Modifications Needed for Performing High-Resolution Cryosem in a Hitachi S-4700 Fesem Using an Emitech K1250 Cryo-Preparation System

Abstract

Cryo-techniques have been successfully used in scanning electron microscopy (SEM). They are especially promising for high-resolution SEM to improve specimen preservation and reduce radiation damage [1, 2]. A number of cryo-preparation systems are commercially available for SEM, however, our experience has shown that modifications are needed to perform highresolution imaging (>50,000x).Emitech K1250 system consists of a sample preparation chamber, control unit, and cryo-stage. Magnetron sputter coating is standard and electron-beam evaporation is optional. A vacuum transfer device facilitates the sample transfer between the preparation chamber and the SEM to prevent contamination. The Emitech cryo-stage replaces the Hitachi S-4700 standard stage and the cryo-stage temperature is monitored and controlled by the Emitech control unit.The specimen is mounted on a sample holder that mounts to the cryo-stage. Therefore, the distance from the specimen to cryo-stage, the thermal capacity of the sample holder, and the thermal contact between them will affect the actual temperature of the specimen.