X-ray characterization of low strain HPHT synthetic diamond crystals

This study uses x-ray characterisation experiments to understand material science issues at the current extremes of high purity and low strain in synthetic type IIa HPHT diamond. This type of diamond has impurities below 10ppb and large areas where the effective misorientation (the deviation of the local Bragg angle in the deformed parts of the crystal from the one in the perfect region) of the lattice in the region of 10¿8. The first goal was therefore to characterise the type IIa HPHT synthetic diamonds in this limit of high purity and low strain, and understand the nature of the defects and their contribution to long range strains. It has emerged that this is a nontrivial task, and will necessitate the deployment of x-ray techniques which are extremely sensitive. This research offers a unique opportunity to understand diamond material science in the realm of low strain crystals. It is envisaged that the essential simplicity of the defects and the purity of the material will enable reproducible experiments which are tractable to theoretical interpretation. This has long been a goal of diamond physics.