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Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Aratani, Hidekazu*; Nakatani, Yasuhiro*; Fujiwara, Hidenori*; Kawada, Moeki*; Kanai, Yuina*; Yamagami, Kohei*; Fujioka, Shuhei*; Hamamoto, Satoru*; Kuga, Kentaro*; Kiss, Takayuki*; et al.
Physical Review B, 98(12), p.121113_1 - 121113_6, 2018/09
Times Cited Count:5 Percentile:25.53(Materials Science, Multidisciplinary)Nagai, Kodai*; Fujiwara, Hidenori*; Aratani, Hidekazu*; Fujioka, Shuhei*; Yomosa, Hiroshi*; Nakatani, Yasuhiro*; Kiss, Takayuki*; Sekiyama, Akira*; Kuroda, Fumiaki*; Fujii, Hitoshi*; et al.
Physical Review B, 97(3), p.035143_1 - 035143_8, 2018/01
Times Cited Count:22 Percentile:69.75(Materials Science, Multidisciplinary)We have studied the electronic structure of ferrimagnetic MnVAl single crystals by means of soft X-ray absorption spectroscopy (XAS), X-ray absorption magnetic circular dichroism (XMCD), and resonant soft X-ray inelastic scattering (RIXS). We have successfully observed the XMCD signals for all the constituent elements. The Mn L XAS and XMCD spectra are reproduced by spectral simulations based on density-functional theory, indicating the itinerant character of the Mn 3 states. On the other hand, the V 3 electrons are rather localized since the ionic model can qualitatively explain the V L XAS and XMCD spectra. This picture is consistent with local excitations revealed by the V L RIXS.
Tsukuda, Satoshi*; Takahashi, Ryota*; Seki, Shuhei*; Sugimoto, Masaki; Idesaki, Akira; Yoshikawa, Masahito; Tanaka, Shunichiro*
Radiation Physics and Chemistry, 118, p.16 - 20, 2016/01
Times Cited Count:1 Percentile:10.6(Chemistry, Physical)Polyvinylpyrrolidone (PVP)-Pt nanoparticles (NPs) hybrid nanowires were fabricated by high energy ion beam irradiation to PVP thin films including HPtCl. Single ion hitting caused crosslinking reactions of PVP and reduction of Pt ions within local cylindrical area along an ion trajectory (ion track); therefore, the PVP nanowires including Pt NPs were formed and isolated on Si substrate after wet-development procedure. The number of Pt NPs was easily controlled by the mixed ratio of PVP and HPtCl. However, increasing the amount of HPtCl led to decreasing the radial size and separation of the hybrid nanowires during the wet-development. Additional electron beam irradiation after ion beam improved separation of the nanowires and controlled radial sizes due to an increase in the density of crosslinking points inner the nanowires.
Sakoda, Masahito*; Kubota, Kazuhiro*; Tanaka, Shuhei*; Matsuoka, Eiichi*; Sugawara, Hitoshi*; Matsuda, Tatsuma; Haga, Yoshinori
Journal of the Physical Society of Japan, 81(Suppl.B), p.SB011_1 - SB011_4, 2012/12
Times Cited Count:2 Percentile:19.22(Physics, Multidisciplinary)Sakoda, Masahito*; Tanaka, Shuhei*; Matsuoka, Eiichi*; Sugawara, Hitoshi*; Harima, Hisatomo*; Honda, Fuminori*; Settai, Rikio*; Onuki, Yoshichika; Matsuda, Tatsuma; Haga, Yoshinori
Journal of the Physical Society of Japan, 80(8), p.084716_1 - 084716_5, 2011/08
Times Cited Count:8 Percentile:50.6(Physics, Multidisciplinary)Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki*; Shimomura, Takuya; Sasao, Hajime*; Tanaka, Momoko; Ochi, Yoshihiro; Tanoue, Manabu*; Kondo, Shuji; Kanazawa, Shuhei; et al.
Reza Kenkyu, 38(9), p.669 - 675, 2010/09
This paper reviews the temporal contrast and spatial beam quality improvement techniques in a high intensity Ti:sapphire laser system that is based on chirped-pulse amplification (CPA). We describe a low gain optical parametric chirped-pulse amplification (OPCPA) preamplifier that uses high energy, clean pulse seeding and is shown to significantly improve the contrast to better than 10-10 relative to the peak of the main femtosecond pulse. We also report the use of a diffractive optical element for beam homogenization of a 100 J level Nd:glass green pump laser, achieving a flat-topped spatial profile with a filling factor near 80 %.
Kosuge, Atsushi; Kiriyama, Hiromitsu; Shimomura, Takuya*; Tanoue, Manabu*; Kanazawa, Shuhei; Ochi, Yoshihiro; Mori, Michiaki; Tanaka, Momoko; Okada, Hajime; Sasao, Hajime*; et al.
Reza Kenkyu, 38(9), p.706 - 710, 2010/09
High conversion efficiency of optical parametric chirped-pulse amplification (OPCPA) is demonstrated with the use of a commercial frequency-doubled Q-Switched Nd:YAG laser. In the high energy seeded OPCPA, we have achieved a pump-to-signal conversion efficiency of 28%. Our result represents, to our knowledge, the most efficient OPCPA to date pumped by a commercial frequency-doubled Q-switched Nd:YAG laser.
Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Sasao, Hajime; Tanaka, Momoko; Ochi, Yoshihiro; Tanoue, Manabu*; Okada, Hajime; Kondo, Shuji; et al.
JAEA-Conf 2010-002, p.18 - 21, 2010/06
We have developed a femtosecond high intensity laser system, which combines both Ti:sapphire chirped-pulse amplification (CPA) and optical parametric chirped-pulse amplification (OPCPA) techniques, that produces more than 30 J broadband output energy, indicating the potential for achieving peak powers in excess of 500 TW. With a cleaned high-energy seeded OPCPA preamplifier as a front-end in the system, for the final compressed pulse (without pumping the booster amplifier) we found that the temporal contrast in this system exceeds 10 on the sub-nanosecond timescale, and is near 10 on the nanosecond timescale before the main femtosecond pulse. Using diffractive optical elements for beam homogenization of 100-J level high-energy Nd:glass green pump laser in a Ti:sapphire final amplifier, we have successfully generated broadband high-energy output with near-perfect top-hat intensity distributions.
Tsukuda, Satoshi*; Asano, Atsushi*; Sugimoto, Masaki; Idesaki, Akira; Seki, Shu*; Tanaka, Shunichiro*
Journal of Photopolymer Science and Technology, 23(2), p.231 - 234, 2010/06
Times Cited Count:0 Percentile:0.01(Polymer Science)The nanowires based on polystyrene (PS) and polycarbosilane (PCS) were formed by 450 MeV Xe beam irradiation to their thin films. The nanowires, which formed by crosslinking reaction along the single ion path, can isolated by development procedures. This technique is sometimes called as single particle nanofabrication technique (SPNT). In this paper, tow step irradiation of ion beam and ray was carried out in order to control their radial sizes. The radial sizes of nanowires, based on PS and PCS were increased with the dose of ray. The change of radial sizes, which depended on the dose, was quantitatively measured, and we discussed in terms of radiation induced gel formation.
Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Sasao, Hajime; Tanaka, Momoko; Ochi, Yoshihiro; Tanoue, Manabu*; Okada, Hajime; Kondo, Shuji; et al.
Applied Optics, 49(11), p.2105 - 2115, 2010/04
Times Cited Count:39 Percentile:83.63(Optics)We have developed a femtosecond high intensity laser system, which combines both Ti:sapphire chirped-pulse amplification (CPA) and optical parametric chirped-pulse amplification (OPCPA) techniques, that produces more than 30-J broadband output energy, indicating the potential for achieving peak powers in excess of 500-TW. With a cleaned high-energy seeded OPCPA preamplifier as a front-end in the system, for the compressed pulse without pumping the final amplifier we found that the temporal contrast in this system exceeds 10 on the sub-nanosecond timescales, and is near 10 on the nanosecond timescale prior to the peak of the main femtosecond pulse. Using diffractive optical elements for beam homogenization of 100-J level high-energy Nd:glass green pump laser in a Ti:sapphire final amplifier, we have successfully generated broadband high-energy output with a near-perfect top-hat-like intensity distribution.
Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya*; Tanoue, Manabu*; Okada, Hajime; Sasao, Hajime; Wakai, Daisuke*; Kondo, Shuji; Kanazawa, Shuhei; et al.
JAEA-Conf 2009-007, p.97 - 100, 2010/03
no abstracts in English
Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Tanoue, Manabu*; Okada, Hajime; Kondo, Shuji; Kanazawa, Shuhei; Sagisaka, Akito; Daito, Izuru; et al.
AIP Conference Proceedings 1153, p.3 - 6, 2009/07
We demonstrate a high-contrast, high-intensity double chirped-pulse amplification (CPA) Ti:sapphire laser system using an optical parametric chirped-pulse amplifier (OPCPA) as a preamplifier. By injecting cleaned microjoule seed pulses into the OPCPA, a temporal contrast greater than 10 within picosecond times before the main femtosecond pulse is demonstrated with the output pulse energy of 1.7 J and pulse duration of 30 fs, corresponding to a peak power of 60 TW at a 10 Hz repetition rate. This system uses a cryogenically-cooled Ti:sapphire final amplifier and generates focused peak intensities in excess of 10 W/cm.
Kiriyama, Hiromitsu; Tanaka, Momoko; Ochi, Yoshihiro; Nakai, Yoshiki; Sasao, Hajime; Okada, Hajime; Mori, Michiaki; Shimomura, Takuya; Kanazawa, Shuhei; Daido, Hiroyuki; et al.
Reza Kenkyu, 37(6), p.467 - 469, 2009/06
The capability of diffractive optical elements (DOE) for beam homogenization of 100-J level high-energy Nd:glass green laser has been experimentally demonstrated. With the large-aperture homogenization optics, we have successfully generated near-perfect top-hat-like green beam intensity distributions at the target plane. The output of the system is readily suited for pumping a large-aperture Ti:sapphire crystal, making it possible to develop high beam quality, chirped-pulse amplification (CPA) systems at the petawatt (PW) power level.
Oki, Shigeo; Ogawa, Takashi; Kobayashi, Noboru; Naganuma, Masayuki; Kawashima, Katsuyuki; Maruyama, Shuhei; Mizuno, Tomoyasu; Tanaka, Toshihiko*
Proceedings of International Conference on the Physics of Reactors, Nuclear Power; A Sustainable Resource (PHYSOR 2008) (CD-ROM), 10 Pages, 2008/09
Conceptual design studies of sodium-cooled fast reactor core are performed in Fast Reactor Cycle Technology Development Project (FaCT Project) in Japan. The representative MOX fuel core and the metal fuel core exert excellent performances on safety and reliability, sustainability, economic competitiveness, and nuclear non-proliferation. This paper reviews their feature in terms of reactor physics, and describes recent progress in design studies. In the recent design studies, much interest has been taken in the fuel composition change in the transition stage from light water reactors to fast breeder reactors. The core flexibility is also shown to fulfil the refined objectives such as high breeding and an enhancement of non-proliferation property.
Tsukuda, Satoshi*; Seki, Shuhei*; Tagawa, Seiichi*; Sugimoto, Masaki; Idesaki, Akira; Tanaka, Shigeru; Oshima, Akihiro*
Journal of Physical Chemistry B, 108(11), p.3407 - 3409, 2004/03
Times Cited Count:51 Percentile:71.91(Chemistry, Physical)Nano-wire formation in Si-based polymer thin films using a heavy ion beam is discussed in terms of energy density deposition along ion tracks. Gelation of the polymer along the ion track results in cross-linking to produce nano-wires with size and number density controllable by selecting appropriate ion beam characteristics and polymer materials. Ion bombardment of polycarbosilane (PCS), PCS-polyvinylsilane blend polymer, and polymethylphenylsilane produces nano-wires with radii of 30 nm depending on the type of ion beam. The difference in size is shown to be related to the efficiency of the cross-linking reaction considering the deposited energy distribution along the ion tracks.
Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Tanoue, Manabu*; Okada, Hajime; Kondo, Shuji; Kanazawa, Shuhei; Sagisaka, Akito; Daito, Izuru; et al.
no journal, ,
We demonstrated laser peak intensity above 10W/cm and temporal contrast exceeding 10 at a 10 Hz repetition rate with a 60 TW, 30 fs laser (J-KAREN laser). Here we report the upgrade of the J-KAREN laser to the petawatt peak power level. This is accomplished by adding a Ti:sapphire booster amplifier downstream of the final amplifier chain of the 60 TW J-KAREN laser system. Stretched pulses of energy 3 J from the previous J-KAREN laser are up-collimated and introduced into the final booster amplifier. The booster amplifier consists of a large-aperture Ti:sapphire crystal pumped by a frequency-doubled Nd:silicate glass laser with pulse energy 60 J. Diffractive optical elements are used for pump beam homogenization to maintain a uniform spatial profile and reliable, damage-free operation. The system produces an uncompressed output pulse energy exceeding 30 J with a near homogeneous flat-top spatial distribution, indicating potential peak power of 500 TW.
Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Tanoue, Manabu*; Okada, Hajime; Kondo, Shuji; Kanazawa, Shuhei; Sagisaka, Akito; Daito, Izuru; et al.
no journal, ,
We have demonstrated over 30 J broadband output energy based on optical parametric chirped-pulse amplification (OPCPA) and Ti:sapphire chirped-pulse amplification (CPA), indicating potential for peak power of 500 TW with extremely high temporal contrast.
Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Sasao, Hajime; Tanaka, Momoko; Ochi, Yoshihiro; Tanoue, Manabu*; Okada, Hajime; Kondo, Shuji; et al.
no journal, ,
We have developed a femtosecond high intensity laser system, which combines both Ti:sapphire chirped-pulse amplification (CPA) and optical parametric chirped-pulse amplification (OPCPA) techniques, that produces more than 30 J broadband output energy, indicating the potential for achieving peak powers in excess of 500 TW. With a cleaned high-energy seeded OPCPA preamplifier as a front-end in the system, for the final compressed pulse we found that the temporal contrast in this system exceeds 10 on the sub-nanosecond timescale before the main femtosecond pulse. Using diffractive optical elements for beam homogenization of 100-J level high-energy Nd:glass green pump laser in a Ti:sapphire final amplifier, we have successfully generated broadband high-energy output with near-perfect top-hat intensity distributions.
Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Sasao, Hajime; Tanaka, Momoko; Ochi, Yoshihiro; Tanoue, Manabu*; Okada, Hajime; Kondo, Shuji; et al.
no journal, ,
We have developed a femtosecond high intensity laser system, which combines both Ti:sapphire chirped-pulse amplification (CPA) and optical parametric chirped-pulse amplification (OPCPA) techniques, that produces more than 30 J broadband output energy, indicating the potential for achieving peak powers in excess of 500 TW. With a cleaned high-energy seeded OPCPA preamplifier as a front-end in the system, for the final compressed pulse we found that the temporal contrast in this system exceeds 10 on the sub-nanosecond timescale before the main femtosecond pulse. Using diffractive optical elements for beam homogenization of 100-J level high-energy Nd:glass green pump laser in a Ti:sapphire final amplifier, we have successfully generated broadband high-energy output with near-perfect top-hat intensity distributions.