ABSTRACT
A high-flux sub-micrometre focusing system was constructed using multilayer focusing mirrors in Kirkpatrick-Baez geometry for 100â keV X-rays. The focusing mirror system had a wide bandwidth of 5% and a high peak reflectivity of 74%. Performance was evaluated at the undulator beamline BL05XU of SPring-8, which produced an intense 100â keV X-ray beam with a bandwidth of 1%. When the light source was focused directly in both vertical and horizontal directions, the beam size was measured to be 0.32â µm (V) × 5.3â µm (H) with a flux of 1 × 1012â photonsâ s-1. However, when a limited horizontal slit was used to form a secondary source, the focusing beam size decreased to 0.25â µm (V) × 0.26â µm (H) with a flux of 6 × 1010â photonsâ s-1. The 200â nm line and space patterns of a Siemens star chart made of tantalum were clearly resolved by the absorption contrast of the focused beam. This 100â keV focusing system is applicable to various fields of nondestructive analyses with sub-micrometre resolutions.
ABSTRACT
In this study, double-multilayer monochromators that generate intense, high-energy, pink X-ray beams are designed, installed and evaluated at the SPring-8 medium-length (215â m) bending-magnet beamline BL20B2 for imaging applications. Two pairs of W/B4C multilayer mirrors are designed to utilize photon energies of 110â keV and 40â keV with bandwidths of 0.8% and 4.8%, respectively, which are more than 100 times larger when compared with the Si double-crystal monochromator (DCM) with a bandwidth of less than 0.01%. At an experimental hutch located 210â m away from the source, a large and uniform beam of size 14â mm (V) × 300â mm (H) [21â mm (V) × 300â mm (H)] was generated with a high flux density of 1.6 × 109 photons s-1 mm-2 (6.9 × 1010 photons s-1 mm-2) at 110â keV (40â keV), which marked a 300â (190) times increase in the photon flux when compared with a DCM with Si 511 (111) diffraction. The intense pink beams facilitate advanced X-ray imaging for large-sized objects such as fossils, rocks, organs and electronic devices with high speed and high spatial resolution.