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Dedicated STEM for 200 to 40 keV operation

2011; EDP Sciences; Volume: 54; Issue: 3 Linguagem: Inglês

10.1051/epjap/2011100429

1286-0050

Niklas Dellby, Nicholas J. Bacon, P. Hrncirik, Matthew F. Murfitt, Gwyn Skone, Zoltán Szilágyi, Ondrej L. Krivanek,

Electronic and Structural Properties of Oxides

A dedicated STEM developed for operation at primary energies from 200 keV to 40 keV and lower is described. It has a new cold field emission gun (CFEG) that gives a normalized brightness of 3 × 108 A/(m2 sr V), and excellent short-term and long-term stability. It includes two gun lenses (one electrostatic and one electromagnetic), a fast electrostatic beam blanker, three condenser lenses, a corrector of third- and fifth-order geometric aberrations, an objective lens with low aberration coefficients, a flexible set of projector lenses, an ultra-stable sample stage, and provision for storing up to five samples under high vacuum and loading them into the microscope's objective lens under remote control. The microscope is enclosed in a magnetically and acoustically shielding enclosure, which allows it to operate at a high performance level even in non-optimal environments. It has reached 53 pm resolution at 200 keV and 123 pm at 40 keV, and an EELS energy resolution of 0.26 eV.