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Tanaka, Momoko; Furukawa, Yusuke*; Nakazato, Tomoharu*; Tatsumi, Toshihiro*; Murakami, Hidetoshi*; Shimizu, Toshihiko*; Sarukura, Nobuhiko*; Nishikino, Masaharu; Kawachi, Tetsuya; Kagamitani, Yuji*; et al.
X-Ray Lasers 2008; Springer Proceedings in Physics, Vol.130, p.501 - 505, 2009/00
We measured the time-resolved fluorescence spectra of ZnO and GaN single crystals excited by an X-ray laser operating at 13.9 nm and evaluated their scintillation properties for EUV excitation as compared with UV excitation case. For ZnO, a clear fluorescence peak of excitonic origin was observed at around 380 nm and the decay lifetime of less than 3 ns is found to be almost similar to the UV excitation case. The fluorescence at 380 nm is ideal for scintillator device design in the EUV and further applications. For GaN, the lifetimes are much longer than ZnO and the temporal profile of the EUV-excited fluorescence differs with the UV excitation case. As such, the EUV scintillation properties of ZnO is said to be more favorable than GaN. Finally, it is also demonstrated that an X-ray laser is an excellent tool for spectroscopic characterization of materials intended for next-generation lithography applications.
Nishikino, Masaharu; Yamatani, Hiroshi; Nagashima, Keisuke; Kawachi, Tetsuya
X-Ray Lasers 2008; Springer Proceedings in Physics, Vol.130, p.427 - 432, 2009/00
The focused X-ray beam with a high intensity and a micron-order scale is expected to open various fields, such as the nonlinear phenomena, the nanoscale structuring of semiconductor material, and the X-ray probing of a single biological cell. A submicron soft X-ray beam is generated by a highly coherent soft X-ray laser at 13.9 nm with a Fresnel phase zone plate (FZP). The focused X-ray beam profile is measured using a knife-edge scan method. The submicron X-ray beam can also be used as the X-ray source of the Fourier transform holography. The FZP generates a point reference source and works as a beam splitter. The transmitted 0th order beam illuminates the object directly. A Fourier transform hologram is generated by the interference between the object wave diffracted from the object and the spherical reference wave. The holograms of the wire and the grid pattern are recorded with a CCD camera. The spatial resolution of the hologram will be presented.
Ochi, Yoshihiro; Hasegawa, Noboru; Kawachi, Tetsuya; Nishikino, Masaharu; Tanaka, Momoko; Kishimoto, Maki; Oba, Toshiyuki
X-Ray Lasers 2008; Springer Proceedings in Physics, Vol.130, p.161 - 166, 2009/00
Daido, Hiroyuki
no journal, ,
Kawachi, Tetsuya; Kishimoto, Maki; Kado, Masataka; Tanaka, Momoko; Hasegawa, Noboru; Ochi, Yoshihiro; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kunieda, Yuichi; et al.
no journal, ,
Recent progress in X-ray laser research in Japan Atomic Energy Agency is reviewed. Using the nickel-like silver soft X-ray laser at the wavelength of 13.9 nm, the application experiments have been conducted in the research fields such as material science, high-density plasma diagnostics, XRL ablation, XRL imaging using single-shot holography and atomic physics. The repetition rate of the XRL beam has been improved from each 10-20 minutes to 0.1 Hz by using new driver laser system with Nd: glass zigzag slab amplifier, and we are now constructing new beam line for the pump-probe measurement of the surface phase-transition by the method of X-ray laser interferometer. In the research activity on the extension of the wavelength region of the X-ray lasers, firstly, the demonstration of novel coherent X-ray generation by "flying mirror" technique is reported. The second is theoretical investigation of the resonance photo-pumping scheme toward water-window region.
