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

https://doi.org/10.1063/1.3204528

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.

Generation of above 10 temporal contrast, above 10W/cm peak intensity pulses at a 10 Hz repetition rate using an OPCPA preamplifier in a double CPA, Ti:sapphire laser system

Kiriyama, Hiromitsu; Mori, Michiaki; Nakai, Yoshiki; Shimomura, Takuya; Tanoue, Manabu*; Okada, Hajime; Kondo, Shuji; Kanazawa, Shuhei; Sagisaka, Akito; Daito, Izuru; et al.

AIP Conference Proceedings 1153, p.3 - 6, 2009/07

https://doi.org/10.1063/1.3204551

We demonstrate a high-contrast, high-intensity double chirped-pulse amplification (CPA) Ti:sapphire laser system using an optical parametric chirped-pulse amplifier (OPCPA) as a preamplifier. By injecting cleaned microjoule seed pulses into the OPCPA, a temporal contrast greater than 10 within picosecond times before the main femtosecond pulse is demonstrated with the output pulse energy of 1.7 J and pulse duration of 30 fs, corresponding to a peak power of 60 TW at a 10 Hz repetition rate. This system uses a cryogenically-cooled Ti:sapphire final amplifier and generates focused peak intensities in excess of 10 W/cm.

Ion acceleration in the interaction of short pulse laser radiation with the cluster-gas target

Fukuda, Yuji; Faenov, A. Y.; Tampo, Motonobu; Pikuz, T. A.*; Nakamura, Tatsufumi; Kando, Masaki; Hayashi, Yukio; Yogo, Akifumi; Sakaki, Hironao; Kameshima, Takashi; et al.

AIP Conference Proceedings 1153, p.85 - 93, 2009/07

https://doi.org/10.1063/1.3204561

When the target consists of solid-density clusters embedded in the background gas, its irradiation by high intensity laser light renders ion acceleration a truly unique property. We present that the cluster-gas target, which consists of submicron-sized clusters and background gases, irradiated by a few TW laser pulse produces high energy ions upward of the order of 10-20 MeV/n in the forward direction.

Effects of the laser pulse irradiation point on a double layer target on the accelerated ion beam parameters

Morita, Toshimasa; Bulanov, S. V.; Esirkepov, T. Z.; Koga, J. K.; Yamagiwa, Mitsuru

AIP Conference Proceedings 1153, p.103 - 112, 2009/07

https://doi.org/10.1063/1.3204513

In proton acceleration by a laser pulse obliquely incident on a double layer target, it is shown by PIC simulations that the energy spread of the generated protons can be reduced by irradiating the laser pulse on to the off-center position of the target. This provides a way to control the proton energy spectrum. The high energy protons are found to come from an area shifted from the initial target center towards the propagation direction of the laser pulse. We show that the high energy protons with much smaller energy spread can be obtained by appropriately adjusting the size and position of the second proton layer.

Pulse compression of Nd:YAG laser with stimulated Brillouin scattering for Compton backscattered X-ray source

Kawase, Keigo; Shimomura, Takuya; Kando, Masaki; Yoshida, Hidetsugu*; Bulanov, S. V.

no journal, , 

Observation of low frequency electromagnetic radiation from laser-plasmas

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

no journal, , 

As a result of laser-plasma interaction, an intense laser pulse can make a cavity in underdense plasma, which contains some of the energy of the laser pulse. This structure is called relativistic soliton. Solitons are predicted to store relativistic intensity of downshifted electromagnetic (EM) waves and finally emit radiation. Although a structure of solitons were observed in an experiment using proton beam imaging, however, no downshifted EM wave generation were reported, at least, recognized due to the result of soliton formation. We have tried to measure such downshifted EM radiation and observed signals which have same polarization as the pump laser at the wavelength of 5 m. Due to the same polarization, we attribute this radiation to the emission from solitons.