Details of STEM

Craven, A. J.

doi:10.1002/9781119978848.ch6

Cited by 1 publication

(1 citation statement)

References 19 publications

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“…Conversely, as Δ E decreases, the beam current is further attenuated, reducing the number of electrons. Therefore for high levels of beam attenuation, this results in a lower SNR which decreases at a rate of the square root of the number of electrons due to the increasing effect of Poisson noise (Craven, 2011). The curves for the two lower Schottky FEG C c coefficients in Figure 4a follow the same trend except that their SNR peaks are shifted to higher electron energy spreads as their lower C c coefficients mean chromatic aberration will have less of an effect on their SNR.…”

Section: Resultsmentioning

confidence: 99%

Cost and Capability Compromises in STEM Instrumentation for Low-Voltage Imaging

Quigley

McBean

O′Donovan

et al. 2022

Microscopy and Microanalysis

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Low-voltage transmission electron microscopy (≤80 kV) has many applications in imaging beam-sensitive samples, such as metallic nanoparticles, which may become damaged at higher voltages. To improve resolution, spherical aberration can be corrected for in a scanning transmission electron microscope (STEM); however, chromatic aberration may then dominate, limiting the ultimate resolution of the microscope. Using image simulations, we examine how a chromatic aberration corrector, different objective lenses, and different beam energy spreads each affect the image quality of a gold nanoparticle imaged at low voltages in a spherical aberration-corrected STEM. A quantitative analysis of the simulated examples can inform the choice of instrumentation for low-voltage imaging. We here demonstrate a methodology whereby the optimum energy spread to operate a specific STEM can be deduced. This methodology can then be adapted to the specific sample and instrument of the reader, enabling them to make an informed economical choice as to what would be most beneficial for their STEM in the cost-conscious landscape of scientific infrastructure.

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Section: Resultsmentioning

confidence: 99%