A New Method to Determine the Orientations of Crystal Defects by Synchrotron Radiation

Abstract: A new method was put forward to determine the orientations of crystal defects by synchrotron radiation.Instead of using monochromic radiation as it was done before,a simple method was proposed using white radiation to calculate directions of crystal defects.In order to do so,at least two topographs with different beam incident directions were needed.The direction of an image of a defect should be figured out first.It can be fixed by the angles between the direction of the image and [100],[010]and [001].Suppose the direction of the topograph is [u₁ v₁ w₁]and the direction of the image in the first topograph is [cosα₁₁,cosβ₁₁,cosγ₁₁],α₁₁,β₁₁ and γ₁₁ are the angles between the image and [100],[010] and [001],respectively,then the direction of the defect should be in thd plane with normal n₁=[u₁ v₁ w₁]×[cosα₁₁,cosβ₁₁,cosγ₁₁].Similarly,in the second topograph,the normal of the plane in which the same defect lies is n₂=[u₂ v₂ w₂]×[cosα₁₂,cosβ₁₂,cosγ₁₂],in which [u₂ v₂ w₂] is the direction of the second topograph,α₁₂,β₁₂, and γ₁₂ are the angles between the direction of the image and [100],[010] and [001].Since the defect are normal to n₁ and n₂,its direction n can be calculated out as n=n₁×n₂=[u v w].Using this method,the directions of dislocations in natural diamond were calculated and the types of the dislocations were figured out.