Scanning and transfer of cryogenic samples in the BioNanoProbe-II instrument at the Advanced Photon Source

A new hard x-ray fluorescence (XRF) nanoprobe in-strument called Bionanoprobe-II (BNP-II) has been designed and will be constructed at 2-ID-D of the up-graded Advanced Photon Source. BNP-II will take ad-vantage of the orders-of-magnitude increase in bright-ness and coherent flux with advanced sample scanning, metrology, cryogenics, and controls. These advancements will enable high-throughput XRF imaging under cryogenic conditions with 10 nm spatial resolution, 2D survey of mm-sized samples, and fast tomography for 3D visualization. BNP-II also introduces a novel robotic sample transfer system that interconnects a cryogenic plasma focused ion beam (cryo-PFIB) milling station alongside the x-ray nanoprobe. The interconnected instruments enable an iterative workflow between x-ray measurements and cryo-PFIB milling and maintains the integrity of vitrified samples by remaining below 110 K even during transfer. Regions of interest can be identified by fast large-area scans, after which the sample geometry can be optimized for nanoscale x-ray imaging and tomography. This work details the engineering advancements required to examine highly complex, multidimensional systems with BNP-II.