Abstract by Chad Samuelson
Physics and Astronomy
Imaging strain at the nanometer scale with x-ray coherent diffraction imaging in order to make stronger materials
In this talk, I will discuss using the Brag nanometer scale, lensless imaging technique of x-ray Coherent Diffraction Imaging (CDI), known as Bragg CDI, to study the effects of strain on materials and their internal structure. Coherent X-ray or ‘laser-like’ beams interact with the material and then diffract differently depending on the granular structure of the material. The diffracted rays are measured on a detector that records the light intensity. I will present a simulation code that I developed. I will also discuss a research trip to the Argonne National Laboratory’s Advanced Photon Source (APS) in Chicago to perform strain imaging experiments on copper samples. The APS is an electron accelerator ring that accelerates electrons to near the speed of light. Coherent X-ray beams are created and used for experiments. We used the coherent X-ray beam at beamline 34ID-C to image a copper metal sample that was put under loading conditions causing strain to the material. The light source produced Bragg peaks. This pattern was recorded by our sensor and then run through a computer image reconstruction algorithm that determines the nanometer scale structure of the copper.