TEM optical stability benchmark
[Preview of the PantaRhei user interface showing input astigmatism data over time on the left side and a model-based evaluation on the right side.]
Through the introduction of hardware aberration correctors the achievable resolution in high-resolution transmission electron microscopy (HRTEM) has been pushed down into the sub-Ångström regime. With this development, also the required precision level to measure and adjust the optical properties of transmission electron microscopes has become increasingly demanding. Instabilities of the optical parameters over time represent thus a severe limitation of the achievable accuracy and precision in the material structure analysis. The optical stability is an intrumental property, which is of similar fundamental importance as the achievable spatial resolution.
PantaRhei is a software for the automated evaluation of optical stability tests for transmission electron microscopes. This tool allows you to
- benchmark the optical stability, i.e. the usability of your microscope in standard and long-time experiments, based on a lifetime and on probability figures,
- track the optical stability of your microscope over years,
- compare the optical stability of different microscopes, and
- visualize the evolution of optical imaging parameters with time.
PantaRhei comprises a graphical user interface for the direct visualization of data and evaluation results as shown below. The program runs under Microsoft Windows XP/7/8 operating systems.
The optical stability benchmark is based on a simple standard experiment in high-resolution transmission electron microscopy (HRTEM). It requires a prior aquisition of a series of TEM images and a measurement of the twofold astigmatism from each of the images. The resulting list of astigmatism values is loaded from a log file of the astigmatism measurement including timestamps. The temporal evolution of the measured astigmatism can be displayed and processed in a step-by-step procedure yielding estimates of the lifetime of the optical state in numerical and graphical form.