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Miyabe, Masabumi; Satou, Yukihiko; Wakaida, Ikuo; Terabayashi, Ryohei*; Sonnenschein, V.*; Tomita, Hideki*; Zhao, Y.*; Sakamoto, Tetsuo*
Journal of Physics B; Atomic, Molecular and Optical Physics, 54(14), p.145003_1 - 145003_8, 2021/07
Times Cited Count：0 Percentile：0.01(Optics)Two-color two-step photoionization optogalvanic spectroscopy was performed using high-repetition-rate titanium sapphire lasers and a uranium hollow cathode lamp to find the two-step resonance ionization schemes of uranium. Many ionization transitions were observed by exciting uranium atoms in a ground state into five, even parity, excited levels with the first-step laser and by scanning the second-step laser wavelengths. By blocking the first-step laser, single-color, two-photon ionization transitions were also identified. From these results, we have found more than 50 odd-parity autoionizing levels of uranium in the energy, ranging from the ionization potential (49958.4 cm
) to 51150 cm. The determined energy levels are within 1 cm of previously reported values.
Hasegawa, Noboru; Nishikino, Masaharu; Tomita, Takuro*; Onishi, Naofumi*; Ito, Atsushi*; Eyama, Tsuyoshi*; Kakimoto, Naoya*; Izutsu, Rui*; Minami, Yasuo*; Baba, Motoyoshi*; et al.
X-Ray Lasers and Coherent X-Ray Sources; Development and Applications XI (Proceedings of SPIE, Vol.9589), p.95890A_1 - 95890A_8, 2015/09
Times Cited Count：1 Percentile：55.52(Optics)We have improved a soft X-ray laser (SXRL) interferometer synchronized with a Ti:Sapphire laser pulse to observe the single-shot imaging of the nano-scaled structure dynamics of the laser induced materials. By the precise imaging optics and double time fiducial system having been installed, the lateral resolution on the sample surface and the precision of the temporal synchronization between the SXRL and Ti:Sapphire laser pulses were improved to be 700 nm and 2 ps, respectively. By using this system, the initial stage (before 200 ps) of the ablation process of the Pt surface pumped by 80 fs Ti:Sapphire laser pulse was observed by the comparison between the soft X-ray reflective image and interferogram. We have succeeded in the direct observation of the unique ablation process around the ablation threshold such as the rapid increase of the surface roughness and surface vibration.
Inogamov, N. A.*; Zhakhovsky, V. V.*; Hasegawa, Noboru; Nishikino, Masaharu; Yamagiwa, Mitsuru; Ishino, Masahiko; Agranat, M. B.*; Ashitkov, S. I.*; Faenov, A. Y.*; Khokhlov, V. A.*; et al.
Applied Physics B, 119(3), p.413 - 419, 2015/06
Times Cited Count：6 Percentile：34.43(Optics)Ueda, Yoshio*; Oya, Kaoru*; Ashikawa, Naoko*; Ito, Atsushi*; Ono, Tadayoshi*; Kato, Daiji*; Kawashima, Hisato; Kawamura, Gakushi*; Kenmotsu, Takahiro*; Saito, Seiki*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 88(9), p.484 - 502, 2012/09
no abstracts in English
Kawachi, Tetsuya; Hasegawa, Noboru; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Oba, Toshiyuki; Kaihori, Takeshi; Kishimoto, Maki; Ochi, Yoshihiro; Tanaka, Momoko; et al.
X-Ray Lasers 2010; Springer Proceedings in Physics, Vol.136, p.15 - 24, 2011/12
This paper reviews recent improvement in the source development of laser-driven X-ray lasers and the applications in the research fields of material science, laser processing, X-ray imaging, and radiation damage in biological cells. In the application for material science, we have firstly observed temporal correlation between the domain structures of ferro-electric substance under the Curie temperature. In the laser processing, new X-ray laser interferometer reveals us the nano-scale surface distortion of substance pumped by a femto-second optical pulse. In the X-ray diffraction image, we have taken several static images of micro-structure of samples: now we are trying to extend the objective to nano-scale dynamics using pump and probe method. In the radiation damage of biological cells, we observed double strand break in DNA using X-ray laser exposure; this results are compared with the case using incoherent several KeV X-ray exposure.
collisions at 
= 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：184 Percentile：99.44(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：8 Percentile：49.7(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
+ collisions at = 200 GeV and scaling properties of hadron productionAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Y.*; Al-Bataineh, H.*; Alexander, J.*; Aoki, K.*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review D, 83(5), p.052004_1 - 052004_26, 2011/03
Times Cited Count：175 Percentile：98.48(Astronomy & Astrophysics)The PHENIX experiment at RHIC has measured the invariant differential cross section for production of 
, 
, 
and 
mesons in collisions at = 200 GeV. The spectral shapes of all hadron transverse momentum distributions are well described by a Tsallis distribution functional form with only two parameters, 
and 
, determining the high 
and characterizing the low regions for the spectra, respectively. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.
Koizumi, Satoshi; Zhao, Y.; Tomita, Yoko*; Kondo, Tetsuo*; Iwase, Hiroki; Yamaguchi, Daisuke; Hashimoto, Takeji
European Physical Journal E, 26(1-2), p.137 - 142, 2008/05
Times Cited Count：55 Percentile：86.02(Chemistry, Physical)no abstracts in English
Tomita, Yukihiro*; Smirnov, R.*; Chutov, Y.*; Takayama, Arimichi*; Takizuka, Tomonori
Contributions to Plasma Physics, 44(1-3), p.162 - 167, 2004/04
Times Cited Count：2 Percentile：6.49(Physics, Fluids & Plasmas)Electrostatic potential formation due to negatively charged dust particles near a divertor plate is studied by one-dimensional kinetic analysis. It is shown that the negatively charged dust particles reduce the ion-sheath potential drop in front of the plate. Dust particles with a large radius (100 micron) reduce the potential drop significantly despite the low dust-to-plasma density ratio (
10to-8). The plasma particle flux is reduced appreciably by the absorption by the dust particles.
Smirnov, R.*; Tomita, Yukihiro*; Takizuka, Tomonori; Takayama, Arimichi*; Chutov, Y.*
Contributions to Plasma Physics, 44(1-3), p.150 - 156, 2004/04
Times Cited Count：10 Percentile：32.04(Physics, Fluids & Plasmas)Dynamics of dust particles in a divertor plasma is simulated using numerical solutions of dust momentum and charging equations in an electrostatic sheath and an ionizing presheath. Spatial distribution of plasma parameters in a divertor are obtained with particle simulations including ionization by electron-impact. We found that dust particles with a larger radius are incapable to come off a divertor plate. Middle-size dust particles come off the plate but come back to the plate. Smaller dust particles come off the plate and reach an equilibrium position in the divertor plasma.
Tomita, Yukihiro*; Smirnov, R.*; Chutov, Y.*; Takayama, Arimichi*; Takizuka, Tomonori
Purazuma, Kaku Yugo Gakkai-Shi, 6, p.429 - 432, 2004/00
Formation of an electrostatic potential due to negatively charged dust particles near a target plate was studied by one-dimensional kinetic analysis. Immovable dust particles are distributed uniformly inside a system. It is clarified that the negatively charged dust particles reduce the ion-sheath drop. A threshold dust density makes the electric field at the target plate zero. The stationary oscillation appears in the electrostatic potential for the dust density above the threshold. We confirm that this oscillation is the Dust Ion-Acoustic Wave with a wave length of the order of Debye length, where dust charges are effective to determine the coefficient.
Smirnov, R.*; Tomita, Yukihiro*; Takizuka, Tomonori; Takayama, Arimichi*; Chutov, Y.*
Purazuma, Kaku Yugo Gakkai-Shi, 6, p.752 - 755, 2004/00
Dynamics of a single dust particle in near-wall plasma is studied in wide range of dust radii and masses. Dust motion and charging equations are solved in the plasma simulated for sheath and ionizing presheath using one-dimensional particle model. It was found that balance of electric and ion drag forces acting on the dust particle provides two critical dust radii differentiating motion of dust started at the wall between pinned against the wall, short and long-range oscillating. Delayed charging causes the mass dependence of the second critical radius until transition from short to long-range oscillations becomes undistinguishable.
Smirnov, R.*; Tomita, Yukihiro*; Takizuka, Tomonori; Takayama, Arimichi*; Chutov, Y.*
NIFS-784, 9 Pages, 2003/10
Dynamics of dust particles in a divertor plasma is simulated using numerical solutions of dust momentum and charging equations. Spatial distributions of plasma parameters in a divertor are obtained with particle simulations including electron-impact ionization. We find that the large-radius dust particles are not released from the divertor plate. The middle-size-radius particles are released but retuned to the plate. The small-radius particles can be released from the plate.
Ni+
Ni and 
Ni+
Ni around the coulomb barrierSugiyama, Yasuharu; Tomita, Yoshiaki; Yamanouchi, Y.; Hamada, S.; *; Fujita, H.*; D.R.Napoli*
Physical Review C, 55(1), p.R5 - R7, 1997/01
Times Cited Count：6 Percentile：38.42(Physics, Nuclear)no abstracts in English
C(
O,C[2
])OSugiyama, Yasuharu; Tomita, Yoshiaki; Ikezoe, Hiroshi; Yamanouchi, Y.; Ideno, K.; Hamada, S.; Hijiya, M.*; Sugimitsu, Tsuyoshi *; Mukae, T.*; Nakamoto, K.*; et al.
Physical Review C, 49(6), p.3305 - 3308, 1994/06
Times Cited Count：3 Percentile：18.28(Physics, Nuclear)no abstracts in English
O + O system at E
=145MeVSugiyama, Yasuharu; Tomita, Yoshiaki; Ikezoe, Hiroshi; Yamanouchi, Y.; Ideno, K.; Hamada, S.; Sugimitsu, Tsuyoshi *; Hijiya, M.*; *
Physics Letters B, 312(1-2), p.35 - 39, 1993/08
Times Cited Count：38 Percentile：87.64(Astronomy & Astrophysics)no abstracts in English
Zhao, Y.; Koizumi, Satoshi; Hashimoto, Takeji; Tomita, Yoko*; Kondo, Tetsuo*
no journal, ,
Koizumi, Satoshi; Tomita, Yoko*; Zhao, Y.; Iwase, Hiroki*; Yamaguchi, Daisuke; Kondo, Tetsuo*; Hashimoto, Takeji; Masui, Tomomi
no journal, ,
no abstracts in English
Zhao, Y.; Koizumi, Satoshi; Hashimoto, Takeji; Tomita, Yoko*; Kondo, Tetsuo*
no journal, ,
