Workshop on Science with High-Energy X-rays
August 9-10 , 2004, APS, Argonne, Illinois
Scope:
The synchrotron radiation facilities based 6-8 GeV storage rings are well suited to deliver high-energy x-rays in the 50 keV to 500 keV range. The high energy x-rays not only penetrate through highly dense materials, but with the wavelength being shorter than the inter-atomic separation in materials, the processes involved in their interaction with matter change. Hence when the traditional x-ray scattering and absorption techniques are used with high energy x-rays one obtains newer insights in to material science. For example, diffuse scattering measurements will permit a quantitative analysis of several Brillouin zones since the Ewald sphere is flat at high x-ray energies. The complex terms in the x-ray magnetic scattering cross-section are simplified when the x-ray energy is high, thus simplifying the data analysis on magnetic structures. High-energy x-rays can penetrate deeply into a sample and can be used to measure true bulk properties. Also, they can probe through environmental chambers that are inaccessible to lower energy x-rays, allowing for experiments in extreme conditions and for many types of in situ studies. In many cases, high-energy x-rays have penetration capabilities comparable to neutrons, but with much better spatial resolution and considerably higher flux. Examples of high-energy x-ray research include measurements of stress/strain in materials, powder diffraction of compounds containing heavy elements, diffuse scattering of defects in complex oxides, pair-distribution-function measurements of amorphous materials, and high-energy small-angle scattering from thermal-barrier coatings.
The workshop focused on thefollowing topics:
- Interaction of high energy x-rays with matter
- Unique applications of high energy x-rays in material science, atomic science, chemical science and industrial applications.
- Science at extreme environments
The user demand for high-energy x-ray experiments is growing rapidly, and current capabilities for some of the techniques are heavily oversubscribed. Opportunities exist to further enhance the high-energy x-ray capabilities at the APS through optimization of optics and insertions devices, and through the development of dedicated instrumentation. Such optimization will increase the available high-energy flux by more that an order of magnitude.
The purpose of this workshop was to explore the emerging scientific opportunities using high energy x-rays, and to seek input from both instrumentation experts and interested scientists on possibilities for the development of future high-energy x-ray facilities at the APS.
