Development of Capillary Optics Optimized for Soft X-ray Nano-focusing with 25nm Resolution

The advent of ultra-bright synchrotron and free-electron laser FEL) x-ray sources is bringing orders of magnitude higher peak brightness than previous generation synchrotrons. As concluded by the recent DOE BES light source workshop 2013), the ability to utilize these ultrabright sources is now limited by x-ray optics technology. The proposed project will develop ultrahigh resolution x-ray optic optimized for soft x-ray energies having axial symmetry for larger numerical aperture greater throughput) and focal spots down to 25nm. Such ultrahigh resolution optics are needed broadly in the synchrotron community, but nanofocusing is particularly an unmet need for soft x-ray techniques. The goal of Phase I is to validate a mandrel-based optics shaping technique based on the proprietary capillary x-ray optic shaping technique already developed. The current shaping process is based on a fabrication process that shapes the interior of a glass capillary and can achieve slope errors of less than 5 micro-radians. By focusing on shaping the exterior of the optic, a mandrel that can be used to replicate optics with aspect ratios larger opening and shorter length) can be developed. Refinement of the mandrel through etching to minimize slope errors can be achieved to ensure spot sizes on the order of tens of nanometers. Because Sigray already has the capability to form the mandrel through shaping, we consider the etching process to be the major feasibility test and will focus the tasks to achieve nanometer etching depth control using a jet of HF. The 25nm capillary lenses developed in this proposal will be commercialized as components for x-ray beamlines. Sigray has already commercialized paraboloidal and ellipsoidal optics and received over $1.5M in purchase orders from synchrotron customers worldwide, and the Wolter optics proposed would be of significant commercial value. In addition, the optics will be used as a key component in many of the proposing company’s suite of laboratory x-ray systems. Wolter optics offer ideal properties as x-ray imaging optics and will be particularly valuable for the company’s x-ray fluorescence and x-ray microscopy products.