Simultaneous measurement of the reflectivity of X-ray with different orders of reflections and apparatus for measurement thereof

Disclosed are an apparatus and a method for simultaneously measuring integrated reflectivity of X-rays with different orders of reflections in crystal. Continuous X-rays are incident into the crystal and reflection intensities of the X-rays reflected from the crystal with different orders of reflections are measured based on Bragg's law, thereby measuring reflectivity of X-rays with different orders of reflections.