A next-generation x-ray beamline, now operating at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) (Berkeley, California, USA), is bringing together unique capabilities to measure the nanoscale properties of materials.
Called COSMIC, for coherent scattering and microscopy, this x-ray beamline at Berkeley Lab’s Advanced Light Source (ALS) synchrotron facility allows scientists to probe working batteries and other active chemical reactions, and reveal new details about magnetism and correlated electronic materials. COSMIC has two branches that focus on different types of x-ray experiments: one for x-ray imaging experiments and one for scattering experiments. In both cases, x-rays interact with a sample and are measured to find structural, chemical, electronic, or magnetic information about samples. COSMIC’s low-energy x-rays are especially well-suited for analyzing chemical composition within materials, ALS researchers say.
Scientists have already used the COSMIC system's imaging capabilities to explore a range of nanomaterials, battery anode and cathode materials, cements, glasses, and magnetic thin films. As part of that program, researchers recently published a study demonstrating results from a technique known as ptychographic computed tomography that created a three-dimensional (3-D) map of the location of chemical reactions inside lithium-ion batteries. “We looked at a piece of a battery cathode in 3-D with a resolution that was unprecedented for x-rays,” says Young-Sang Yu, an ALS scientist and lead author of the study. “This provides new insight into battery performance, both at the single-particle level and across statistically significant portions of a battery cathode.”
Researchers say the COSMIC x-ray beam is focused to a spot about 50 nm in diameter, while ptychography enhances the spatial resolution by a factor of 10 or more. The work in the study was performed with a 120-nm beam that achieved a 3-D resolution of ~11 nm. Combined with fast data detectors and real-time advanced algorithms, the system enables scientists to quickly reconstruct information from the data as they are collected.
Besides ptychography, researchers say the COSMIC platform is also equipped for experiments that use x-ray photon correlation spectroscopy, a technique that is useful for studying fluctuations in materials associated with exotic magnetic and electronic properties.
Going forward, the next step for beamline is the development of a new station with applied magnetic field and cryogenic capabilities, with early testing set to begin this summer. “We’re still in the mode of learning and tuning, but the performance is fantastic so far,” says David Shapiro, the lead scientist for COSMIC's microscopy experiments.
Source: Berkeley Lab, www.lbl.gov.