A simple program for fast tilting electron-beam sensitive crystals to zone axes

Tilting crystals to proper zone axes is a necessary but tedious work in taking selected area electron diffraction patterns (SAED) and high-resolution images using transmission electron microscope (TEM). This process not only costs a lot of time but also limits the application of TEM in electron-beam sensitive materials. Therefore, it is desirable to develop a simple method for tilting crystals from random orientations to a specific zone axis quickly. Herein, we describe a novel program, Zones, which can index the electron diffraction pattern and calculate the tilting angles of a double-tilt sample holder from the current orientation to a desired zone axis. It can also bring crystals that are slightly deviated from a zone axis to the exact zone with the help of Laue ring in the diffraction pattern. This program has been successfully applied to studies of zeolites and metal-organic frameworks (MOFs), known as being electron-beam sensitive. The program shows its power not only in saving the operator's time but also in preventing the crystals from quick beam damages.