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Brilliant synchrotron radiation (SR) has enabled us to investigate fast phenomena even in small samples. At the same instance, the property of sample may be affected by the SR due to the high brilliance. An SR X-ray pump and optical probe measurement has then been performed at a storage ring facility of SPring-8 to investigate the spectral change in the near infrared region of a GaAs single crystal irradiated by an intense X-ray pulsed SR beam with a photon energy of just above the K-edge of As. The transient transmission spectrum was monitored by using a broadband optical pulsed beam and a dispersive spectrometer. We obtained the spectral profile change with a response time of shorter than the pulse duration of SR. The spectrum shows the abrupt change in transmittance at around 880 nm corresponding to the band gap energy of GaAs, and the fringe on the spectrum originated from the interference at the sample with a thickness of about 10μm. The band gap energy and the fringe shift to the opposite direction to each other, the behavior of which is explained to be due to the band gap shrinkage accompanied with the decrease of refraction index originated from the free carriers. The transient band gap shrinkage suggests the nonthermal lattice distortion induced by SR irradiation. [ABSTRACT FROM AUTHOR]

Fiber optics for controlling the x-ray beam trajectory has been examined at the synchrotron facility of SPring-8. Up to now, we have achieved beam deflection by several tens of milli-radian and axis shift of around 75 mm with a 1.5 m-long flexible hollow glass capillary. The achievable beam deflecting angle, axis shift, and timing delay are, in principle, proportional to the length, the square of length and the cube of length, respectively. Thus, for further applications, requiring larger beam shift and pulse delay, longer fibers are indispensable. In order to achieve longdistance transport using the fiber, we thus examined the connection transferring x-rays between fibers in an experimental hutch. The acceptance angle at the input end and the throughput efficiency of the second fiber is consistent with the consideration of the output beam divergence of the first fiber. The enhancement of the transfer efficiency is also discussed for the cases of a closer joint and the use of a refractive lens as a coupler. [ABSTRACT FROM AUTHOR]