Production of tunable monochromatic x rays by the Vanderbilt free-electron laser

摘要

Abstract: Sustained/long duration X-ray output has been demonstrated emanating from the monochromatic X-ray beamline of the Vanderbilt Free-Electron Laser. Tunable, pulsed monochromatic X-rays ranging in energy from 14 - 18 keV are produced by inverse Compton scattering created by the counter propagation of the FEL e-beam and its own infrared beam. These beams are focused and optimized at an interaction zone between the linac and the wiggler where they are brought into coalignment. The X-rays produced exit the beamline through a beryllium window and are directed onto mosaic crystals which divert the beam to an imaging laboratory on the floor above the vault. The initial application of these X-rays is directed toward human imaging, specifically for the diagnosis of breast diseases including cancer. The characteristics of the X-rays are such that they can be used in standard geometry monochromatic imaging, CT like images of the breast using a rotating mosaic crystal 'optic,' time-of-flight imaging and phase contrast images. Eventual extension to other portions of the body, cell biology and material sciences are already anticipated. !15