Laser-driven multi-charged heavy ion beam acceleration

Nishiuchi, Mamiko; Sakaki, Hironao; Esirkepov, T. Z.; Nishio, Katsuhisa; Pikuz, T. A.*; Faenov, A. Ya.*; Pirozhkov, A. S.; Sagisaka, Akito; Ogura, Koichi; Kanasaki, Masato; et al.

Research Using Extreme Light; Entering New Frontiers with Petawatt-Class Lasers II (Proceedings of SPIE, Vol.9515), p.95151D_1 - 95151D_4, 2015/06

https://doi.org/10.1117/12.2179204

Experimental demonstration of multi-charged heavy ion acceleration from the interaction between the ultra-intense short pulse laser system and the metal target is presented. The laser pulse of 10 J laser energy, 36 fs pulse width, and the contrast level of 10 from 200 TW class Ti:sapphire J-KAREN laser system at JAEA is used in the experiment. Almost fully stripped Fe ions accelerated up to 0.9 GeV are demonstrated. This is achieved by the high intensity laser field of 10Wcm interacting with the solid density target. The demonstrated iron ions with high charge to mass ratio (Q/M) is difficult to be achieved by the conventional heavy ion source technique in the accelerators.

Mie scattering from submicron-sized CO clusters formed in a supersonic expansion of a gas mixture

Jinno, Satoshi; Fukuda, Yuji; Sakaki, Hironao; Yogo, Akifumi; Kanasaki, Masato; Kondo, Kiminori; Faenov, A. Ya.*; Skobelev, I. Yu.*; Pikuz, T.; Boldarev, A. S.*; et al.

Optics Express (Internet), 21(18), p.20656 - 20674, 2013/09

https://doi.org/10.1364/OE.21.020656

A detailed mathematical model is presented for a submicron-sized cluster formation in a binary gas mixture flowing through a three-staged conical nozzle. In order to experimentally confirm this model, the cluster sizes have been evaluated using the Mie scattering method, which is to measure the angular distribution of light scattered from targets. The mean sizes of CO clusters produced in the gas mixtures of CO(30%)/H(70%) and CO(10%)/He(90%) are estimated to be 0.28 0.03 m and 0.260.04 m, respectively. In addition, total gas density profiles measured with an interferometer were found to be agreed with the numerical modeling within a factor of two. The dryness ( ratio) in the targets was found to support the numerical modeling. Thus, our mathematical model of cluster formation was proved to be reliable enough for the binary gas mixture by the experimental results.

Characterization of submicron-sized CO clusters formed with a supersonic expansion of a mixed-gas using a three-staged nozzle

Jinno, Satoshi; Fukuda, Yuji; Sakaki, Hironao; Yogo, Akifumi; Kanasaki, Masato; Kondo, Kiminori; Faenov, A. Ya.*; Skobelev, I. Yu.*; Pikuz, T.; Boldarev, A. S.*; et al.

Applied Physics Letters, 102(16), p.164103_1 - 164103_4, 2013/04

https://doi.org/10.1063/1.4802915

The size of CO clusters, produced in a supersonic expansion of a mixed-gas of CO/He or CO/H through a three-staged conical nozzle designed based on the Boldarev's model, has been evaluated by measuring the angular distribution of light scattered from the clusters. The data are analyzed utilizing the Mie scattering theory, and the sizes of CO clusters are estimated as 0.22 m and 0.25 m for the cases of CO/He and CO/H gas mixtures, respectively. The results confirm that the Boldarev's model is reliable enough for the production of micron-sized clusters.

Observations of surface modifications induced by the multiple pulse irradiation using a soft picosecond X-ray laser beam

Ishino, Masahiko; Faenov, A. Ya.*; Tanaka, Momoko; Tamotsu, Satoshi*; Hasegawa, Noboru; Nishikino, Masaharu; Pikuz, T.; Kaihori, Takeshi*; Kawachi, Tetsuya

Applied Physics A, 110(1), p.179 - 188, 2013/01

https://doi.org/10.1007/s00339-012-7100-6

Relativistic high harmonic generation in gas jet targets

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T.; Kawachi, Tetsuya; Sagisaka, Akito; et al.

AIP Conference Proceedings 1465, p.167 - 171, 2012/07

https://doi.org/10.1063/1.4737557

Soft-X-ray harmonic comb from relativistic electron spikes

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T.; Kawachi, Tetsuya; Sagisaka, Akito; et al.

Physical Review Letters, 108(13), p.135004_1 - 135004_5, 2012/03

https://doi.org/10.1103/PhysRevLett.108.135004

We demonstrate a new high-order harmonic generation mechanism reaching the "water window" spectral region in experiments with multi-terawatt femtosecond lasers irradiating gas jets. A few hundred harmonic orders are resolved, giving J/sr pulses. Harmonics are collectively emitted by an oscillating electron spike formed at the joint of the boundaries of a cavity and bow wave created by a relativistically self-focusing laser in underdense plasma. The spike sharpness and stability are explained by catastrophe theory. The mechanism is corroborated by particle-in-cell simulations.

LiF crystals as high spatial resolution neutron imaging detectors

Matsubayashi, Masahito; Faenov, A. Ya.*; Pikuz, T.*; Fukuda, Yuji; Kato, Yoshiaki*; Yasuda, Ryo; Iikura, Hiroshi; Nojima, Takehiro; Sakai, Takuro

Nuclear Instruments and Methods in Physics Research A, 651(1), p.90 - 94, 2011/09

https://doi.org/10.1016/j.nima.2011.01.072

Neutron imaging by color center formation in LiF crystals was applied to standard samples such as a sensitivity indicator (SI) for neutron radiography. The SI was exposed to 5 mm pinhole collimated thermal neutron beam with a LiF crystal and a neutron imaging plate (NIP) for 120 min in JRR-3 thermal neutron radiography facility. The image in NIP was read out with a readout resolution of 50 m. The image of SI in LiF crystal was read out with pixel size of 1.38 m using a laser confocal microscope. All gaps were clearly observed in the images for both LiF crystal and NIP, but small holes were not recognized for NIP. The experiment showed that LiF crystals had excellent characteristics as neutron imaging detectors such as high sensitivity, high spatial resolution, wide dynamic range and so on. In the paper, detailed characteristics of LiF crystals are compared with those of other neutron imaging detectors: NIP, a combination of fluorescent converter and cooled CCD camera.

Two-temperature warm dense matter produced by ultrashort Extreme Vacuum Ultraviolet-Free Electron Laser (EUV-FEL) pulse

Inogamov, N. A.*; Faenov, A. Ya.*; Zhakhovsky, V. V.*; Pikuz, T. A.*; Skobelev, I. Yu.*; Petrov, Y. V.*; Khokhlov, V. A.*; Shepelev, V. V.*; Anisimov, S. I.*; Fortov, V. E.*; et al.

Contributions to Plasma Physics, 51(5), p.419 - 426, 2011/06

https://doi.org/10.1002/ctpp.201110013

Warm dense matter, arising under the action of ultrashort EUV-FEL pulse onto LiF dielectric crystal, is characterized by high temperature of conduction electrons, with their number density achieving values of the order of atom number density at maximum laser fluences in our experiments. Expansion of matter, heated and pressurized through the electron-ion energy exchange, gives rise to the spallative ablation at small fluences and gaseous outflow from a target in the case of large fluences. Ablation threshold is low in comparison with a longer nanosecond XRL.

Laser ablation of gold; Experiment and atomistic simulation

Starikov, S. V.*; Stegailov, V. V.*; Norman, G. E.*; Fortov, V. E.*; Ishino, Masahiko; Tanaka, Momoko; Hasegawa, Noboru; Nishikino, Masaharu; Oba, Toshiyuki*; Kaihori, Takeshi; et al.

JETP Letters, 93(11), p.642 - 647, 2011/04

https://doi.org/10.1134/S0021364011110129

Spallative ablation of dielectrics by X-ray laser

Inogamov, N. A.*; Zhakhovsky, V. V.*; Faenov, A. Ya.*; Khokhlov, V. A.*; Shepelev, V. V.*; Skobelev, I. Y.*; Kato, Yoshiaki*; Tanaka, Momoko; Pikuz, T. A.*; Kishimoto, Maki; et al.

Applied Physics A, 101(1), p.87 - 96, 2010/10

https://doi.org/10.1007/s00339-010-5764-3