Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ogura, Koichi; Nishiuchi, Mamiko; Pirozhkov, A. S.; Tanimoto, Tsuyoshi*; Sagisaka, Akito*; Esirkepov, T. Z.; Kando, Masaki; Shizuma, Toshiyuki; Hayakawa, Takehito; Kiriyama, Hiromitsu; et al.
Optics Letters, 37(14), p.2868 - 2870, 2012/07
Times Cited Count：83 Percentile：95.79(Optics)Using high contrast (10
:1) and high intensity (10
W/cm
) laser pulse with the duration of 40 fs from OPCPA/Ti:Sapphire laser, a 40 MeV proton bunch is obtained, which is a record for laser pulse with energy less than 10 J. The efficiency for generation of protons with kinetic energy above 15 MeV is 0.1%.
Nishiuchi, Mamiko; Pirozhkov, A. S.; Sakaki, Hironao; Ogura, Koichi; Esirkepov, T. Z.; Tanimoto, Tsuyoshi; Kanasaki, Masato; Yogo, Akifumi; Hori, Toshihiko; Sagisaka, Akito; et al.
Physics of Plasmas, 19(3), p.030706_1 - 030706_4, 2012/03
Times Cited Count：6 Percentile：25.51(Physics, Fluids & Plasmas)A 7 MeV proton beam collimated to 16 mrad containing more than 
particles is experimentally demonstrated by focusing a 2J, 60 fs pulse of a Ti:sapphire laser onto targets of different materials and thicknesses placed in a millimeter scale conical holder. The electric potential induced on the target holder by laser-driven electrons accelerates and dynamically controls a portion of a divergent quasi-thermal proton beam originated from the target, producing a quasi-monoenergetic "pencil" beam.
Nishiuchi, Mamiko; Ogura, Koichi; Pirozhkov, A. S.; Tanimoto, Tsuyoshi; Yogo, Akifumi; Sakaki, Hironao; Hori, Toshihiko; Fukuda, Yuji; Kanasaki, Masato; Sagisaka, Akito; et al.
Proceedings of SPIE Europe Optics + Optoelectronics 2011, Vol.8079, 7 Pages, 2011/04
Times Cited Count：0 Percentile：0.01(Optics)Because of the peculiar characteristics of the laser-driven proton beam, many potential applications are proposed including establishing compact medical accelerator for the cancer therapy. For our final destination to establish the compact laser-driven proton accelerator, the experiments are performed to investigate proton and ion acceleration from thin foil targets, using a high contrast, ultra-short laser pulse from the J-KAREN laser at the Japan Atomic Energy Agency. The P-polarized laser pulse with the parameters of 800 nm, 40 fs, 4J, and with extremely high ASE contrast of 10
is focused onto the thin-foil targets with variable materials and thicknesses ranging from 100 um to sub-um. The achieved peak intensity is 
10
Wcm
. The maximum proton energy is reached to 14 MeV. The number of 
10 MeV protons is enough to carry 2 Gy dose onto the skin of the mouse within 10min with 10 Hz operation. This enables us to carry out in-vivo test instead of in-vitro test.
Kuramitsu, Yasuhiro*; Nakanii, Nobuhiko*; Kondo, Kiminori; Sakawa, Yoichi*; Mori, Yoshitaka*; Miura, Eisuke*; Tsuji, Kazuki*; Kimura, Kazuya*; Fukumochi, Shuji*; Kashihara, Mamoru*; et al.
Physical Review E, 83(2), p.026401_1 - 026401_6, 2011/02
Times Cited Count：16 Percentile：65.44(Physics, Fluids & Plasmas)An energy distribution function of energetic particles in the universe or cosmic rays is well represented by a power-law spectrum, therefore, nonthermal acceleration is essential to understand the origin of cosmic rays. A possible candidate for the origin of cosmic rays is wakefield acceleration at relativistic astrophysical perpendicular shocks. Substituting an intensive laser pulse for the large amplitude light waves, we performed a model experiment of the shock environments in a laboratory plasma.
Kuramitsu, Yasuhiro*; Nakanii, Nobuhiko*; Kondo, Kiminori; Sakawa, Yoichi*; Mori, Yoshitaka*; Miura, Eisuke*; Tsuji, Kazuki*; Kimura, Kazuya*; Fukumochi, Shuji*; Kashihara, Mamoru*; et al.
Physics of Plasmas, 18(1), p.010701_1 - 010701_4, 2011/01
Times Cited Count：19 Percentile：62.10(Physics, Fluids & Plasmas)Substituting an intensive laser pulse for the large amplitude light waves, we performed a model experiment of the shock environments in a laboratory plasma. An intensive laser pulse was propagated in a plasma tube created by imploding a hollow polystyrene cylinder, as the large amplitude light waves propagated in the upstream plasma at an astrophysical shock. Nonthermal electrons were generated, and the energy distribution functions of the electrons have a power-law component with an index of 2.
Tampo, Motonobu; Awano, Shinya*; Bolton, P.; Kondo, Kiminori; Mima, Kunioki*; Mori, Yoshitaka*; Nakamura, Hirotaka*; Nakatsutsumi, Motoaki*; Stephens, R. B.*; Tanaka, Kazuo*; et al.
Physics of Plasmas, 17(7), p.073110_1 - 073110_5, 2010/07
Times Cited Count：12 Percentile：42.17(Physics, Fluids & Plasmas)Nakamura, Hirotaka*; Chrisman, B.*; Tanimoto, Tsuyoshi*; Borghesi, M.*; Kondo, Kiminori; Nakatsutsumi, Motoaki*; Norimatsu, Takayoshi*; Tampo, Motonobu; Tanaka, Kazuo*; Yabuuchi, Toshinori*; et al.
Physical Review Letters, 102(4), p.045009_1 - 045009_4, 2009/01
Times Cited Count：23 Percentile：73.29(Physics, Multidisciplinary)Interactions between a relativistic-intensity laser pulse and a cone-wire target are studied by changing the focusing point of the pulse. The pulse, when focused on the sidewall of the cone, produced superthermal electrons with an energy 10 MeV, whereas less energetic electrons 1 MeV were produced by the pulse when focused on the cone tip. Efficient heating of the wire was indicated by significant neutron signals observed when the pulse was focused on the tip. Particle-in-cell simulation results show reduced heating of the wire due to energetic electrons produced by specularly reflected light at the sidewall.
Nakanii, Nobuhiko*; Kondo, Kiminori; Kuramitsu, Yasuhiro*; Mori, Yoshitaka*; Miura, Eisuke*; Tsuji, Kazuki*; Kimura, Kazuya*; Fukumochi, Shuji*; Kashihara, Mamoru*; Tanimoto, Tsuyoshi*; et al.
Applied Physics Letters, 93(8), p.081501_1 - 081501_3, 2008/08
Times Cited Count：4 Percentile：18.70(Physics, Applied)Energetic electrons were generated by the interaction of a high-intensity laser pulse with a plasma preformed from a hollow plastic cylinder via laser-driven implosion. The spectra of a comparatively high-density plasma had a bump around 10 MeV. Simple numerical calculations explained the spectra obtained in this experiment. This indicates that the plasma tube has sufficient potential to convert a Maxwellian spectrum to a comparatively narrow spectrum.
Abe, Hiroshi; ; ; ; ; ; Kaneta, Takayoshi*; ; Suzuki, Hiromitsu; Tani, Norio; et al.
JAERI-Research 97-068, 51 Pages, 1997/10
JAERI-Research-97-068.pdf:1.78MB
no abstracts in English
Nishiuchi, Mamiko; Pirozhkov, A. S.; Sakaki, Hironao; Ogura, Koichi; Esirkepov, T. Z.; Tanimoto, Tsuyoshi; Yogo, Akifumi; Hori, Toshihiko; Sagisaka, Akito; Fukuda, Yuji; et al.
no journal, ,
We have successfully accelerate quasi-mono-energetic collimated 7MeV proton beam bt the interaction between the 2J 60fs Ti Sappire laser pulses with the thin-foil target on the target holder with conical cavity. The focusing and energy selection is by the E-field induced along the surface of the conical cavity by the point charge brought away by the escape electrons.
Tanimoto, Tsuyoshi; Ogura, Koichi; Nishiuchi, Mamiko; Pirozhkov, A. S.; Kondo, Kiminori
no journal, ,
no abstracts in English
Ogura, Koichi; Nishiuchi, Mamiko; Pirozhkov, A. S.; Tanimoto, Tsuyoshi; Sagisaka, Akito; Esirkepov, T. Z.; Shizuma, Toshiyuki; Hayakawa, Takehito; Hajima, Ryoichi; Kando, Masaki; et al.
no journal, ,
We demonstrated the energetic proton generation using 40 fsec intense Ti:Sapphire laser pulses. By drastically increasing the interaction intensity approximately 1E21 W/cm with keeping a ultra high contrast of 1E10:1, even without using plasma mirror, over 40 MeV protons were detected with 800 nm thick Al foil.
Nishiuchi, Mamiko; Pirozhkov, A. S.; Ogura, Koichi; Tanimoto, Tsuyoshi*; Sakaki, Hironao; Esirkepov, T. Z.; Yogo, Akifumi; Fukuda, Yuji; Kanasaki, Masato; Sagisaka, Akito; et al.
no journal, ,
Since the first observation of the energetic ion beam from the interaction between the Ultra-high intensity short pulse and solid density target, many experimental efforts have been extensively made in all over the world in order to extend the maximum energy of ions. In the past decade, the highest ion energy recorded is 67.5 MeV for the ps laser pulse from the building size single shot operation system and 25 MeV for the compact Ti:Sapphire laser system which can deliver repetitive sub-ps laser pulses. Here in this paper we present the extension of the maximum energy of protons from the interaction between the short-pulse compact laser system and soild thin-foil target. The laser parameters are 800 nm in wavelength, 40 fs of pulse width, 8 J of energy, 10 contrast and 3
m 
4m (FWHM) of focal spot. The achieved peak intensity is increased up to 10Wcm, which is also well confirmed by the measured electron temperature of 16 MeV.
Ogura, Koichi; Nishiuchi, Mamiko; Pirozhkov, A. S.; Tanimoto, Tsuyoshi; Esirkepov, T. Z.; Sagisaka, Akito; Kando, Masaki; Shizuma, Toshiyuki; Hayakawa, Takehito; Kiriyama, Hiromitsu; et al.
no journal, ,
Without plasma mirror, the maximum proton energy of 40 MeV is obtained using a compact, high spatiotemporal-quality, high-intensity Ti:sapphire laser system with an intensity of 1E21 W/cm/cm for the first time to our knowledge.
W/cm intensity and 10 contrastPirozhkov, A. S.; Ogura, Koichi; Nishiuchi, Mamiko; Esirkepov, T. Z.; Tanimoto, Tsuyoshi*; Shimomura, Takuya; Kiriyama, Hiromitsu; Bulanov, S. V.; Kondo, Kiminori
no journal, ,
We present results of the recent experiments conducted with the J-KAREN laser at KPSI, JAEA. The laser has been carefully tuned and the solid targets aligned to provide on-target irradiance of 10 W/cm (8 J, 40 fs, 200 TW, 3 um spot). The nanosecond contrast was 
and the picosecond contrast has been improved by spectral phase control using high-dynamic range TG-FROG device and Dazzler. Under such conditions, we have observed integer-order and half-integer harmonics in the specular direction, which represents interest for the plasma and preplasma diagnostics relevant to the ion acceleration experiments.
Pirozhkov, A. S.; Ogura, Koichi; Nishiuchi, Mamiko; Esirkepov, T. Z.; Tanimoto, Tsuyoshi*; Shimomura, Takuya; Kiriyama, Hiromitsu; Bulanov, S. V.; Kondo, Kiminori
no journal, ,
We have demonstrated proton acceleration up to 40 MeV from um thick metal foils irradiated by 7.5 J, 200 TW laser pulses of the J-KAREN laser at KPSI, JAEA at the on-target intensity of 10W/cm
. This intensity level is also consistent with the measured electron temperature ranged from 10 to 16 eV. 40 MeV is a new record for the maximum energy of protons accelerated with relatively small-scale (less than 10 J) lasers.
Nishiuchi, Mamiko; Ogura, Koichi; Pirozhkov, A. S.; Tanimoto, Tsuyoshi*; Sagisaka, Akito*; Esirkepov, T. Z.; Kando, Masaki; Kiriyama, Hiromitsu; Shimomura, Takuya; Kondo, Shuji; et al.
no journal, ,
We present the extension of the maximum energy of protons from the interaction between the short-pulse compact laser system and soild thin-foil target. The laser pulses with parameters of 800 nm in wavelength, 40 fs of pulse width, 7 J of energy, 10 contrast are focused onto the target with the peak intensity of more than 10 Wcm, which is also well confirmed by the measured electron temperature of 16 MeV. The Al-0.8m-thick or SUS-2.5m-thick targets are irradiated from 45 degrees incidence angle. The observation of the proton beam is conducted with CR-39 stack detector set at the rear side of the target 55 mm downstream. The direction of the higher energy protons are deflected away from the target normal direction for Al-0.8m-thick target. The most probable explanation of this is due to the deformation of the target shape caused by the ASE pedestal pulse component.
Nishiuchi, Mamiko; Ogura, Koichi; Tanimoto, Tsuyoshi*; Pirozhkov, A. S.; Sakaki, Hironao; Fukuda, Yuji; Kanasaki, Masato; Kando, Masaki; Esirkepov, T. Z.; Sagisaka, Akito*; et al.
no journal, ,
We present the extension of the maximum energy of protons from the interaction between the short-pulse compact laser system and solid thin-foil target. The laser pulses with parameters of 800 nm in wavelength, 40 fs of pulse width, 7 J of energy, 10 contrast are focused onto the target with the peak intensity of more than 10 Wcm, which is also well confirmed by the measured electron temperature of 16 MeV. We report about the acceleration mechanism as well as future prospect on the proton acceleration experiment at JAEA.
Tanimoto, Tsuyoshi; Sakaki, Hironao; Nishiuchi, Mamiko; Fukuda, Yuji; Hori, Toshihiko; Nishio, Katsuhisa; Kondo, Kiminori
no journal, ,
no abstracts in English
Kanasaki, Masato; Yamauchi, Tomoya*; Nishiuchi, Mamiko; Pirozhkov, A. S.; Sakaki, Hironao; Ogura, Koichi; Tanimoto, Tsuyoshi; Yogo, Akifumi; Hori, Toshihiko*; Sagisaka, Akito; et al.
no journal, ,
A precise energy measurement for the laser-driven proton beam has been performed by utilizing stacked CR-39 covered with 13-m thick aluminum filter. The proton beam was generated by exposing a thin foil target to an intense femtosecond laser pulse from the J-KAREN laser system. By analyzing the etch pit growth curves with multi-step etching technique. It, it is found that the maximum energy of the proton beam was evaluated ten times more precise than that by using the conventional time-of-flight (TOF) method.
