-
Z Zhang,
H Nishimura,
T Namimoto,
S Fujioka,
Y Arikawa,
M Nishikino,
T Kawachi,
A Sagisaka,
H Hosoda, S Orimo,
K Ogura,
A Pirozhkov,
A Yogo,
Y Okano,
H Kiriyama,
K Kondo,
S Ohshima,
H Azechi
[show abstract]
[hide abstract]
ABSTRACT: X-ray line spectra ranging from 17 to 77 keV were quantitatively measured with a Laue spectrometer, composed of a cylindrically curved crystal and a detector. Either a visible CCD detector coupled with a CsI phosphor screen or an imaging plate can be chosen, depending on the signal intensities and exposure times. The absolute sensitivity of the spectrometer system was calibrated using pre-characterized laser-produced x-ray sources and radioisotopes. The integrated reflectivity for the crystal is in good agreement with predictions by an open code for x-ray diffraction. The energy transfer efficiency from incident laser beams to hot electrons, as the energy transfer agency for specific x-ray line emissions, is derived as a consequence of this work.
The Review of scientific instruments 05/2012; 83(5):053502. · 1.52 Impact Factor
-
A. Yogo,
H. Kiriyama,
M. Mori,
T. Zh. Esirkepov,
K. Ogura,
A. Sagisaka, S. Orimo,
M. Nishiuchi,
A. S. Pirozhkov,
H. Nagatomo, [......],
T. Shimomura,
M. Tanoue,
A. Akutsu,
H. Okada,
T. Motomura,
S. Kondo,
S. Kanazawa,
S. V. Bulanov,
P. R. Bolton,
H. Daido
[show abstract]
[hide abstract]
ABSTRACT: We demonstrate laser-ion acceleration from a near-critical density plasma, using amplified
spontaneous emission (ASE) to convert a solid foil target into a lower-density target. In order
to investigate the target density dependence of the laser-ion acceleration, two cases were investigated for which the ASE
intensity differed by three orders of magnitude. In the low contrast case the beam centre for higher energy protons is shifted
closer to the laser-propagation direction of 45○, while the centre of lower-energy beam remains near the target normal direction. We show that a near-critical density plasma
can be used to control proton beam direction based on its energy.
The European Physical Journal D 04/2012; 55(2):421-425. · 1.48 Impact Factor
-
M. Suzuki,
H. Kiriyama,
I. Daito,
H. Okada,
Y. Nakai, S. Orimo,
M. Sato,
Y. Tamaoki,
T. Yoshii,
J. Maeda,
S. Matsuoka,
H. Kan,
P. R. Bolton,
H. Daido,
S. Kawanishi
[show abstract]
[hide abstract]
ABSTRACT: 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 1030nm femtosecond laser pulses from a broadband Yb oscillator
to over 6.5mJ with a total gain of greater than 107 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.
Applied Physics B 04/2012; 97(2):379-382. · 2.19 Impact Factor
-
M. Nishiuchi,
H. Daido,
A. Sagisaka,
K. Ogura, S. Orimo,
M. Kado,
A. Yogo,
M. Mori,
Y. Hayashi,
S. Bulanov,
A. Fukumi,
Z. Li,
A. Noda,
S. Nakamura
[show abstract]
[hide abstract]
ABSTRACT: A highly collimated sub-MeV proton beam with the divergence angle of 10 degrees is obtained during the interaction of a few
terawatt pulse from a table-top Ti:sapphire laser with a thin metallic foil. This beam is used for proton shadowgraphy. The
quality of the 107 laminar protons per bunch is sufficient for good quality projection imaging of a micrometer size mesh structure, giving a
quantitative characterization of the proton beam, such as the transverse emittance of less than 0.1π mm mrad. These experimental
results open up a new perspective in imaging techniques.
Applied Physics B 04/2012; 87(4):615-621. · 2.19 Impact Factor
-
Z Zhang,
M Nishikino,
H Nishimura,
T Kawachi,
A S Pirozhkov,
A Sagisaka, S Orimo,
K Ogura,
A Yogo,
Y Okano,
S Ohshima,
S Fujioka,
H Kiriyama,
K Kondo,
T Shimomura,
S Kanazawa
[show abstract]
[hide abstract]
ABSTRACT: Kα line emissions from Mo and Ag plates were experimentally studied using clean, ultrahigh-intensity femtosecond laser pulses. The absolute yields of Kα x-rays at 17 keV from Mo and 22 keV from Ag were measured as a function of the laser pulse contrast ratio and irradiation intensity. Significantly enhanced Kα yields were obtained for both Mo and Ag by employing high contrast ratios and irradiances. Conversion efficiencies of 4.28×10⁻⁵/sr for Mo and 4.84×10⁻⁵/sr for Ag, the highest values obtained to date, were demonstrated with contrast ratios in the range 10⁻¹⁰ to 10⁻¹¹.
Optics Express 02/2011; 19(5):4560-5. · 3.59 Impact Factor
-
A. Sagisaka,
H. Daido,
K. Ogura, S. Orimo,
Y. Hayashi,
M. Nishiuchi,
M. Mori,
A. Yogo,
M. Kado,
T. Morita, [......],
Y. Oishi,
T. Nayuki,
T. Fujii,
K. Nemoto,
S. Nakamura,
A. Noda,
S. V. Bulanov,
T. Zh. Esirkepov,
A. S. Pirozhkov,
T. Utsumi
[show abstract]
[hide abstract]
ABSTRACT: Intense laser driven thin foil target acts as a double layered coulomb system that produces collimated ions as well as high-order
harmonics, hard X-ray, and so on. From this point of view, we observed the electron density distribution of preformed plasmas
of a tantalum foil target with two-color probe beams as an interferometer. The preformed plasma at the front side of the target
was generated by a prepulse with a high-intensity Ti:sapphire laser pulse. On the other hand, the preformed plasma at the
rear side was not observed. In our experimental condition, high-energy electrons and protons were observed. The characterization
of preformed plasmas will contribute to describe the high-intensity laser-thin foil interactions.
05/2010: pages 273-277;
-
M. Nishiuchi,
H. Daido,
I. Daito,
M. Ikegami,
M. Mori, S. Orimo,
K. Ogura,
A. Sagisaka,
A. Yogo,
A. S. Pirozhkov, [......],
I. W. Choi,
J. H. Sung,
J. Lee,
Y. Oishi,
T. Fujii,
K. Nemoto,
H. Souda,
A. Noda,
Y. Iseki,
T. Yoshiyuki
[show abstract]
[hide abstract]
ABSTRACT: As a benchmark experiment to realize a novel and compact laser driven proton accelerator whose significant features are high number density in a short pulse width (∼ns), 2.4 MeV laser driven proton beam is stably focused at 1 Hz repetition rate by using a pair of permanent quadrupole magnets (PMQs) with large apertures whose diameters and field strengths are 3.5 cm and 55 T∕m for the first and 2.3 cm and 60 T∕m for the second magnets, respectively. The proton beam has been focused to a focal spot of 3×8 mm2 in horizontal and vertical direction (full width at half maximum) at 650∼mm from the source, which is well reproduced by the simulation. The further optimization of the focusing system will sure to pave a way to the novel proton accelerator with which we can investigate the physics appeared in the short time scale as well as that in a high energy density matter, oncology, astrophysics, and so on.
AIP Conference Proceedings. 07/2009; 1153(1):151-158.
-
I W Choi,
C M Kim,
J H Sung,
T J Yu,
S K Lee,
I J Kim,
Y-Y Jin,
T M Jeong,
N Hafz,
K H Pae, [......],
A Sagisaka,
M Nishiuchi,
I Daito,
Y Oishi,
Y Iwashita,
S Nakamura,
K Nemoto,
A Noda,
H Daido,
J Lee
[show abstract]
[hide abstract]
ABSTRACT: An ion spectrometer, composed of a time-of-flight spectrometer (TOFS) and a Thomson parabola spectrometer (TPS), has been developed to measure energy spectra and to analyze species of laser-driven ions. Two spectrometers can be operated simultaneously, thereby facilitate to compare the independently measured data and to combine advantages of each spectrometer. Real-time and shot-to-shot characterizations have been possible with the TOFS, and species of ions can be analyzed with the TPS. The two spectrometers show very good agreement of maximum proton energy even for a single laser shot. The composite ion spectrometer can provide two complementary spectra measured by TOFS with a large solid angle and TPS with a small one for the same ion source, which are useful to estimate precise total ion number and to investigate fine structure of energy spectrum at high energy depending on the detection position and solid angle. Advantage and comparison to other online measurement system, such as the TPS equipped with microchannel plate, are discussed in terms of overlay of ion species, high-repetition rate operation, detection solid angle, and detector characteristics of imaging plate.
The Review of scientific instruments 06/2009; 80(5):053302. · 1.52 Impact Factor
-
A. Yogo,
K. Sato,
M. Nishikino,
M. Mori,
T. Teshima,
H. Numasaki,
M. Murakami,
Y. Demizu,
S. Akagi,
S. Nagayama, [......],
H. Okada,
S. Kanazawa,
S. Kondo,
T. Shimomura,
Y. Nakai,
M. Tanoue,
H. Sasao,
D. Wakai,
P. R. Bolton,
H. Daido
[show abstract]
[hide abstract]
ABSTRACT: We report the demonstrated irradiation effect of laser-accelerated protons on human cancer cells. In vitro (living) A549 cells are irradiated with quasimonoenergetic proton bunches of 0.8–2.4 MeV with a single bunch duration of 15 ns. Irradiation with the proton dose of 20 Gy results in a distinct formation of γ-H2AX foci as an indicator of DNA double-strand breaks generated in the cancer cells. This is a pioneering result that points to future investigations of the radiobiological effects of laser-driven ion beams. Unique high-current and short-bunch features make laser-driven proton bunches an excitation source for time-resolved determination of radical yields.
Applied Physics Letters 05/2009; 94(18):181502-181502-3. · 3.84 Impact Factor
-
M. Nishiuchi,
I. Daito,
M. Ikegami,
H. Daido,
M. Mori, S. Orimo,
K. Ogura,
A. Sagisaka,
A. Yogo,
A. S. Pirozhkov, [......],
I. W. Choi,
J. H. Sung,
J. Lee,
Y. Oishi,
T. Fujii,
K. Nemoto,
H. Souda,
A. Noda,
Y. Iseki,
T. Yoshiyuki
[show abstract]
[hide abstract]
ABSTRACT: A pair of conventional permanent magnet quadrupoles is used to focus a 2.4 MeV laser-driven proton beam at a 1 Hz repetition rate. The magnetic field strengths are 55 and 60 T/m for the first and second quadrupoles, respectively. The proton beam is focused to a spot with a size of less than ∼3×8 mm <sup>2</sup> at a distance of 650 mm from the source. This result is in good agreement with the Monte Carlo particle trajectory simulation.
Applied Physics Letters 03/2009; · 3.84 Impact Factor
-
A. S. Pirozhkov,
I. W. Choi,
J. H. Sung,
S. K. Lee,
T. J. Yu,
T. M. Jeong,
I. J. Kim,
N. Hafz,
C. M. Kim,
K. H. Pae, [......],
M. Tanoue,
T. Shimomura,
M. Ikegami,
I. Daito,
M. Kando,
T. Kameshima,
P. Bolton,
S. V. Bulanov,
H. Daido,
D. Neely
[show abstract]
[hide abstract]
ABSTRACT: Using three different laser systems, we demonstrate a convenient and simple plasma based diagnostic of the contrast of high-power short-pulse lasers. The technique is based on measuring the specular reflectivity from a solid target. The reflectivity remains high even at relativistic intensities above 10(19) W/cm(2) in the case of a high-contrast prepulse-free laser. On the contrary, the specular reflectivity drops with increasing intensities in the case of systems with insufficient contrast due to beam breakup and increased absorption caused by preplasma.
Applied Physics Letters 01/2009; 94(24). · 3.84 Impact Factor
-
H. Daido,
A. Pirozhkov,
M. Nishiuchi,
A. Yogo, S. Orimo,
K. Ogura,
A. Sagisaka,
I. Daito,
M. Mori,
M. Ikegami, [......],
Y. -C. Noh,
D. -K. Ko,
J. Lee,
Y. Oishi,
K. Nemoto,
T. Nayuki,
T. Fujii,
H. Nagatomo,
K. Nagai,
H. Nishimura
[show abstract]
[hide abstract]
ABSTRACT: The authors describe firstly the lasers for high intensity physics experiments at JAEA including J-KAREN and JLITE-X lasers
which can deliver 00TW and 0TW laser power, respectively. Secondly the authors describe demonstration of flying mirror technique
which will become a new technique to make a coherent tunable x-ray source. Thirdly a femto-second laser driven incoherent
soft x-ray source and its imaging applications for nano-structures are described. The th topic includes femto-second laser driven multiple quantum beam generation and its applications using a laser driven thin
foil target.
12/2008: pages 33-42;
-
[show abstract]
[hide abstract]
ABSTRACT: We observed high-power terahertz (THz) radiation from a metal foil target excited by terawatt laser pulses. The radiated terahertz pulse spectrum obtained by a Martin-Puplett interferometer was distributed from 0.1 to 0.75 THz. We found that radiation power was significantly increased as the excitation laser power increased. A power-law correlation with an exponent of 2 - 4 was estimated using a curve fitting.
Infrared, Millimeter and Terahertz Waves, 2008. IRMMW-THz 2008. 33rd International Conference on; 10/2008
-
A. Sagisaka,
H. Daido,
A.S. Pirozhkov,
Jinglong Ma,
A. Yogo,
K. Ogura, S. Orimo,
M. Mori,
M. Nishiuchi,
T. Kawachi,
S.V. Bulanov,
T.Zh. Esirkepov,
Y. Oishi,
T. Nayuki,
T. Fujii,
K. Nemoto,
H. Nagatomo
[show abstract]
[hide abstract]
ABSTRACT: We observe UV harmonics and protons with a 7.5-mum-thick polyimide target irradiated with a high-intensity Ti:sapphire laser. The laser intensity dependence of UV harmonics and proton signal is measured by varying the distance between the target surface and the best focus of the laser beam. In the case of appropriate condition for proton generation with a maximum energy of ~2.7 MeV, the weak broad spectrum in the UV region is generated. The UV harmonics of up to the fourth order are generated as the target is moved away from the best focus position. In this condition, the maximum energy of protons is reduced to ~1 MeV. The simultaneous generation of the harmonics and protons is observed at the amplified spontaneous emission intensities between ~5 times 10<sup>11</sup> and ~5 times 10<sup>12</sup> W/cm<sup>2</sup>.
IEEE Transactions on Plasma Science 09/2008; · 1.17 Impact Factor
-
M. Mori,
A. Yogo,
H. Kiriyama,
M. Nishiuchi,
K. Ogura, S. Orimo,
Jinglong Ma,
A. Sagisaka,
S. Kanazawa,
S. Kondo, [......],
K. Nemoto,
Il Woo Choi,
Tae Jun Yu,
Do-Kyeong Ko,
Jongmin Lee,
H. Daido,
T. Esirkepov,
S.V. Bulanov,
P.R. Bolton,
T. Kimura
[show abstract]
[hide abstract]
ABSTRACT: A dependence of cutoff proton kinetic energy on laser prepulse duration has been observed. Amplified spontaneous emission pedestal duration is controlled by a fast electrooptic pulse slicer where the rise time is estimated to be 130 ps. We demonstrate a new correlated spectral technique for determining this rise time using a stretched frequency-chirped pulse.
IEEE Transactions on Plasma Science 09/2008; · 1.17 Impact Factor
-
I. W. Choi,
N. Hafz,
T. M. Jeong,
H. T. Kim,
C. M. Kim,
T. J. Yu,
J. H. Sung,
K.‐H. Hong,
S. K. Lee,
Y.‐C. Noh, [......],
A. S. Pirozhkov,
S. V. Bulanov,
M. Nishiuchi,
H. Daido,
Y. Oishi,
K. Nemoto,
S. Nakamura,
Y. Iwashita,
T. Shirai,
A. Noda
[show abstract]
[hide abstract]
ABSTRACT: At the Advanced Photonics Research Institute (APRI) in Korea, we have a Ti:sapphire laser system which delivers laser pulses of 100‐TW peak power and 32‐fs pulse duration at the repetition rate of 10 Hz. This laser facility is being used to develop compact laser‐driven proton and electron sources. Energetic protons are produced by irradiating the laser pulse on a thin foil target made of copper and polyimide via the target normal sheath acceleration. Proton beam with maximum energy of up to 4 MeV was generated from a polyimide target, and showed high energy conversion efficiency from laser to proton energy. Generation of high‐energy electron beams by the laser wakefield acceleration was performed by focusing the laser pulses onto a 4 mm‐long He‐gas jet. Quasi‐monoenergetic electron beam with peak energy of 45 MeV and maximum energy of 130 MeV was produced. The quality and characteristics of electron beams are strongly dependent on the laser‐plasma interaction length which depends on focal length of the focusing optics.
AIP Conference Proceedings. 06/2008; 1024(1):165-172.
-
A Yogo,
H Daido,
S V Bulanov,
T Z Esirkepov,
K Nemoto,
Y Oishi,
T Nayuki,
T Fujii,
K Ogura, S Orimo,
A Sagisaka,
J L Ma,
M Mori,
M Nishiuchi,
A S Pirozhkov,
S Nakamura,
A Noda,
H Nagatomo
[show abstract]
[hide abstract]
ABSTRACT: The duration-controlled amplified spontaneous emission with intensity of 1013W/cm2 is used to convert a 7.5 μm thick polyimide foil into a near-critical plasma, in which the p-polarized, 45 fs, 1019 W/cm2 laser pulse generates 3.8 MeV protons, emitted at some angle between the target normal and the laser propagation direction of 45°. The mechanism which explains the proton generation from the near-critical plasma cloud is discussed using the two-dimensional (2D) particle-in-cell (PIC) simulation.
Journal of Physics Conference Series 06/2008; 112(4):042034.
-
M Nishiuchi,
H Daido,
A Yogo,
A Sagisaka,
K Ogura, S Orimo,
M Mori,
J Ma,
A S Pirozhkov,
H Kiriyama, [......],
S Nakamura,
I W Choi,
T J Yu,
J H Sung,
H T Kim,
T M Jeong,
K -H Hong,
Y -C Noh,
D -K Ko,
J Lee
[show abstract]
[hide abstract]
ABSTRACT: We have performed simultaneous proton and X-ray imaging with an ultra-short and high-intensity Ti: Sap laser system. More than 1010 protons, whose maximum energy reaches 2.5 MeV, were delivered within a ~ps bunch. At the same time, keV X-ray is generated at almost the same place where protons are emitted. We have performed the simultaneous imaging of the copper mesh by using proton and x-ray beams, in practical use of the characteristics of the laser produced plasma that it can provide those beams simultaneously without any serious problems on synchronization.
Journal of Physics Conference Series 06/2008; 112(4):042036.
-
M. Nishiuchi,
H. Daido,
A. Yogo, S. Orimo,
K. Ogura,
J. Ma,
A. Sagisaka,
M. Mori,
A. S. Pirozhkov,
H. Kiriyama, [......],
N. Hafz,
K. H. Pae,
Y.-C. Noh,
D.-K. Ko,
J. Lee,
Y. Oishi,
K. Nemoto,
H. Nagatomo,
K. Nagai,
H. Azuma
[show abstract]
[hide abstract]
ABSTRACT: High-flux energetic protons whose maximum energies are up to 4 MeV are generated by an intense femtosecond titanium:sapphire laser pulse interacting with 7.5, 12.5, and 25 μm thick polyimide tape targets. Laser pulse with an energy of 1.7 J and with a duration of 34 fs is focused with an f/3.4 parabolic mirror giving an intensity of 3×1019 W cm−2. The main pulse to amplified spontaneous emission (ASE) intensity contrast ratio is 2.5×107. The conversion efficiency from the laser energy into the proton kinetic energies is achieved to be ∼ 3%, which is comparable to or even higher than those achieved in the previous works; using nanometer-thick targets, in combination with the short-pulse lasers that have almost the same pulse width and the intensity but different main pulse to ASE intensity contrast of ∼ 1010 [
Neely et al., Appl. Phys. Lett. 89, 021502 (2006)
], in which the authors claim that the main mechanism is target normal sheath acceleration; or using the 7.5 μm thick polyimide target, in combination with the short-pulse laser, which has almost the same pulse width and the intensity, but the main pulse to ASE intensity contrast ratio was controlled to be 2.5×105 [
Yogo et al., Phys. Rev. E 77, 016401 (2008)
], in which the authors claim the efficient acceleration by the mechanism of the underdense plasma model. The contrast ratio of the present experiment is in between these two experiments. The possible mechanism of this regime is discussed.
Physics of Plasmas 05/2008; 15(5):053104-053104-10. · 2.15 Impact Factor
-
A Yogo,
H Daido,
S V Bulanov,
K Nemoto,
Y Oishi,
T Nayuki,
T Fujii,
K Ogura, S Orimo,
A Sagisaka,
J-L Ma,
T Zh Esirkepov,
M Mori,
M Nishiuchi,
A S Pirozhkov,
S Nakamura,
A Noda,
H Nagatomo,
T Kimura,
T Tajima
[show abstract]
[hide abstract]
ABSTRACT: Duration-controlled amplified spontaneous emission with an intensity of 10(13) W/cm(2) is used to convert a 7.5-microm -thick polyimide foil into a near-critical plasma, in which the p -polarized, 45-fs , 10(19) -Wcm (2) laser pulse generates 3.8-MeV protons, emitted at some angle between the target normal and the laser propagation direction of 45 degrees . Particle-in-cell simulations reveal that the efficient proton acceleration is due to the generation of a quasistatic magnetic field on the target rear side with magnetic pressure inducing and sustaining a charge separation electrostatic field.
Physical Review E 02/2008; 77(1 Pt 2):016401. · 2.26 Impact Factor
