Unidirectional x-ray output from a crystal waveguide affected by Berry's phase.

We show momentum-space characteristics of X-rays affected by Berry's phase in a deformed crystal, allowing a 15 keV beam inside a silicon crystal to be translated parallel to its optical axis while retaining its angular divergence and wave front. This data is the first evidence supporting the whole theoretical picture of Sawada et al., Phys. Rev. Lett. 96, 154802 (2006), consisting of two equations of motion about the X-ray propagation. An output beam was as much as 3.3% of the incident after propagating through 1.3 mm silicon along a lateral direction of the chip inclined at 17.722°. As its initial practical application we further utilized the device as an X-ray intensity modulator. Our results revealed a new aspect of the Berry phase and lead to an X-ray waveguide that can enhance the flexibility of future high-energy experiments.

X-ray collimation by the parabolic cylinder mirror in SPring-8/BL29XUL.

A combination of plane and threefold-shape X-ray mirrors was installed in SPring-8 BL29XUL. The second mirror has parabolic cylinder surfaces that collimate X-rays in the vertical direction. A performance test was conducted, yielding highly collimated 8 keV photon beams with an effective angular divergence of 0.4 µrad, below only 5% of that of the original beams. The double-mirror system preserved 70% of the total incident flux and nearly tripled the flux density at 988 m from the light source. The values of the observations were almost similar to those of our ray-tracing simulation. Based on the results a discussion of future prospects of the mirror system is included.

X-ray polarimeter with a transmission multilayer.

We fabricated a novel x-ray polarimeter with a transmission multilayer and measured its performance with synchrotron radiation. A self standing multilayer with seven Mo/Si bilayers was installed with an incident angle of 45 degrees in front of a back-illuminated CCD. The multilayer can be rotated around the normal direction of the CCD keeping an incident angle of 45 degrees. This polarimeter can be easily installed along the optical axis of x-ray optics. By using the CCD as a photon counting detector with a moderate energy resolution, the polarization of photons in a designed energy band can be measured along with the image. At high photon energies, where the multilayer is transparent, the polarimeter can be used for imaging and spectroscopic observations. We confirmed a modulation factor of 45% with 45% and 17% transmission for P- and S-polarization, respectively.