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Kitamura, Akihisa*; Okazaki, Sota*; Kondo, Mitsuru*; Watanabe, Takahiro; Nakanishi, Toshimichi*; Hori, Rie*; Ikeda, Masayuki*; Ichimura, Koji*; Nakagawa, Yuki*; Mori, Hideki*
Shizuoka Daigaku Chikyu Kagaku Kenkyu Hokoku, (49), p.73 - 86, 2022/07
On July 3 2021, a debris flow caused by a landslide from a landfill occurred along the Aizome River in the Izusan area of Atami City, Shizuoka. In this study, debris flow deposits and soil samples were characterized in terms of their sedimentology and geochemically analyzed.
Kiriyama, Hiromitsu; Mori, Michiaki; Okada, Hajime; Shimomura, Takuya; Nakai, Yoshiki*; Tanoue, Manabu; Kondo, Shuji; Kanazawa, Shuhei; Yogo, Akifumi; Sagisaka, Akito; et al.
JPS Conference Proceedings (Internet), 1, p.015095_1 - 015095_5, 2014/03
We present the design and characterization of a high-contrast, petawatt-class Ti:sapphire chirped-pulse amplification (CPA) laser system. Two saturable absorbers and low-gain optical parametric chirped-pulse amplification (OPCPA) preamplifier in the double CPA laser chain have improved the temporal contrast to 1.4
10
on the subnanosecond time scale at 70 terawatt level. Final uncompressed broadband pulse energy is 28 J, indicating the potential for reaching peak power near 600 terawatt. We also discuss our upgrade to over petawatt level at a 0.1 Hz repetition rate briefly.
Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*
Progress in Photovoltaics; Research and Applications, 21(7), p.1499 - 1506, 2013/11
Times Cited Count：7 Percentile：29.39(Energy & Fuels)Proton degradation behaviors of hydrogenated amorphous silicon (a-Si:H) solar cells irradiated with protons at 331 K are compared with that at 298 K (room temperature). Variations with time in the post-irradiation electrical properties are also investigated. It is found that the radiation degradation of the electrical properties at 331 K is significantly smaller than that at room temperature. Also, all the electrical properties (short-circuit current, open-circuit voltage, output maximum, and fill factor) recover with time after irradiation even at room temperature. The characteristic time of thermal annealing of short-circuit current is larger as the temperature is higher. These results indicate that temperature during irradiation and elapsed time from irradiation to measurement is an important parameter for radiation degradation of a-Si:H solar cells. Therefore, these parameters should be controlled in conducting the ground radiation tests.
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：47.32(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.
Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*
Journal of Non-Crystalline Solids, 358(17), p.2039 - 2043, 2012/09
Times Cited Count：5 Percentile：30.04(Materials Science, Ceramics)Electrical conductivity variations of undoped, n-type and p-type hydrogenated amorphous silicon (a-Si:H) thin films irradiated with various energy protons are systematically investigated in this study. Dark conductivity (DC) and photoconductivity (PC) of the undoped samples increased at first due to proton irradiation and then decrease dramatically with increasing proton fluence. However, increased PC was metastable and gradually decreased with time. Similar results were observed in the n-type a-Si:H, whereas the monotonic decrease was observed in the p-type one. The degrees of the DC and the PC decreases became lower as the irradiated proton energy was higher. The increases of both DC and PC are attributed to the temporal donor like center generation, although the additional proton irradiation decrease both the DC and PC by the accumulation of radiation-induced defects, which are act as deep traps and compensate carriers.
Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*
Nuclear Instruments and Methods in Physics Research B, 286, p.29 - 34, 2012/09
Times Cited Count：8 Percentile：50.48(Instruments & Instrumentation)Electric conductivity variations of undoped hydrogenated amorphous silicon (a-Si:H) semiconductors induced by swift protons are investigated. The results show that the conductivity drastically increases at first and then decreases on further irradiation. The conductivity enhancement observed only in the low fluence regime lasts for a prolonged period of time when proton irradiation stops in this fluence regime. On the other hand, the photosensitivity has a minimum value around the conductivity peak. This fact indicates that non-equilibrium carriers do not play a dominant role in the electric conduction in this fluence regime. It is found that the anomalous conductivity enhancement is dominated by donor center generation in the low fluence regime. At higher fluences the variation in electric conductivity becomes dominated by non-equilibrium carriers as the generated donor centers disappear. This is a general interpretation of radiation induced conductivity in semiconductors.
Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*
Nuclear Instruments and Methods in Physics Research B, 285, p.107 - 111, 2012/08
Times Cited Count：6 Percentile：41.24(Instruments & Instrumentation)Kiriyama, Hiromitsu; Shimomura, Takuya; Sasao, Hajime; Nakai, Yoshiki*; Tanoue, Manabu; Kondo, Shuji; Kanazawa, Shuhei; Pirozhkov, A. S.; Mori, Michiaki; Fukuda, Yuji; et al.
Optics Letters, 37(16), p.3363 - 3365, 2012/08
Times Cited Count：40 Percentile：85.03(Optics)We demonstrate the temporal contrast enhancement in a petawatt-class Ti:sapphire chirped-pulse amplification (CPA) laser system. An extra saturable absorber, introduced downstream a low gain optical parametric chirped-pulse amplification (OPCPA) preamplifier, has improved the temporal contrast in the system to 1.410 on the sub-nanosecond time scale at 70 TW power level. We have achieved 28 J of uncompressed broadband output energy with this system, indicating the potential for reaching peak powers near 600 TW.
Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*
Applied Physics Express, 4(6), p.061401_1 - 061401_3, 2011/06
Times Cited Count：9 Percentile：36.77(Physics, Applied)Seebeck coefficient variations of undoped hydrogenated amorphous silicon (a-Si:H) semiconductors due to swift proton irradiation were investigated using an in-situ thermoelectric power measurement system. Undoped a-Si:H irradiated with 3.0 MeV protons at a fluence regime of 3.110
- 5.010/cm
showed a negative Seebeck coefficient although the Seebeck effect was not observed at fluences above 5.310
/cm. These results suggest that donor like centers are generated by low fluence proton irradiation, whereas the donor centers are compensated by radiation-induced defects or themselves disappear after high fluence proton irradiation. These effects decay with time, giving the donor centers a temporal nature.
Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*
Proceedings of 37th IEEE Photovoltaic Specialists Conference (PVSC-37) (CD-ROM), p.001615 - 001619, 2011/06
Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*
Proceedings of 9th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-9), p.183 - 186, 2010/10
Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*
Journal of Non-Crystalline Solids, 356(41-42), p.2114 - 2119, 2010/09
Times Cited Count：13 Percentile：55.89(Materials Science, Ceramics)Photoconductivity (PC) variations of device-grade a-Si:H thin films due to proton irradiation are investigated in this paper. We performed in-situ measurements of the PC variations induced by 0.10, 1.0 and 10 MeV proton irradiations. The irradiation initially caused an increase in PC in all sample. However, continued irradiation resulted in a dramatic decrease as the irradiation fluence increased. The results obtained in this study suggest that the PC increment is caused not by accumulation of displacement damage. The results of the temperature dependence of PC for a-Si:H before and after 10 MeV proton irradiation showed that such a proton-induced PC increment consisted of two components: one thermally stable and one metastable. The thermally metastable component disappeared in the temperature region of 300 to 340 K. On the contrary, radiation-induced defects were annealed above 340 K.
Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*
Proceedings of 35th IEEE Photovoltaic Specialists Conference (PVSC-35) (CD-ROM), p.002620 - 002624, 2010/06
Times Cited Count：2 Percentile：69.86(Energy & Fuels)Sato, Shinichiro; Sai, Hitoshi*; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*; Oshima, Takeshi
Proceedings of 34th IEEE Photovoltaic Specialists Conference (PVSC-34) (CD-ROM), p.002354 - 002358, 2009/06
Photoconductivity (PC) variations of a-Si:H thin films irradiated with 0.10, 1.0 or 10 MeV protons were investigated. According to the results, the PC values of all samples once increased and after that decreased dramatically. In order to obtain the knowledge about the anomalous PC increment, time dependence of the PC value increased by 10 MeV proton irradiation was also investigated. As a result, even the PC value after 270 hours was over twice higher than that before the irradiation, though the PC values decreased with time. However, the PC value became almost equivalent to the PC before the proton irradiation by applying light-soaking. These results mean that the anomalous PC increment is metastable.
Kando, Masaki; Masuda, Shinichi; Zhidkov, A.*; Yamazaki, Atsushi; Kotaki, Hideyuki; Kondo, Shuji; Homma, Takayuki*; Kanazawa, Shuhei; Nakajima, Kazuhisa; Hayashi, Yukio; et al.
Physical Review E, 71(1), p.015403_1 - 015403_4, 2005/01
Times Cited Count：33 Percentile：76.45(Physics, Fluids & Plasmas)no abstracts in English
Kotaki, Hideyuki; Kando, Masaki; Dewa, Hidenori; Kondo, Shuji; Watanabe, Takahiro*; Ueda, Toru*; Kinoshita, Kenichi*; Yoshii, Koji*; Uesaka, Mitsuru*; Nakajima, Kazuhisa
Nuclear Instruments and Methods in Physics Research A, 455(1), p.166 - 171, 2000/11
Times Cited Count：15 Percentile：67.77(Instruments & Instrumentation)no abstracts in English
Uesaka, Mitsuru*; Kotaki, Hideyuki; Nakajima, Kazuhisa; Harano, Hideki*; Kinoshita, Kenichi*; Watanabe, Takahiro*; Ueda, Toru*; Yoshii, Koji*; Kando, Masaki; Dewa, Hidenori; et al.
Nuclear Instruments and Methods in Physics Research A, 455(1), p.90 - 98, 2000/11
Times Cited Count：37 Percentile：88.86(Instruments & Instrumentation)no abstracts in English
Uesaka, Mitsuru*; Kinoshita, Kenichi*; Watanabe, Takahiro*; Sugahara, Jun*; Ueda, Toru*; Yoshii, Koji*; Kobayashi, Tetsuya*; Halz, N.*; Nakajima, Kazuhisa; Sakai, Fumio*; et al.
IEEE Transactions on Plasma Science, 28(4), p.1133 - 1142, 2000/08
Times Cited Count：14 Percentile：41.17(Physics, Fluids & Plasmas)no abstracts in English
Uesaka, Mitsuru*; Watanabe, Takahiro*; Kinoshita, Kenichi*; Sugahara, Jun*; Harano, Hideki*; Ueda, Toru*; Yoshii, Koji*; Nakajima, Kazuhisa; Sakai, Fumio*; Kotaki, Hideyuki; et al.
Nihon Genshiryoku Gakkai-Shi, 42(4), p.310 - 324, 2000/04
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)no abstracts in English
Kotaki, Hideyuki; Kando, Masaki; Dewa, Hidenori; Kondo, Shuji; Watanabe, Takahiro*; Ueda, Toru*; Kinoshita, Kenichi*; Yoshii, Koji*; Uesaka, Mitsuru*; Nakajima, Kazuhisa
Lasers Plasma Generation and Diagnostics (Proceedings of SPIE Vol.3935), p.149 - 155, 2000/01
no abstracts in English
