Anisotropy of x-ray scattering in aligned nanotube structures
  Effects of orientational x-ray scattering have been experimentally examined in a film of vertically aligned multiwall carbon nanotubes (CNs). Additional contribution to the x-ray fluorescence intensity was revealed at angles close to the film normal. Theoretical considerations suggest the intensity enhancement to be caused by propagation of C K$_{\alpha}$-radiation mainly along the channels of CNs. 
A.V. Okotrub, S.B. Dabagov, A.G. Kudashev, A.V. Gusel'nikov, L.G.   Bulusheva, A. Grilli