Electron Optic Documents

High resolution structure determination by electron cryo-microscopy (cryoEM) and Single Particle Analysis (SPA) has progressed to the point where structures can be determined routinely to better than 3Å on a 300 kV microscope. Pioneering efforts have shown that similar results can also be achieved on 200 kV platforms. Similarly, efforts are underway to allow for a structure determination within a single day or even less. Here, we show results from Merk et al. at NIH from the JEOL CRYO ARM™ 200 obtained on beta-galactosidase at 1.8Å resolution1. The 3D map shows surprising details in the map reflecting the high resolution quality of the data.

High resolution structure determination by electron cryo-microscopy (cryoEM) and Single Particle Analysis (SPA) has progressed to the point where structures can be determined routinely to better than 2Å on a 300 kV microscope. Here, we show results from Kato et al. at1 Osaka University from the JEOL CRYO ARM™ 300 installed at SPring8 (Riken, Japan), that was obtained on mouse heavy chain apo-ferritin at 1.5Å resolution. The 3D map shows surprising details in the map reflecting the high resolution quality of the data.

Micro electron diffraction, or microED, is a technique aimed at solving structures of biological macromolecules by electron diffraction. Barn-storming work by the group from Prof. Gonen showed the impressive impact and promise of this technique1. The technique borrows from X-ray crystallography in that precession techniques are used for data collection and that much of the well-established software for solving structures by X-ray crystallography can be used for microED. However, it differs in a fundamental way in that electrons are used, which, owing to the substantially larger scattering cross-section of electrons with biological matter, means much smaller crystals can be used.

Scanning electron microscopes (SEM) coupled with an energy dispersive X-ray detector (EDS) are used extensively to provide insight into a sample’s chemical makeup. This SEM-EDS technique can provide information on the elements present, their relative concentrations and spatial distribution over very small volumes (micron and some instances nanometer scale).

In this study, we combined a newly designed windowless EDS and SXES, and tried to establish a simple method to analyze the chemical state of Si negative electrodes in charged states.

The holy grail of nanoscale analysis with EDS is to quickly analyze any features which can be imaged in the SEM. However, for nanoscale features this is complicated by that fact that X-ray spatial resolution is typically larger than SEM imaging resolution. Figure 1 shows EDS maps from an integrated circuit cross section at 15kV and 6kV using a W SEM and an FE SEM, as well as the approximate X-ray signal depths at those voltages.

Biological SEM comparisons and Materials SEM comparisons

The tabletop workflow solutions from JEOL allow researchers to setup a compact and user-friendly lab environment without compromising data integrity. This technology seamlessly guides the user from sample preparation to imaging, microanalysis and reporting.

The JSM-IT200LA SEM delivers the ultimate user experience for high through- put imaging and elemental analysis. An embedded color camera simplifies specimen navigation, advanced automation delivers crisp secondary and backscatter images in seconds, and Real-Time (Live) EDS provides instant feedback of the specimen composition for intuitive operation at any experi- ence level. This All-in-One SEM also includes high and low vacuum modes for observation of a wide range of specimen types without compromise. All of this is delivered at a great value.

CRYO ARM Bibliography