Effect of magnetism on lattice dynamics in SrFeAs using high-resolution inelastic X-ray scattering

Murai, Naoki*; Fukuda, Tatsuo; Kobayashi, Tatsuya*; Nakajima, Masamichi*; Uchiyama, Hiroshi*; Ishikawa, Daisuke*; Tsutsui, Satoshi*; Nakamura, Hiroki; Machida, Masahiko; Miyasaka, Shigeki*; et al.

Physical Review B, 93(2), p.020301_1 - 020301_5, 2016/01

https://doi.org/10.1103/PhysRevB.93.020301

Development of a compact high-spatiotemporal-quality Yb:YAG thin-disk laser system using an optical parametric preamplifier

Kiriyama, Hiromitsu; Suzuki, Masayuki*; Daito, Izuru; Okada, Hajime; Ochi, Yoshihiro; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; Maeda, Junya*; Matsuoka, Shinichi*; et al.

Reza Kenkyu, 40(2), p.143 - 145, 2012/02

http://ci.nii.ac.jp/naid/10030152656

We demonstrate a compact, high-spatiotemporal-quality, high-intensity diode-pumped Yb:YAG thin-disk chirped-pulse amplification (CPA) laser system that incorporates a nonlinear preamplifier based on optical parametric chirped-pulse amplification (OPCPA). The stretched pulses are amplified in the OPCPA preamplifier and the following Yb:YAG main amplifier to 100 mJ at 10 Hz. The broadband amplified beam quality of 1.1 (horizontal direction) and 1.4 (vertical direction) times diffraction limited and pulse compression down to 470 fs with contrast of better than 10 have been achieved successfully.

A Parameter study of pencil beam proton dose distributions for the treatment of ocular melanoma utilizing spot scanning

Sutherland, K.*; Miyajima, Satoshi*; Date, Hiroyuki*; Shirato, Hiroki*; Ishikawa, Masayori*; Murakami, Masao*; Yamagiwa, Mitsuru; Bolton, P.; Tajima, Toshiki

Radiological Physics and Technology, 3(1), p.16 - 22, 2010/01

https://doi.org/10.1007/s12194-009-0071-4

Measurement of DT and DD neutrons with a TOF spectrometer for determination of fuel ion density ratio in ITER

Okada, Koichi*; Kondo, Keitaro; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara; Okamoto, Atsushi*; Kobuchi, Takashi*; Kitajima, Sumio*; Sasao, Mamiko*

Journal of Plasma and Fusion Research SERIES, Vol.8, p.666 - 669, 2009/09

Measurement of fuel ion density ratio, /, is required for burning control on ITER. The measured / ratio must be fed back in real time. A neutron measurement system to measure / should be operable at high counting rate. It is estimated that the number of emitted DT neutrons is 200 times higher than that of DD neutrons under the condition of ITER standard operation. A neutron measurement system was developed using a DT/DD generator, where DT neutrons are dominant and DD neutrons are contaminated slightly in the neutron beam. The measurement instrument was a TOF spectrometer. Signals originating from each neutron must be distinguished in order to measure the fuel ratio. We developed a circuit system with discrimination windows to distinguish each signal pulse, and DT and DD neutrons were measured separately and simultaneously with this system. The experimental result indicates a possibility that this system is suitable for measurement of fuel ion density ratio on ITER.

Radiotherapy using a laser proton accelerator

Murakami, Masao*; Hishikawa, Yoshio*; Miyajima, Satoshi*; Okazaki, Yoshiko; Sutherland, K.*; Abe, Mitsuyuki*; Bulanov, S. V.; Daido, Hiroyuki; Esirkepov, T. Z.; Koga, J. K.; et al.

AIP Conference Proceedings 1024, p.275 - 300, 2008/08

https://doi.org/10.1063/1.2958203

no abstracts in English

Laser ion acceleration via control of the near-critical density target

Yogo, Akifumi; Daido, Hiroyuki; Bulanov, S. V.; Nemoto, Koshichi*; Oishi, Yuji*; Nayuki, Takuya*; Fujii, Takashi*; Ogura, Koichi; Orimo, Satoshi; Sagisaka, Akito; et al.

Physical Review E, 77(1), p.016401_1 - 016401_6, 2008/01

https://doi.org/10.1103/PhysRevE.77.016401

The duration-controlled amplified spontaneous emission with intensity of W/cm is used to convert a 7.5 m thick polyimide foil into a near-critical plasma, in which the -polarized, 45 fs, W/cm laser pulse generates 3.8 MeV protons, emitted at some angle between the target normal and the laser propagation direction of 45. Particle-in-cell simulations reveal that the efficient proton acceleration is due to generation of the quasistatic magnetic field on the target rear side with the magnetic pressure inducing and sustaining a charge separation electrostatic field.

High-resolution beam energy-spread measurements using combination of nuclear resonant reactions and a 0 beam line separation

Ishii, Yasuyuki; Chiba, Atsuya; Uno, Sadanori; Saito, Yuichi; Mizuhashi, Kiyoshi; Tajima, Satoshi*; Kamiya, Tomihiro

Nuclear Instruments and Methods in Physics Research B, 260(1), p.15 - 19, 2007/07

https://doi.org/10.1016/j.nimb.2007.01.273

Measurement of beam energy spreads caused by an accelerator are needed to evaluation the choromatic aberration when ion beams with micorometer or nanometer sizes are formed at a focusing point. A measurement method of the beam energy spreads without using a analyzing magnet with a high resolution was developed to evaluate the chromatic aberration in a light-ion micorbeam system connected to the 3MV JAEA single-ended accelerator. The accurate beam energy spread measurement method within a resolution of 10 was developed using resonance nuclear reactions with narrow energy spreads of A(p,)Si and Mg(p,)A in a MeV energy range. Furthermore, ion species separating method, in a 0-degree beam line connected to the accelerator, was developed using parmanent magnets attached on the accelerator tube in the accelerator. The two kinds of developmet resulted in measuring baem energy spreads generated from the accelerator directly.

Development of laser driven proton sources and their applications

Daido, Hiroyuki; Sagisaka, Akito; Ogura, Koichi; Orimo, Satoshi; Nishiuchi, Mamiko; Mori, Michiaki; Ma, J.-L.; Pirozhkov, A. S.; Kiriyama, Hiromitsu; Kanazawa, Shuhei; et al.

Proceedings of 7th Pacific Rim Conference on Lasers and Electro-Optics (CLEO-PR 2007) (CD-ROM), p.77 - 79, 2007/00

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4391143

We are developing a proton accelerator using an intense lasers with a focused intensity of 10 W/cm. To monitor proton energy spectra as well as plasma parameters at each laser shot, we are using real time detectors. The proton energy of MeV is stably obtained for applications.

Measurement of carbon cluster charge state passing through thin foils using a luminance plate

Chiba, Atsuya; Saito, Yuichi; Tajima, Satoshi

Nuclear Instruments and Methods in Physics Research B, 232(1-4), p.32 - 36, 2005/05

https://doi.org/10.1016/j.nimb.2005.03.021

The structure of cluster ion may be important parameter for resolution of physical effect and interaction with cluster ion and solid. In this paper, we report a Coulomb explosion imaging of the constituent atoms of a swift carbon cluster (Cn, n=2, 3 and 6) passing through a thin foil and their average charge state that related with the structure of the cluster. The experimental setup is based on the 3MV TANDEM accelerator at the JAERI Takasaki. The cluster ion beam is pulsed by electrical deflection plates and an aperture. A few clusters pass trough the thin foil during 1 second, and the resulting are collected by the luminance plate detector. The average charge state was shown an almost same tendency as calculate theoretical value.

Operation and maintenance for JAERI AVF cyclotron system

Nakamura, Yoshiteru; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Kurashima, Satoshi; Fukuda, Mitsuhiro; Okumura, Susumu; Yokota, Wataru; Arakawa, Kazuo; Miyawaki, Nobumasa; et al.

KEK Proceedings 2003-19, p.8 - 13, 2004/03

Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) facility at JAERI Takasaki was constructed to promote the various researches of wide field for materials science and biotechnology. The AVF cyclotron system, which is the one of four ion accelerators in TIARA, has been smoothly operated without any serious troubles since the first beam extraction in March 1991. The operation time for a year is about 3200 hours on an average through recent 8 years. In especial, the cyclotron system is needed the frequent alteration of operation condition according to many kinds of ion species required from the experimenters. On the other hand, because of the improvement of the beam quality, intensity and reliability, we have carried out continuously so far many reconstruction and development, several items of which are the renewal of a computer control system, reinforcement of the ion source, acceleration technique for some series of cocktail beams, stabilization of the cyclotron beam and design of a new gradient corrector including an active coil. Furthermore, now we are advancing various countermeasure to form the micro beam of 1mm size by means of focused type, such as the introduction of a flat-top acceleration system, reconstruction of the cyclotron center region, installation of a pair of precise micro slit systems in the trunk beam transport line, and so on.