User:ASelino16/sandbox

It is Wednesday, August 31, 2022, 11:51 AM. I am starting my Sandbox page.

Atomic Electron Tomography (AET)
Atomic level resolution in 3D electron tomography reconstructions has been demonstrated. Reconstructions of crystal defects such as stacking faults, grain boundaries, dislocations, and twinning in structures have been achieved. This method is relevant to the physical sciences, where cryo-EM techniques cannot always be used to locate the coordinates of individual atoms in disordered materials. AET reconstructions are achieved using the combination of an ADF-STEM tomographic tilt series and iterative algorithms for reconstruction. Currently, algorithms such as the real-space algebraic reconstruction technique (ART) and the fast fourier transform equal slope tomography (EST) are used to address issues such as image noise, sample drift, and limited data. AET has been used to find the 3D coordinates of 3,769 atoms in a tungsten needle with 19 pm precision and 20,000 atoms in a multiply twinned palladium nanoparticle. The combination of AET with electron energy loss spectroscopy (EELS) allows for investigation of electronic states in addition to 3D reconstruction. Challenges to atomic level resolution from electron tomography include the need for better reconstruction algorithms and increased precision of tilt angle required to image defects in non-crystalline samples.

Different tilting methods
Standard single-tilt sample holders have a limited rotation of ±80°, leading to a missing wedge in the reconstruction. Another solution is to use needle shaped-samples to allow for full rotation.