IT-4-P-6138 airSTEM: high resolution STEM detection in open air

airSEM™ is an innovative scanning electron microscope which sidesteps the main obstacles stemming from the need for vacuum as a prerequisite for capture of high-resolution images.
The technology overcomes fundamental electron beam imaging related challenges, such as scattering of electrons by gas molecules and efficient signal collection, leading to a resolution better than 5nm under ambient conditions.
The airSEM™ represents a new approach to electron microcopy, enabling to image objects close to their natural state and simplifying the integration of multiple imaging techniques on a single imaging platform.
Having STEM detection capability in open air addresses several challenges associated with vacuum STEM: a. Imaging samples which are not vacuum compatible in particular hydrated samples. b. Cross correlating data from different modalities which are commonly situated on different platforms. In addition operating in air simplifies operation and significantly reduces the time for data acquisition.
This study focuses on the characterization of STEM performance in airSEM™, in particular measuring the scattering angle of transmitted electron in air. The angles were measured for two SiN membranes of different thickness and at different distances separating the scattering membrane and the detector.
The data shows that mass thickness contrast is preserved despite the scattering of electrons by the air molecules. Images of biological cross sections, organic and inorganic particles taken with airSTEM detector both in bright field and dark field modes are shown.