Studies on focusing performances of the bent crystal monochromator

The triangular crystal is used as monochromator on 4W1C beamline at Beijing Synchrotron Radiation Facility. Three crystals of Si(I11), Si(220) and Si(422) with an oblique-cut angle of 12.16 degree are employed at the same Bragg angle 23.65 degree to select monochromatic X-rays with wavelengths of 0.252 nm, 0.154 nm and 0.089 nm, respectively. The triangular crystal is bent to a cylindrical shape to focus the beam in the horizontal direction and to provide focusing monochromatic X-rays for the diffuse scattering station. The theoretic calculations and SHADOW ray-tracing of the optical system are in good agreement with the experimental results