X-ray spectroscopy diagnoses of clusters surviving under prepulses of ultra-intense femtosecond laser pulse irradiation

Faenov, A. Ya.*; Skobelev, I. Yu.*; Pikuz, T.; Pikuz, S. A.*; Fortov, V. E.*; Fukuda, Yuji; Hayashi, Yukio; Pirozhkov, A. S.; Kotaki, Hideyuki; Shimomura, Takuya; et al.

Laser and Particle Beams, 30(3), p.481 - 488, 2012/09

https://doi.org/10.1017/S0263034612000419

Observation and modeling of high resolution spectral features of the inner-shell X-ray emission produced by 10 contrast femtosecond-pulse laser irradiation of argon clusters

Colgan, J.*; Abdallah, J. Jr.*; Faenov, A. Ya.*; Pikuz, T. A.*; Skobelev, I. Yu.*; Fukuda, Yuji; Hayashi, Yukio; Pirozhkov, A. S.; Kawase, Keigo*; Shimomura, Takuya; et al.

High Energy Density Physics, 7(2), p.77 - 83, 2011/06

https://doi.org/10.1016/j.hedp.2011.01.004

A study is made of the ultra-short laser pulse irradiation of Ar cluster targets. Experiments have been performed with large cluster sizes and using very high laser contrasts, which have allowed clear and unambiguous observation of exotic inner-shell transitions in near-neutral Ar ions. The interaction of the main laser pulse with the unperturbed target is a necessary requirement for observing these lines. Our measurements are supported by kinetics calculations in which a very detailed atomic model is used. The calculations predict all of the spectral features found experimentally, and support the notion that the X-ray emission arises from many ion stages of the Ar plasma, from near-neutral through He-like ions, and from a range of plasma temperatures and densities.

Cu NMR study in a heavy-electron system, CaCuRuO

Kato, Harukazu*; Tsuruta, Takuya*; Nishioka, Takashi*; Matsumura, Masahiro*; Sakai, Hironori; Kambe, Shinsaku

Journal of Magnetism and Magnetic Materials, 310(2, Part1), p.251 - 253, 2007/03

Cu NMR measurements have been carried out for CaCuRuO, which shows a heavy-fermion-like behavior although it posseses no f electron moment. The field-sweep spectrum observed can be understood as a powder pattern of a Cu nucleus affected by the quadrupole interaction with no axial symmetry. The quadrupole parameters and the Knight shift of Cu are evaluated.

High-order harmonics from gas jet targets with multi-TW lasers at intensities 10 W/cm

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Faenov, A. Ya.*; Pikuz, T.; Hayashi, Yukio; Kotaki, Hideyuki; Ragozin, E. N.*; Koga, J. K.; Kiriyama, Hiromitsu; et al.

no journal, , 

We discovered a new high-order harmonic generation regime in the interaction of multi-TW relativistic-irradiance femtosecond lasers with gas jet targets. The spectra consisting of hundreds of even and odd harmonic orders are generated by either linearly or circularly polarized pulses. We proposed a new harmonic generation mechanism, where the harmonics are collectively emitted by oscillating electron spikes, whose sharpness and stability are explained by catastrophe theory.

Performance tests of a mask fitting tester for use in nuclear facilities

Nakagawa, Masahiro; Kato, Takuya; Nojima, Shun; Sakai, Toshiya; Shishido, Nobuhito; Umehara, Takashi

no journal, , 

Mask fitting tester "MT-03" is widespread as educational equipment in medical institution and industrial organization. However, there are few examples introduced in order to check the protection performance of purifying respirators in nuclear facilities. In this study, we compared protection factors obtained by MT-03 and those obtained by Mask-man test apparatus "MT-100N". As a result, although the change of measurement result is larger and measured value is higher than that of MT-100N, it was found that protection performance can be checked appropriately.

High-order harmonic comb from relativistic electron spikes

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Pikuz, T.; Faenov, A. Ya.*; Ogura, Koichi; Hayashi, Yukio; Kotaki, Hideyuki; Ragozin, E. N.*; Neely, D.*; et al.

no journal, , 

High-order harmonics from relativistic electron spikes

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Pikuz, T.; Faenov, A. Ya.*; Ogura, Koichi; Hayashi, Yukio; Kotaki, Hideyuki; Ragozin, E. N.*; Neely, D.*; et al.

no journal, , 

Shield effect of the respirator and estimated dose to the lens of the eye for the worker in the cell

Torii, Yosuke; Yamasoto, Kotaro; Kato, Takuya; Yoshitomi, Hiroshi

no journal, , 

no abstracts in English

High-order harmonic generation in gas jet targets by relativistic irradiance lasers

Pirozhkov, A. S.; Kando, Masaki; Esirkepov, T. Z.; Gallegos, P.*; Ahmed, H.*; Ragozin, E. N.*; Faenov, A. Ya.*; Pikuz, T.; Hayashi, Yukio; Kotaki, Hideyuki; et al.

no journal, , 

We have recently discovered a new high-order harmonic generation mechanism based on relativistic-irradiance ( W/cm) femtosecond lasers interacting with gas jet targets. The comb-like spectra consisting of even and odd orders are generated in the forward direction by either linearly or circularly polarized pulses. In experiments with the 9 TW J-KAREN laser, the spectra extended up to the photon energy of 360 eV, within the "water window" spectral range. We demonstrated the photon number scalability with laser power, reaching photons/sr within the 1200.5 nm spectral region at 120 TW with Astra Gemini laser. In this paper we describe the results concerning angular distribution, new data obtained with J-KAREN laser, and the generation mechanism in more details.

High-resolution X-ray spectroscopy diagnostics of early heating stage of clusters by high contrast femtosecond laser pulse

Faenov, A.*; Pikuz, T.; Skobelev, I.*; Fortov, V.*; Colgan, J.*; Abdallah, J. Jr.*; Fukuda, Yuji; Hayashi, Yukio; Pirozhkov, A. S.; Kawase, Keigo*; et al.

no journal, ,