Jerry Seidler: What is X-ray Raman Scattering, and What Did Raman Have to Do With It?
X-ray Raman Scattering (XRS, often also called nonresonant inelastic x-ray scattering), is a hard x-ray alternative to soft x-ray NEXAFS. I'll review the basic physics, including the role of momentum transfer to tune selection rules. And I'll explain Raman's involvement, or lack thereof. References: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.74.214117 and https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.105.053202 https://www.youtube.com/watch?v=kuKA81-R7-w
Simo Huotari: X-ray Raman spectroscopy: glimpse of the state of the art for samples in complex environments
In this lecture I will continue where the previous lecture ends and talk about some examples of how XRS is used to study materials under high pressure and chemical reactions. References: https://www.nature.com/articles/nmat3031 and https://pubs.acs.org/doi/abs/10.1021/jp912208v https://www.youtube.com/watch?v=mGD3HqwaitU&t=1205s
Evan Jahrman Core-to-core X-ray Emission Spectroscopy: Pitfalls and Advantages for Lab-based and Synchrotron Users
Core-to-core X-ray emission spectroscopy (CTC-XES) has not only provided key insights into atomic physics but is extremely well positioned to serve as a major analytical technique for several materials systems in the coming decades. Moreover, CTC-XES frequently serves as an enabling phenomenon for more exotic varieties of synchrotron-based XAFS. I will cover several applications of […]
Adam Hitchcock: Soft X-ray Spectromicroscopy in Scanning Transmission X-ray Microscopes
Soft X-ray scanning transmission microscopy (STXM) is a powerful tool for nanoscale materials analysis, with significant advantages over analytical electron microscopies for studies of radiation sensitive materials. Chemical species identified by near edge X-ray absorption fine structure (NEXAFS) spectra can be mapped quantitatively in 2D and in 3D. STXM instrumentation and methods will be described, […]
Kelsey Morgan: Hot science with cool sensors
The transition-edge sensor (TES) microcalorimeter uses the sharply temperature-dependent resistance of the superconducting transition to measure the energy of X-ray and gamma ray photons. A single TES is a broadband, energy-dispersive area detector capable of eV-scale energy resolution with good quantum efficiency. With an array of hundreds or thousands of sensors, a TES-based spectrometer can […]
Martin McBriarty: Top-Down Approaches to EXAFS Analysis
EXAFS spectra are often modeled using a small number of virtual coordination shells which can vary in coordination number, bond length, and disorder. While this bottom-up approach is generally successful for single-phase samples, it becomes intractable when the element of interest occupies multiple complex coordination states. Such cases may require a top-down approach, in which […]
Steve Heald: Sector 25 at the APS-U: Two new beamlines for advanced spectroscopy
As part of the Advanced Photon Source (APS) Multibend Achromat lattice upgrade two new beamlines for spectroscopy will be constructed on a canted undulator source at Sector 25. The programs at the 20-ID beamline at the APS need to move to sector 25 to make room for a planned long beamline. These will be combined […]
Neil Hyatt: Multimodal microfocus XAS to understand and remediate DU munitions contamination
The talk will show how multimodal microfocus X-ray spectroscopy has been applied to characterize depleted uranium particles from munitions testing to predict and understand their environmental behavior. A combination of spatially resolved XRD, XRF and XAS techniques, combined with laboratory SEM observations, is shown to effectively differentiate DU particulate contamination in near surface and burial […]
Jacinto Sa: Solving chemical mechanisms with X-ray spectroscopy
As a scientist have been always fascinated with how chemical systems react and interact with the natural world. Spectroscopy is a great tool to look at systems in real-time and operation conditions. Hard X-ray photon-in photon-out spectroscopy offers great possibilities due to its chemical sensitivity and speciation as well as high penetration. In this webinar, […]
Yulia Pushkar: X-ray Emission Spectroscopy at X-ray Free Electron Lasers: Limits to Observation of Unperturbed Electronic Structures
Modern free electron lasers provide intense X-ray pulses with 10^12 photons within ~10-100 femtoseconds. Such pulses enable new experimental techniques and provide unique opportunities for investigation of electronic and nuclear dynamics on their intrinsic time-scales. Interaction of ultra-bright, ultra-short X-ray pulses with matter can induce a multitude of nonlinear excitation processes which must be carefully […]
Rene Bes: Nuclear fuel study using XAS: benefits of HERFD for U valence states evaluation
The safe use and disposal of UO2 based nuclear fuels relies on the stability of their material properties, under extreme conditions of temperature and irradiation, and with constantly evolving chemical composition. Among them, the uranium valence state’s behavior is at the heart of safety assessment during the entire fuel lifecycle. First, the oxidation from UO2 […]
Joe Fowler: X-ray Fluorescence Line Metrology for the 21st Century
Databases of x-ray fluorescence line energies such as those of Deslattes (2003) and Bearden (1967) are critical to the calibration of any analytical tools that identify elemental compositions by their x-ray “fingerprints.” To be useful, such tables have to favor completeness over accuracy. Unfortunately, a full 75% of the lines in the current NIST database […]