated from September to May. A few breakdowns were occurred, and are described in this report. The new systems for the upgrade of the linac from 181MeV to 400 MeV have been installed until now, and the 3 HVDCPSs and the 3 anode modulators of the new systems have been operated. All the systems for 400 MeV linac will be operated in this autumn.

Journal Articles

Upgrade of power supply system for RF-chopper at J-PARC Linac

Futatsukawa, Kenta*; Ikegami, Masanori*; Ito, Yuichi; Kikuzawa, Nobuhiro; Sato, Fumiaki; Shinozaki, Shinichi; Suzuki, Takahiro*; Chishiro, Etsuji; Hirano, Koichiro; Fang, Z.*; et al.

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1149 - 1153, 2014/06

no abstracts in English

Journal Articles

Upgrade of control signal distribution system at J-PARC Linac

Futatsukawa, Kenta*; Ito, Yuichi; Kikuzawa, Nobuhiro; Kobayashi, Tetsuya*; Sato, Fumiaki; Shinozaki, Shinichi; Suzuki, Takahiro*; Fang, Z.*; Fukui, Yuji*; Michizono, Shinichiro*

Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1126 - 1129, 2014/06

no abstracts in English

Journal Articles

Discharge suppression for anode modulator in J-PARC linac

Chishiro, Etsuji; Kawamura, Masato*; Hori, Toshihiko; Sato, Fumiaki; Shinozaki, Shinichi

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1224 - 1226, 2013/08

no abstracts in English

Journal Articles

High power RF test station for RFQII at J-PARC linac

Hori, Toshihiko; Chishiro, Etsuji; Shinozaki, Shinichi; Sato, Fumiaki; Morishita, Takatoshi; Kondo, Yasuhiro; Futatsukawa, Kenta*; Fukui, Yuji*; Kawamura, Masato*; Sugimura, Takashi*; et al.

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1240 - 1242, 2013/08

no abstracts in English

Journal Articles

Precise measurement of the installed cable attenuation

Futatsukawa, Kenta*; Anami, Shozo*; Kobayashi, Tetsuya*; Fang, Z.*; Fukui, Yuji*; Michizono, Shinichiro*; Sato, Fumiaki; Shinozaki, Shinichi

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.765 - 768, 2013/08

no abstracts in English

Journal Articles

Status of J-PARC linac LLRF after the Tohoku Earthquake

Futatsukawa, Kenta*; Anami, Shozo*; Kobayashi, Tetsuya*; Fang, Z.*; Fukui, Yuji*; Michizono, Shinichiro*; Kawamura, Masato*; Sato, Fumiaki; Shinozaki, Shinichi; Chishiro, Etsuji; et al.

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.769 - 773, 2013/08

no abstracts in English

Journal Articles

RF control system for the RFQ test station at J-PARC linac

Fukui, Yuji*; Kawamura, Masato*; Kobayashi, Tetsuya*; Fang, Z.*; Futatsukawa, Kenta*; Sato, Fumiaki; Shinozaki, Shinichi; Suzuki, Hiroyuki; Chishiro, Etsuji; Hori, Toshihiko; et al.

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.762 - 764, 2013/08

no abstracts in English

Journal Articles

Present status of klystron power supply systems for J-PARC linac 2012; Recovery from Earthquake Disaster, HVDCPS breakdown and energy upgrade

Kawamura, Masato*; Chishiro, Etsuji; Hori, Toshihiko; Shinozaki, Shinichi; Sato, Fumiaki; Fukui, Yuji*; Futatsukawa, Kenta*; Yamazaki, Masayoshi*; Sagawa, Ryu*; Yukitake, Mitsuteru*; et al.

Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1243 - 1247, 2013/08

no abstracts in English

Journal Articles

High-power test and thermal characteristics of a new radio-frequency quadrupole cavity for the Japan Proton Accelerator Research Complex linac

Kondo, Yasuhiro; Morishita, Takatoshi; Hasegawa, Kazuo; Chishiro, Etsuji; Hirano, Koichiro; Hori, Toshihiko; Oguri, Hidetomo; Sato, Fumiaki; Shinozaki, Shinichi; Sugimura, Takashi*; et al.

Physical Review Special Topics; Accelerators and Beams, 16(4), p.040102_1 - 040102_8, 2013/04

 Times Cited Count:9 Percentile:36.65(Physics, Nuclear)

We performed a high-power test of a new radio-frequency quadrupole (RFQ II) for the J-PARC linac. RFQ II was developed as a spare RFQ because the operating J-PARC RFQ has suffered from a sparking problem. First, the conditioning of RFQ II was carried out; after 50 h of conditioning, RFQ II became very stable with a nominal power and duty of 330 kW and 3%, respectively. Next the thermal properties were measured because the resonant frequency of RFQ II is tuned by changing the temperature of the cooling water. The frequency response was measured and compared to finite-element method simulation results, confirming that the simple two-dimensional model reproduces the experimental data well. The differences in the field distribution with changes in the rf loading and the cooling-water temperature were also measured, and no serious field distortion was observed. Therefore, we conclude that RFQ II can perform well as a high-power rf cavity.

Journal Articles

Present status of RF source in J-PARC linac; Recovery from earthquake disaster and energy upgrade

Kawamura, Masato*; Chishiro, Etsuji; Shinozaki, Shinichi; Fang, Z.*; Fukui, Yuji*; Naito, Fujio*; Yamazaki, Masayoshi*; Tsubota, Naoaki; Futatsukawa, Kenta; Sato, Fumiaki; et al.

Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 3 Pages, 2011/08

We will report about status of linac 400 MeV upgrade program and northeast Japan earthquake restoration. On March 11, the linac suffered serious damage as consequence of the earthquake, and was shuttled down for long term. Linac RF group restores the facilities and is accomplishing 400 MeV upgrade at the same time.

Journal Articles

Upgrade of the RF reference system for the J-PARC 400 MeV LINAC

Futatsukawa, Kenta; Fang, Z.*; Kobayashi, Tetsuya*; Fukui, Yuji*; Shinozaki, Shinichi

Proceedings of 8th Annual Meeting of Particle Accelerator Society of Japan (Internet), 4 Pages, 2011/08

A new RF reference signal oscillator, which can provide signals of not only 312 MHz signal but also 960 MHz in synchronism with the 12 MHz J-PARC master clock, was installed at J-PARC LINAC for the 400 MeV upgrade. The phase noise of the output signal in this module was measured by the signal source analyzer. The jitter of the output signal, which was estimated from the integration of phase noise from 10 Hz to 1 MHz, becomes about 240 fsec and was one order smaller than that of the old system (about 1700 fsec). However, the original performance of this module is expected to be better. It's thought to be due to the 12 MHz input signal in this module. Therefore, the path of the 12 MHz master clock was optimized except for unnecessary modules. In addition, necessary modules, the O/E and E/O modules, were selected for the less phase noise in some kind of modules with the same features. Then, the jitter of the output signal in the RF reference signal oscillator improved to be about 41 fsec, which is less than one fifth that before the optimization. This value satisfies the required phase stability ($$pm$$ 0.3$$^{circ}$$). Moreover, the high-accuracy synchronism of two kinds of frequency, 324 MHz and 972 MHz, was confirmed by the sampling oscilloscope. Therefore the RF reference signal with more precision can be provided by this system after the upgrade.

Journal Articles

Power supply system for klystron in J-PARC linac

Kawamura, Masato*; Fukui, Yuji*; Naito, Fujio*; Chishiro, Etsuji; Yamazaki, Masayoshi*; Suzuki, Hiroyuki*; Shinozaki, Shinichi; Hasegawa, Kazuo

Proceedings of 25th International Linear Accelerator Conference (LINAC 2010) (CD-ROM), p.887 - 889, 2010/09

This paper describes the present status, technical specifications, operating experience, and upgrade plane for the power supply system (PS system) for the klystrons in the J-PARC. The PS systems include both the high voltage DC power supplies (DCPSs), which drives one or four modulating-anode klystron each, and the anode-modulators, one per klystron. Currently, the energy output of the J-PARC linac is 181 MeV, which includes the energy necessary to run twenty 324 MHz klystrons. In 2012, the linac will add twenty-five 972 MHz klystrons and upgrade the energy output to 400 MeV.

Journal Articles

Development of LLRF control software for the J-PARC 400 MeV Linac

Fang, Z.*; Michizono, Shinichiro*; Anami, Shozo*; Yamaguchi, Seiya*; Naito, Fujio*; Fukui, Yuji*; Kobayashi, Tetsuya; Suzuki, Hiroyuki; Chishiro, Etsuji; Shinozaki, Shinichi

Proceedings of 7th Annual Meeting of Particle Accelerator Society of Japan (DVD-ROM), p.1068 - 1070, 2010/08

The output energy of the J-PARC proton Linac will be upgraded from 181 to 400 MeV in the next two years by adding 972-MHz high-beta acceleration sections. The RF signals are controlled by the FPGA-based digital feedback control systems installed in a compact PCI (cPCI). Recently, the LLRF control software has also been upgraded for the J-PARC Linac, especially for the 972-MHz high-beta systems. Many functions have been added to the LLRF control software, such as (1) gradually increasing the feedback gains in the feedback loop instead of fixed ones, (2) automatic chopped-beam compensation, (3) automatically switching the beam loading compensation in accordance with the different beam operation mode, (4) input RF-frequency tuning carried out by a FPGA to match the RF cavities during the RF start-up, (5) auto-tuning of the RF cavity tuner by detecting the phase curve of the RF cavity during the field decay instead of the phase difference between the cavity input and output signals.

Journal Articles

LLRF controller upgrade for the J-PARC 400 MeV linac

Fang, Z.*; Michizono, Shinichiro*; Anami, Shozo*; Yamaguchi, Seiya*; Naito, Fujio*; Fukui, Yuji*; Kawamura, Masato*; Kubota, Chikashi*; Nammo, Kesao*; Kobayashi, Tetsuya; et al.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.1434 - 1436, 2010/05

The output energy of the J-PARC proton linac will be upgraded from 181 to 400 MeV in the next two years by adding high-b acceleration sections. The upgrade of the FPGA-based digital LLRF controller for the 400 MeV linac will be presented in this paper. This new LLRF controller works for both the 324-MHz low-b and 972-MHz high-b sections. Many functions have been added into the LLRF controller, such as (1) working for different RF systems, (2) gradually increasing the feedback gains in the feedback loop instead of fixed ones, (3) automatic chopped beam compensation, (4) automatically switching the beam loading compensation in accordance with different beam operation mode, (5) input RF-frequency tuning to match the RF cavities during RF start-up, and (6) auto-tuning of the RF cavity tuner by detecting the phase curve of the RF cavity during the field decay instead of the phase difference between the cavity input and output signals.

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