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Yamano, Hidemasa; Takai, Toshihide; Emura, Yuki; Fukuyama, Hiroyuki*; Higashi, Hideo*; Nishi, Tsuyoshi*; Ota, Hiromichi*; Morita, Koji*; Nakamura, Kinya*; Fukai, Hirofumi*; et al.
Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-13) (Internet), 12 Pages, 2022/09
This paper describes the project overview and progress of experimental and analytical studies conducted until 2020. Specific results in this paper are the measurement of the eutectic reaction rates and the validation of physical model describing the eutectic reaction in the analysis code through the numerical analysis of the B
C-SS eutectic reaction rate experiments in which a BC pellet was placed in a SS crucible.
Kiriyama, Hiromitsu; Mori, Michiaki; Suzuki, Masayuki*; Daito, Izuru*; Okada, Hajime; Ochi, Yoshihiro; Tanaka, Momoko; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; et al.
Reza Kenkyu, 42(6), p.441 - 447, 2014/06
We describe three specific high power laser systems that are being developed in our laboratory for many applications in high field science, nonlinear optics and material processing. We report on a femtosecond petawatt-class Ti:sapphire chirped-pulse amplification laser system that can produce a pulse energy of 20 J of 40 fs pulse duration, a picosecond high intensity Yb:YAG chirped-pulse amplification laser system that can generate a pulse energy of 100 mJ of 0.5 ps pulse duration, and a nanosecond high repetition rate Nd:YAG laser system that can provide an average power of 360 W with a pulse duration of 30 ns delivered at a 1 kHz repetition rate. We discuss the basic design aspects and present the results from our experimental investigations of these laser systems.
Kiriyama, Hiromitsu; Shimomura, Takuya; Mori, Michiaki; Nakai, Yoshiki*; Tanoue, Manabu; Kondo, Shuji; Kanazawa, Shuhei; Pirozhkov, A. S.; Esirkepov, T. Z.; Hayashi, Yukio; et al.
Applied Sciences (Internet), 3(1), p.214 - 250, 2013/03
Times Cited Count：15 Percentile：50(Chemistry, Multidisciplinary)This paper reviews techniques for improving the temporal contrast and spatial beam quality in an ultra-intense laser system that is based on chirped-pulse amplification (CPA). We describe the design, performance, and characterization of our laser system, which has the potential for achieving a peak power of 600 TW. We also describe applications of the laser system in the relativistically dominant regime of laser-matter interactions and discuss a compact, high efficiency diode-pumped laser system.
Suzuki, Masayuki; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Ochi, Yoshihiro; Sato, Masatoshi*; Yoshii, Takehiro*; Tamaoki, Yoshinori*; Maeda, Junya*; Matsuoka, Shinichi*; et al.
AIP Conference Proceedings 1465, p.53 - 57, 2012/07
Times Cited Count：0 Percentile：0.13(Physics, Applied)We have reported hundred mJ level, femtosecond pulse duration with the high temporal contrast in an OPCPA/Yb:YAG ceramic thin disk laser system at 10 Hz repetition rate. At an input laser pulse energy of 3.8 mJ from the OPCPA preamplifer the output energy of 130 mJ with spectral bandwidth of 2.5 nm has been obtained from multipass Yb:YAG ceramic thin disk amplifier, and the optical efficiency from LD energy to amplified laser pulse is 9.6%. The recompressed laser pulse duration was measured to be 450 fs. Because the compressor efficiency exceeds 73% the compressed pulse energy can potentially be as high as 95 mJ. The contrast level of this laser pulse was measured to be less than 7.2
10
at -150 ps. This novel laser system after further amplification using additional amplifiers can be useful for the laser-driven proton acceleration in future.
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
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.
Suzuki, Masayuki*; Kiriyama, Hiromitsu; Daito, Izuru; Ochi, Yoshihiro; Okada, Hajime; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; Maeda, Junya*; Matsuoka, Shinichi*; et al.
Applied Physics B, 105(2), p.181 - 184, 2011/11
Times Cited Count：5 Percentile：28.65(Optics)We have demonstrated an OPCPA/Yb:YAG ceramic thin disk hybrid laser system having hundred mJ level pulse energy sub-picosecond pulse duration with high temporal contrast. At an input energy of 3.8 mJ from an OPCPA preamplifier an output energy of 130 mJ was obtained from Yb:YAG ceramic thin disk amplifier. A recompressed pulse duration of 450 fs with a contrast level of less than 7.210
was obtained. The contrast level is the highest value achieved in Yb:YAG chirped pulse amplification (CPA) laser system with hundred mJ level.
Suzuki, Masayuki; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Nakai, Yoshiki; Orimo, Satoshi; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; Maeda, Junya*; et al.
Applied Physics B, 97(2), p.379 - 382, 2009/10
Times Cited Count：7 Percentile：37.56(Optics)We report the highest energy broadband laser pulses at a center wavelength of 1030 nm based on optical parametric chirped-pulse amplification (OPCPA). We have demonstrated amplification of 1030 nm femtosecond laser pulses from a broadband Yb oscillator to over 6.5 mJ with a total gain of greater than 10
achieved in a single pass through only 56 mm of gain material at a 10 Hz repetition rate. The amplified spectral bandwidth of 10.8 nm affords recompression to a 230 fs pulse duration following amplification. As an alternative to the regenerative amplifier (RA) this system is one of the more promising candidates for realizing compact, high intensity, direct diode pumped, high repetition rate femtosecond Yb:YAG chirped-pulse amplification (CPA) in laser systems.
Kiriyama, Hiromitsu; Yamakawa, Koichi; Kageyama, Nobuto*; Miyajima, Hirofumi*; Kan, Hirofumi*; Yoshida, Hidetsugu*; Nakatsuka, Masahiro*
Japanese Journal of Applied Physics, Part 1, 44(10), p.7464 - 7471, 2005/10
Times Cited Count：2 Percentile：9.29(Physics, Applied)no abstracts in English
Maruyama, Yoichiro; Kubomura, Hiroyuki*; Kasamatsu, Tadashi*; Matsuoka, Shinichi*; Nakano, Fumihiko*; Kan, Hirofumi*
JAERI-Tech 2004-056, 14 Pages, 2004/09
JAERI-Tech-2004-056.pdf:3.49MB
A high average power tunable solid state laser is pumped by the second harmonic of LD-pumped high repetition rate Nd:YAG laser consisting of a single-longitudinal-mode oscillator and amplifiers. To operate the Nd:YAG laser oscillator with a single-longitudinal-mode by injection seeding, the cavity length control is required to coincide the resonant frequency of Nd:YAG laser oscillator with the frequency of seeder. For this purpose, a cavity length control system of the Nd:YAG laser oscillator is developed and the characteristics are studied. With this system, the cavity length is controlled at the pulse repetition rate of 0.5 kHz and the single frequency operation for more than three hours is realized.
Kiriyama, Hiromitsu; Yamakawa, Koichi; Nagai, Toru; Kageyama, Nobuto*; Miyajima, Hirofumi*; Kan, Hirofumi*; Yoshida, Hidetsugu*; Nakatsuka, Masahiro*
Optics Letters, 28(18), p.1671 - 1673, 2003/09
Times Cited Count：29 Percentile：74.02(Optics)no abstracts in English
Suzuki, Masayuki; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Sato, Masatoshi*; Matsuoka, Shinichi*; Yoshii, Takehiro*; Kan, Hirofumi*; Bolton, P.; Daido, Hiroyuki; et al.
no journal, ,
Muramatsu, Toshiharu; Shobu, Takahisa; Sato, Katsuhiko*; Maeda, Junya*; Kan, Hirofumi*
no journal, ,
no abstracts in English
Suzuki, Masayuki; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Sato, Masatoshi*; Yoshii, Takehiro*; Tamaoki, Yoshinori*; Maeda, Junya*; Matsuoka, Shinichi*; Kan, Hirofumi*; et al.
no journal, ,
We have demonstrated amplification of 1030 nm broadband chirped-pulses from an ytterbium (Yb) femtosecond oscillator to over 6.5 mJ with a total gain of greater than 10 achieved by a single pass through only 56 mm of gain material at a 10 Hz repetition rate. The amplified broad bandwidth of 10.8 nm affords recompression to a 230 fs pulse duration following amplification. This novel system is a promising alternative to the RA as a nonlinear preamplifier for compact, high intensity, Yb:YAG CPA laser using DPPSL systems.
Suzuki, Masayuki; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Nakai, Yoshiki; Orimo, Satoshi; Sato, Masatoshi*; Tamaoki, Yoshinori*; Yoshii, Takehiro*; Maeda, Junya*; et al.
no journal, ,
We have reported the demonstration of an optical parametric chirped-pulse amplification (OPCPA) operating at 1030 nm. A total OPCPA output energy of 6.5 mJ (uncompressed) with gain exceeding of 10 has been achieved with a spectral bandwidth of 10.8 nm and a recompressed pulse duration of 230 fs. This novel system is a promising alternative to the RA as a nonlinear preamplifier for compact, high intensity, Yb:YAG CPA laser using DPPSL systems.
Sato, Katsuhiko*; Maeda, Junya*; Kan, Hirofumi*; Shobu, Takahisa; Muramatsu, Toshiharu
no journal, ,
no abstracts in English
Suzuki, Masayuki; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Nakai, Yoshiki*; Daido, Hiroyuki; Bolton, P.; Sugiyama, Akira; Kondo, Kiminori; Kawanishi, Shunichi; et al.
no journal, ,
At our Institute we are developing a compact ion accelerator for cancer therapy using a laser-driven plasma point source of ions. The laser system was consisted of an oscillator, offner stretcher, optical parametric amplifier (OPCPA), LD pumped Yb:YAG amplifier, and compressor. In OPCPA the stretched laser pulse after the pulse stretcher was amplified to 5 mJ with only a 0.2 mJ input. After amplification in the OPCPA laser pulse was further amplified by an Yb:YAG (5 at%) thin disk module which was pumped by the Q-CW LD. The maximum output energy was about 120 mJ in a multi-pass scheme (20 pass) at 10 Hz. The compressed pulse duration is about 300 fs, and the contrast level before the main pulse is measured as 10 at -150 ps. We have developed that new high intensity, high contrast femtosecond OPCPA/LD-pumped Yb:YAG hybrid laser system. This novel system might represent the driver in integrated, laser-driven ion accelerator systems.
Suzuki, Masayuki; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Sato, Masatoshi*; Yoshii, Takehiro*; Tamaoki, Yoshinori*; Matsuoka, Shinichi*; Kan, Hirofumi*; Bolton, P.; et al.
no journal, ,
no abstracts in English
Suzuki, Masayuki; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Bolton, P.; Sugiyama, Akira; Kondo, Kiminori; Kawanishi, Shunichi*; Sato, Masatoshi*; Tamaoki, Yoshinori*; et al.
no journal, ,
At our Institute we are developing a compact ion accelerator for cancer therapy using a laser-driven plasma point source of ions. The laser system was consisted of an oscillator, Offner stretcher, optical parametric amplifier (OPCPA), LD pumped Yb:YAG amplifier, and compressor. In OPCPA the stretched laser pulse after the pulse stretcher was amplified to 3.8 mJ with only a 12.8 nJ input. After amplification in the OPCPA laser pulse was further amplified by an Yb:YAG thin disk module which was pumped by the Q-CW LD. The maximum output energy was about 80 mJ in a multi-pass scheme (20 pass) at 10 Hz. The compressed pulse duration is about 520 fs, and the contrast level before the main pulse is measured as 10 at -150 ps. We have developed that new high intensity, high contrast femtosecond OPCPA/LD-pumped Yb:YAG hybrid laser system. This novel system might represent the driver in integrated, laser-driven ion accelerator systems.
Kiriyama, Hiromitsu; Mori, Michiaki; Shimomura, Takuya; Nakai, Yoshiki*; Tanoue, Manabu*; Sasao, Hajime*; Kondo, Shuji; Kanazawa, Shuhei; Ochi, Yoshihiro; Tanaka, Momoko; et al.
no journal, ,
We report on a femtosecond high-intensity OPCPA/Ti:sapphire hybrid laser system that produces more than 30 J broadband output energy, indicating the potential for achieving petawatt-class peak powers. High temporal-contrast of 10
to 10
has been obtained with a near-perfect flat-topped spatial-profile of filling factor 80%. We also present a compact, high-intensity OPCPA/Yb:YAG hybrid laser system that generates 100 mJ output energy with a temporal contrast of better than 10 and good spatial beam quality.
Suzuki, Masayuki*; Kiriyama, Hiromitsu; Daito, Izuru; Okada, Hajime; Ochi, Yoshihiro; Sato, Masatoshi*; Yoshii, Takehiro*; Tamaoki, Yoshinori*; Maeda, Junya*; Matsuoka, Shinichi*; et al.
no journal, ,
no abstracts in English
