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Journal Articles

Development of a sub-MeV X-ray source via Compton backscattering

Kawase, Keigo; Kando, Masaki; Hayakawa, Takehito; Daito, Izuru; Kondo, Shuji; Homma, Takayuki; Kameshima, Takashi*; Kotaki, Hideyuki; Chen, L. M.*; Fukuda, Yuji; et al.

Nuclear Instruments and Methods in Physics Research A, 637(1, Suppl.), p.S141 - S144, 2011/05

 Times Cited Count:7 Percentile:49.05(Instruments & Instrumentation)

We report the present status of the sub-MeV X-ray generation via Compton backscattering by using 150-MeV electron beam and the Nd:YAG laser. In particular, we show the result of the X-ray generation experiment and of the laser pulse compression for increasing the X-ray flux.

Journal Articles

Manipulation and electron-oscillation-measurement of laser accelerated electron beams

Kotaki, Hideyuki; Hayashi, Yukio; Kawase, Keigo; Mori, Michiaki; Kando, Masaki; Homma, Takayuki; Koga, J. K.; Daido, Hiroyuki; Bulanov, S. V.

Plasma Physics and Controlled Fusion, 53(1), p.014009_1 - 014009_7, 2011/01

 Times Cited Count:5 Percentile:23.46(Physics, Fluids & Plasmas)

Journal Articles

Intense and reproducible K$$_{alpha}$$ emissions from micron-sized Kr cluster target irradiated with intense femtosecond laser pulses

Hayashi, Yukio; Fukuda, Yuji; Faenov, A. Y.*; Kando, Masaki; Kawase, Keigo; Pikuz, T. A.*; Homma, Takayuki; Daido, Hiroyuki; Bulanov, S. V.

Japanese Journal of Applied Physics, 49(12), p.126401_1 - 126401_3, 2010/12

 Times Cited Count:12 Percentile:45.91(Physics, Applied)

Journal Articles

Control of the laser accelerated electron beam

Kotaki, Hideyuki; Hayashi, Yukio; Kawase, Keigo; Mori, Michiaki; Kando, Masaki; Homma, Takayuki; Bulanov, S. V.

JAEA-Conf 2010-002, p.99 - 102, 2010/06

Journal Articles

Improvement of SBS laser pulse compression system for the Compton backscattered X-ray source

Kawase, Keigo; Kando, Masaki; Hayakawa, Takehito; Daito, Izuru; Kondo, Shuji; Homma, Takayuki; Kameshima, Takashi*; Kotaki, Hideyuki; Chen, L. M.*; Fukuda, Yuji; et al.

JAEA-Conf 2010-002, p.95 - 98, 2010/06

At the previous symposium in Advanced Photon Research, we proposed and demonstrated the laser pulse compression via stimulated Brillouin scattering (SBS) for increasing the flux of the Compton backscattered X rays. After that, we improved the SBS pulse compression system by introducing the image relay in the laser transport line. As a result, we achieve the stably compressed laser pulse with a duration of 2.1 ns and with an energy of 0.84 J. By installing this system into the Compton backscattered X-ray source, the X-ray flux will be increased 3.2 times for the present system at the KPSI-JAEA.

Journal Articles

Metrology of wide field of view nano-thickness foils' homogeneity by conventional and phase contrast soft X-ray imaging

Faenov, A. Y.; Pikuz, T.*; Fukuda, Yuji; Kando, Masaki; Kotaki, Hideyuki; Homma, Takayuki; Kawase, Keigo; Skobelev, I.*; Gasilov, S.*; Kawachi, Tetsuya; et al.

Japanese Journal of Applied Physics, 49(6), p.06GK03_1 - 06GK03_5, 2010/06

 Times Cited Count:8 Percentile:34.47(Physics, Applied)

Journal Articles

Control and pulsewidth-measurement of laser accelerated electron beams

Kotaki, Hideyuki; Hayashi, Yukio; Kawase, Keigo; Mori, Michiaki; Kando, Masaki; Homma, Takayuki; Koga, J. K.; Bulanov, S. V.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3608 - 3610, 2010/05

Journal Articles

Measurement of the parametric X-rays with the rocking curve method

Hayashi, Yukio; Kando, Masaki; Kotaki, Hideyuki; Kawase, Keigo; Homma, Takayuki; Bulanov, S. V.

Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.208 - 210, 2010/05

Parametric X-ray generation is one of the ways to obtain a monochromatic X-ray. The X-ray is generated through the interaction between high energy electrons and a crystal. The relationship between an X-ray wavelength and an angle of emission is followed by the Bragg condition. Therefore the monochromatic energy of the X-ray can be varied continuously by rotating the crystal. This tunability of X-ray wavelength is suitable for various applications. Here, we have measured 10 keV parametric X-rays with applying a rocking curve method. In this scheme, a large number of parametric X-rays are detected simultaneously. This enables us to find and tune the parametric X-ray quickly. As a result, we could find the sharp peak from this method with the Microtron accelerator at JAEA and a Si crystal. Since the peak angle is consistent to the Bragg condition for the 10 keV parametric X-ray generation, we think 10 keV photons have been generated through the parametric X-ray mechanism.

Journal Articles

Method of observing the spot where full-power counter-propagating laser pulses collide in plasma media

Kawase, Keigo; Kando, Masaki; Pirozhkov, A. S.; Homma, Takayuki; Kameshima, Takashi*; Daito, Izuru; Hayashi, Yukio; Kotaki, Hideyuki; Fukuda, Yuji; Esirkepov, T. Z.; et al.

Applied Physics Express, 3, p.016101_1 - 016101_3, 2010/01

 Times Cited Count:2 Percentile:10.44(Physics, Applied)

A new observation method of providing a precise collision of two full-power counter-propagating laser pulses is proposed and demonstrated. The method is a combination of top-view imaging, side-view shadowgram, extra-ultraviolet (XUV) spectrograph, and returning pulse monitoring. This allows us to align two counter-propagating laser pulses at their colliding point in a real situation (full power laser operation in plasma). The achieved spatial resolution of the monitor in the plasma is 1.35 $$mu{rm m}$$ with the precision level of alignment better than 15 $$mu{rm m}$$ even when there is plasma present.

Journal Articles

Electron optical injection with head-on and countercrossing colliding laser pulses

Kotaki, Hideyuki; Daito, Izuru; Kando, Masaki; Hayashi, Yukio; Kawase, Keigo; Kameshima, Takashi*; Fukuda, Yuji; Homma, Takayuki; Ma, J.*; Chen, L. M.*; et al.

Physical Review Letters, 103(19), p.194803_1 - 194803_4, 2009/11

 Times Cited Count:55 Percentile:88.11(Physics, Multidisciplinary)

Journal Articles

Submicron ionography of nanostructures using a femtosecond- laser-driven-cluster-based source

Faenov, A. Y.; Pikuz, T. A.*; Fukuda, Yuji; Kando, Masaki; Kotaki, Hideyuki; Homma, Takayuki; Kawase, Keigo; Kameshima, Takashi*; Pirozhkov, A. S.; Yogo, Akifumi; et al.

Applied Physics Letters, 95(10), p.101107_1 - 101107_3, 2009/09

 Times Cited Count:30 Percentile:76.03(Physics, Applied)

Journal Articles

Generation of parametric X-rays by using electron accelerator

Hayashi, Yukio; Kando, Masaki; Kotaki, Hideyuki; Kawase, Keigo; Homma, Takayuki; Bulanov, S. V.

AIP Conference Proceedings 1153, p.223 - 229, 2009/07

We generate monochromatic X rays (10 keV) in a method called parametric X-ray emission. When relativistic electrons are injected into a crystal plane, monochromatic X rays are radiated toward the reflected direction of the crystal plane. A 150 MeV electron beam and a thin Si (111) crystal were used for this experiment. We measured the rocking curve of the crystal and found a clear peak around the Bragg angle. We conclude that this peak is due to the parametric X-ray radiation. In future, we will try parametric X-ray generation by using laser-plasma electrons, which is one of the useful applications for laser-plasma electrons.

Journal Articles

Contrast effect on the laser injected electron beam

Kotaki, Hideyuki; Kando, Masaki; Daito, Izuru; Homma, Takayuki; Kameshima, Takashi; Kawase, Keigo; Chen, L.-M.*; Fukuda, Yuji; Kiriyama, Hiromitsu; Kondo, Shuji; et al.

AIP Conference Proceedings 1153, p.176 - 181, 2009/07

Journal Articles

Demonstration of flying mirror with improved efficiency

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Fukuda, Yuji; Chen, L.-M.*; Daito, Izuru; Ogura, Koichi; Homma, Takayuki; Hayashi, Yukio; Kotaki, Hideyuki; et al.

AIP Conference Proceedings 1153, p.274 - 284, 2009/07

Journal Articles

MeV- and sub-MeV-photon sources based on Compton backscattering at SPring-8 and KPSI-JAEA

Kawase, Keigo; Kando, Masaki; Hayakawa, Takehito; Daito, Izuru; Kondo, Shuji; Homma, Takayuki; Kameshima, Takashi; Kotaki, Hideyuki; Chen, L.*; Fukuda, Yuji; et al.

Nuclear Physics Review, 26(Suppl.), p.94 - 99, 2009/07

We constructed MeV- and sub-MeV-photon sources by means of Compton backscattering with a laser light and an electron beam at SPring-8 and KPSI-JAEA. MeV-photon source consists of a continuous-wave optically-pumped far infrared laser and an 8-GeV stored electron beam. Sub-MeV-photon source consists of a Nd:YAG pulse-laser and an 150-MeV electron beam accelerated by a microtron. Both source have been succeeded backscattered photon generation. In this talk, I will present characteristics and future prospects of these photon sources.

Journal Articles

Improvement of the quality and stability of electron bunch using countercrossing laser beam

Kotaki, Hideyuki; Daito, Izuru; Kando, Masaki; Hayashi, Yukio; Ma, J.-L.; Chen, L.-M.; Esirkepov, T. Z.; Fukuda, Yuji; Homma, Takayuki; Pirozhkov, A. S.; et al.

IEEE Transactions on Plasma Science, 36(4), p.1760 - 1764, 2008/08

 Times Cited Count:8 Percentile:32.07(Physics, Fluids & Plasmas)

The counter-crossing injection, which is a realistic setup for applications, by two sub-relativistic laser pulses colliding is demonstrated in sub-relativistic intensity laser pulse interaction with plasma. The laser pulses in plasma are self-focused to higher intensity when the laser power is above the threshold of a relativistic self-focusing. The collision of self-focused laser pulses generates a high-quality electron beam with high repeatability. The generated monoenergetic electron beam has 14 MeV of the peak energy, 11% of the energy spread, 22 pC of the charge, 1.6$$pi$$mm mrad of the normalized emittance, and 50% of the repeatability.

Journal Articles

"J-KAREN"; High intensity laser

Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya*; Tanoue, Manabu*; Akutsu, Atsushi; Okada, Hajime; Motomura, Tomohiro*; Kondo, Shuji; Kanazawa, Shuhei; et al.

JAEA-Conf 2008-007, p.13 - 16, 2008/08

One of the main bottlenecks for the applications of ultrashort and ultrahigh-peak power lasers in high-field physics is a temporal contrast of the pulses. In ultrahigh-peak power lasers, a nanosecond background of the amplified spontaneous emission (ASE) is generated at the same time as the femtosecond pulse. This background is mostly generated in the preamplifier (regenerative, multipass amplifier). Even though the contrast level is usually in the range from 10$$^{-5}$$ to 10$$^{-6}$$, this level is not sufficiently low at relativistic intensities greater than 10$$^{18} $$W/cm$$^{2}$$ to avoid unwanted pre-plasmas generation. We demonstrated a high-contrast, high-peak power laser with optical parametric chirped-pulse amplification (OPCPA). With the use of OPCPA, contrast is enhanced to better than 7$$times$$10$$^{-9}$$ in a few picoseconds before the main pulse, which corresponds to an improvement of three to four orders in magnitude compared with conventional systems.

Journal Articles

Sub-MeV tunably polarized X-ray production with laser Thomson backscattering

Kawase, Keigo; Kando, Masaki; Hayakawa, Takehito; Daito, Izuru; Kondo, Shuji; Homma, Takayuki; Kameshima, Takashi; Kotaki, Hideyuki; Chen, L.-M.; Fukuda, Yuji; et al.

Review of Scientific Instruments, 79(5), p.053302_1 - 053302_8, 2008/05

 Times Cited Count:19 Percentile:62.52(Instruments & Instrumentation)

Reported in this article is the generation of unique polarized X-rays in the sub-MeV region by means of the Thomson backscattering of the Nd:YAG laser photon with a wavelength of 1064 nm on the 150 MeV electron from the microtron accelerator. The maximum energy of the X-ray photons is estimated to about 400 keV. The total energy of the backscattered X-ray pulse is measured with an imaging plate and a LYSO scintillator. The angular divergence of the X-rays is also measured by using the imaging plate. We confirm that the X-ray beam is polarized according to the laser polarization direction with the Compton scattering method. In addition, we demonstrate the imaging of the object shielded by lead with the generated X-rays.

Journal Articles

Soft X-ray source for nanostructure imaging using femtosecond-laser-irradiated clusters

Fukuda, Yuji; Faenov, A. Y.; Pikuz, T. A.*; Kando, Masaki; Kotaki, Hideyuki; Daito, Izuru; Ma, J.-L.; Chen, L. M.; Homma, Takayuki; Kawase, Keigo; et al.

Applied Physics Letters, 92(12), p.121110_1 - 121110_3, 2008/03

 Times Cited Count:56 Percentile:86.37(Physics, Applied)

The novel soft X-ray light source using the supersonic expansion of the mixed gas of He and CO$$_2$$, when irradiated by a femtosecond Ti:sapphire laser pulse, is observed to enhance the radiation of soft X-rays from the CO$$_2$$ clusters. Using this soft X-ray emissions, nanostructure images of 100-nm thick Mo foils in a wide field of view (mm$$^2$$ scale) with high spatial resolution (800 nm) are obtained with high dynamic range LiF crystal detectors. The local inhomogeneities of soft X-ray absorption by the nanometer-thick foils is measured with an accuracy of less than $$pm$$ 3 %.

Journal Articles

Counter-crossing injection for stable high-quality electron beam generation via laser-plasma interaction

Kotaki, Hideyuki; Daito, Izuru; Hayashi, Yukio; Ma, J.-L.; Chen, L.-M.; Kando, Masaki; Esirkepov, T. Z.; Fukuda, Yuji; Homma, Takayuki; Pirozhkov, A. S.; et al.

Journal of Physics; Conference Series, 112(4), p.042031_1 - 042031_4, 2008/00

 Times Cited Count:1 Percentile:55.27

Laser-driven plasma accelerators have been conceived to be the next-generation particle accelerators, promising ultrahigh field particle acceleration with a very short duration electron beam. In the case of electron beam generation by using one laser pulse via wavebreaking, however, it is not stable. In order to generate a stable high-quality electron beam, optical injection by collision of two laser pulses is proposed. Recently, the electron generation with this approach was demonstrated. The experiment was carried out by the perfect head-on collision, which has problems to the backward laser light and the extraction of the generated electron beam. The counter-crossing injection, which is a realistic setup for applications, by two sub-relativistic laser pulses collision with the colliding angle of 45$$^{circ}$$ is demonstrated. The collision of two laser pulses generates a high-quality electron beam with high repeatability. The generated monoenergetic electron beam has 14.4 MeV of the peak energy, 10.6% of the energy spread, 21.8 pC of the charge, 1.6 $$pi$$ mm mrad of the normalized emittance, and 47.4% of the repeatability.

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