Date

5-31-2017

Document Type

Poster

Abstract

The High Energy Density Sciences group at SLAC National Accelerator Laboratory uses shock waves produced by the Linac Coherent Light Source to dynamically compress polycrystalline diamond samples. Compressing these polycrystalline samples allows us to use x-ray diffraction to study the changes to the structure as it experiences high pressure conditions. Polycrystalline diamond is valuable to study because it can be formed into ablator capsules for use in inertial confinement fusion reactions. As a result of the shock compression, the polycrystalline diamond samples undergo dynamic compression, a combination of stress and strain. To understand how dynamic compression takes place in a polycrystalline material, we can predict the changes in the x-ray diffraction pattern that occur from the compressed material. This predictive model uses the crystal grain size and orientation of our polycrystalline diamond samples as parameters. Procuring a precise measurement of the crystal grain size in our samples will allow us to make more accurate predictions of the changes to the diffraction pattern in order to understand how the diamond sample responds to dynamic compression. Analyzing images of the samples from a scanning electron microscope (SEM) can give us information about the crystal grain size. We determine that the diamond crystals in our sample are 18.91 nm in diameter on average and that our material is relatively uniform across all areas of each sample.

Major

Physics and Astronomy

Major / Minor

German

College / School

Weinberg College of Arts and Sciences

O.U.R. Funding

no

Faculty Advisor

Siegfried Glenzer

 
May 31st, 12:00 AM

Determining the grain size of polycrystalline diamond for high energy density experiments

The High Energy Density Sciences group at SLAC National Accelerator Laboratory uses shock waves produced by the Linac Coherent Light Source to dynamically compress polycrystalline diamond samples. Compressing these polycrystalline samples allows us to use x-ray diffraction to study the changes to the structure as it experiences high pressure conditions. Polycrystalline diamond is valuable to study because it can be formed into ablator capsules for use in inertial confinement fusion reactions. As a result of the shock compression, the polycrystalline diamond samples undergo dynamic compression, a combination of stress and strain. To understand how dynamic compression takes place in a polycrystalline material, we can predict the changes in the x-ray diffraction pattern that occur from the compressed material. This predictive model uses the crystal grain size and orientation of our polycrystalline diamond samples as parameters. Procuring a precise measurement of the crystal grain size in our samples will allow us to make more accurate predictions of the changes to the diffraction pattern in order to understand how the diamond sample responds to dynamic compression. Analyzing images of the samples from a scanning electron microscope (SEM) can give us information about the crystal grain size. We determine that the diamond crystals in our sample are 18.91 nm in diameter on average and that our material is relatively uniform across all areas of each sample.