Polycapillary Optics for in Situ Diagnostics

Abstract

ABSTRACTPolycapillary optics, shaped arrays consisting of hundreds of thousands of hollow glass capillary tubes, are used to redirect, collimate, or focus x-ray beams from conventional laboratory-based sources. Focused spot sizes as small as 20μm have been measured, with flux densities two orders of magnitude larger than that produced by pinhole or crossed slit collimation. Such flux increases have made possible faster and more sensitive x-ray fluorescence (XRF) and diffraction measurements to the extent that in situ measurements become possible. XRF data taken with a 12 W source were comparable to data taken with a 1.5 kW source. Ex situ diffraction and texture measurements on thin multilayered films and single crystal silicon demonstrate the tremendous experimental and analytical improvements made possible by polycapillary optics.With 0.5° and 2° focusing polycapillary x-ray optics, diffraction intensity gains of more than two orders of magnitude were measured on small Lysozyme protein crystals with exposure times an order of magnitude less than required by traditional measurement techniquesIn addition, the optics greatly reduce the background high energy Bremsstrahlung, permitting more accurate analysis of thin complex multilayer diffraction peaks. Rapid measurement times resulting from the application of these polycapillary optics, indicate tremendous possibilities for in situ process monitoring