Development of X-ray NaNo-focusing System with Tunable Focus using a Combination of Capillary Mirror Lens with Multilayer Laue Lens (MLL)

The increasing complexity of modern materials and devices and the progression of research in disciplines such as the life science and energy materials science has driven the critical desire for analytical tools to obtain heterogeneity information across the length scales, ranging from macroscopic scale down to the nanometer level. X-ray nanofocusing systems at synchrotron particle accelerators provide major analytical advantages and are frequently required to conduct leading-edge research. The limited availability of time at such systems is a major impediment to scientific progress. There is a need for a solution that increases synchrotron beamline efficiency and capacity available by making existing nanofocusing systems more efficient and enables cost-effective upgrades of lower resolution synchrotron systems to enable multi-length scale analysis capabilities that reach down to resolution at 10s of nanometer. The proposed x-ray nanofocusing system will couple two major recent optical development breakthroughs. The first is that of a bonded Multilayer Laue lens (MLL) which can provide high efficiency focusing down to 10 nm resolution but requires matching the phase space of the x-ray source to that of the MLL, which limits the efficient use of x-rays provided by the synchrotron. The second is a capillary x-ray mirror lens developed by the proposing company that provides extremely high-efficiency focusing with microns-scale resolution and large phase space. By coupling the capillary x-ray mirror lens as a pre-focusing optic upstream of the MLL, a high efficiency nanofocusing system can be developed that will provide high flux, at flexible, tunable x-ray spot sizes from submicron to 50-100 nm for synchrotron systems, enabling more efficient use of synchrotron beamtime and cost-effective upgrades. Phase I achieved the completion of and testing of a prototype nanofocusing system: a matched 1D MLL and capillary x-ray mirror lens were fabricated, staging was designed and built for aligning the two components, and an alignment procedure was developed. To verify the expected demagnification capabilities of the nanofocusing system, a laboratory x-ray source with a molybdenum target was focused by the system onto a CCD detector. The results showed substantial demagnification, but also pointed to a few issues inherent in a laboratory testing environment that would be absent at the synchrotron, caused by x-ray divergence and chromatic aberrations from the two molybdenum K-alpha characteristic lines. Phase II will develop a set of capillary mirror lenses and a 2D bonded MLL with substantially higher performance than in Phase I, a computer controlled electromechanical system for switching between resolution modes in the nanofocusing system analogous to objectives on an optical microscope, and successful demonstrations at the laboratory and at the synchrotron of the focusing power and flux of the system. Commercial Applications and Other Benefits: This nanofocusing system will be commercialized both as a system sold directly to synchrotron and laboratory instrumentation development groups and as the key enabling component of a laboratory microXRF system with sub-micrometer resolution. Synchrotron and laboratory systems incorporating the proposed optical system will make nano-focusing x-ray analysis capabilities dramatically more accessible, which will accelerate the research on many emerging topics including: batteries, semiconductors, nanoparticles, and pharmaceuticals. Moreover, the proposed system can be used to provide more complete multi-length scale models to better understand complex features at a range of important microscopic scales (microns to nanometers).