Optimization of compact Soller collimator
  The opportunity of optimization of collimator was investigated by changing collimator length, material and wall roughness for soft x-ray radiation with wavelength 4 nm corresponding to carbon atoms absorption. From the obtained results follows that effects of diffraction become significant for channel widths up to 0.02 - 0.04 mm. Collimation angle was limited to 0.014 and 0.007 radian for carbon dust detection. The choice of lighter material with greater height of roughness in shorter collimator with 2 reflections results in considerably lower losses than for heavier materials and smoother walls where 4 reflections required. 
L.I.Ognev