Principle of small angle X-ray scattering of cellulose microfibrils. a) Cellulose microfibrils in real space. Orientations are shown on the sample image at the upper right. Scale bar: 2 mm b) Fourier transform of the microfibrils are flat disks in reciprocal space that appear as two-dimensional scattering pattern on the detector (upper right). R: microfibril radius, L: microfibril length, μ: microfibril angle, α: cell wall orientation, χ: azimuthal peak positions in reciprocal space. Scalebar 2 mm. For simplicity only the calculated mean orientations are shown. Drawing adapted from .