A TEM phase plate loading system with loading monitoring and nano-positioning functions

We present a phase plate loading system developed for a commercial transmission electron microscope (TEM). Our system can be installed without modifying the optical design of the TEM. This system is equipped with a loading monitoring set that allows users to easily and safely locate the phase plate between the pole pieces, and also comes with an airlock that permits quick loading of a phase plate without the need to re-vent the TEM column. The system uses a home-made three-axis nano-positioner to precisely position the phase plate hole at the desired location. Our system has a precision of ∼10 nm, an improvement of one order of magnitude compared with the precision of a phase plate holder modified from an objective aperture. We demonstrate the successful installation and the use of the loading system to place a phase plate at the desired position. Our phase plate loading system can be used to accommodate various types of phase plates and thus provides a good way to greatly speed up the development of TEM phase plates.