Ultrahigh-Vacuum Third-Order Spherical Aberration (Cs) Corrector for a Scanning Transmission Electron Microscope

2006 ◽  
Vol 12 (6) ◽  
pp. 456-460 ◽  
Author(s):  
Kazutaka Mitsuishi ◽  
Masaki Takeguchi ◽  
Yukihito Kondo ◽  
Fumio Hosokawa ◽  
Kimiharu Okamoto ◽  
...  
Keyword(s):  
Materials Science ◽  
Spherical Aberration ◽  
Ultrahigh Vacuum ◽  
Scanning Transmission Electron Microscope ◽  
Third Order ◽  
Scanning Transmission Electron ◽  
Spot Area ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Fifth Order

Initial results from an ultrahigh-vacuum (UHV) third-order spherical aberration (Cs) corrector for a dedicated scanning transmission electron microscopy, installed at the National Institute for Materials Science, Tsukuba, Japan, are presented here. The Cs corrector is of the dual hexapole type. It is UHV compatible and was installed on a UHV column. The Ronchigram obtained showed an extension of the sweet spot area, indicating a successful correction of the third-order spherical aberration Cs. The power spectrum of an image demonstrated that the resolution achieved was 0.1 nm. A first trial of the direct measurement of the fifth-order spherical aberration C5 was also attempted on the basis of a Ronchigram fringe measurement.

Tuning Fifth-Order Aberrations in a Quadrupole-Octupole Corrector

2012 ◽  
Vol 18 (4) ◽  
pp. 699-704 ◽  
Author(s):  
Andrew R. Lupini ◽  
Stephen J. Pennycook
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Spherical Aberration ◽  
Scanning Transmission Electron Microscope ◽  
Low Energy ◽  
Third Order ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Microscopes ◽  
Fifth Order

AbstractThe resolution of conventional electron microscopes is usually limited by spherical aberration. Microscopes equipped with aberration correctors are then primarily limited by higher order, chromatic, and misalignment aberrations. In particular the Nion third-order aberration correctors installed on machines with a low energy spread and possessing sophisticated alignment software were limited by the uncorrected fifth-order aberrations. Here we show how the Nion fifth-order aberration corrector can be used to adjust and reduce some of the fourth- and fifth-order aberrations in a probe-corrected scanning transmission electron microscope.

Resolution in the Scanning Transmission Electron Microscope

1972 ◽  
Vol 30 ◽  
pp. 454-455
Author(s):  
M. G. R. Thomson
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Spherical Aberration ◽  
Signal To Noise Ratio ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Objective Lens ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The variation of contrast and signal to noise ratio with change in detector solid angle in the high resolution scanning transmission electron microscope was discussed in an earlier paper. In that paper the conclusions were that the most favourable conditions for the imaging of isolated single heavy atoms were, using the notation in figure 1, either bright field phase contrast with β0⋍0.5 α0, or dark field with an annular detector subtending an angle between ao and effectively π/2.The microscope is represented simply by the model illustrated in figure 1, and the objective lens is characterised by its coefficient of spherical aberration Cs. All the results for the Scanning Transmission Electron Microscope (STEM) may with care be applied to the Conventional Electron Microscope (CEM). The object atom is represented as detailed in reference 2, except that ϕ(θ) is taken to be the constant ϕ(0) to simplify the integration. This is reasonable for θ ≤ 0.1 θ0, where 60 is the screening angle.

A Quantitative Nanodiffraction System for Ultrahigh Vacuum Scanning Transmission Electron Microscopy

2003 ◽  
Vol 9 (5) ◽  
pp. 468-474 ◽  
Author(s):  
Gary G. Hembree ◽  
Christoph Koch ◽  
John C.H. Spence
Keyword(s):  
Electron Microscope ◽  
Dynamic Range ◽  
Spherical Aberration ◽  
Ultrahigh Vacuum ◽  
Objective Lens ◽  
Specimen Preparation ◽  
Modulation Transfer ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

Of all the long-lived particles available as probes of condensed matter, and of all the signals available on a modern electron microscope, electron nanodiffraction patterns provide the strongest signal from the smallest volume. The technique is therefore perfectly suited to nanostructural investigations in inorganic chemistry and materials science. The Vacuum Generators HB501S, an ultrahigh vacuum (UHV) variant of the HB501 scanning transmission electron microscope (STEM), with side-entry double-tilt stage, specimen preparation and analysis chamber, three postspecimen lenses, and cold field-emission tip with integral magnetic gun lens, has therefore been modified to optimize nanodiffraction and quantitative convergent beam electron diffraction (QCBED) performance. A one-micrometer grain-size phosphor screen lying on a fiber-optic faceplate atop the instrument is fiber-optically coupled to a 2048 × 2048 charge-coupled device (CCD), 16-bit camera. This arrangement promises to provide much greater sensitivity, larger dynamic range, and a better modulation transfer function (MTF) than conventional single crystal scintillator (YAG) CCD systems, with noticeable absence of cross talk between pixels. The design of the nanodiffraction detector system is discussed, the gain of the detector is measured, the spherical aberration constant of the objective lens is measured by the Ronchigram method, and preliminary results from the modified instrument are shown.

Attainment of 40.5 pm spatial resolution using 300 kV scanning transmission electron microscope equipped with fifth-order aberration corrector

Microscopy ◽  
2017 ◽  
Vol 67 (1) ◽  
pp. 46-50
Author(s):  
Shigeyuki Morishita ◽  
Ryo Ishikawa ◽  
Yuji Kohno ◽  
Hidetaka Sawada ◽  
Naoya Shibata ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Spatial Resolution ◽  
Transmission Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Technological Developments ◽  
Resolution Imaging ◽  
Fifth Order

Abstract The achievement of a fine electron probe for high-resolution imaging in scanning transmission electron microscopy requires technological developments, especially in electron optics. For this purpose, we developed a microscope with a fifth-order aberration corrector that operates at 300 kV. The contrast flat region in an experimental Ronchigram, which indicates the aberration-free angle, was expanded to 70 mrad. By using a probe with convergence angle of 40 mrad in the scanning transmission electron microscope at 300 kV, we attained the spatial resolution of 40.5 pm, which is the projected interatomic distance between Ga–Ga atomic columns of GaN observed along [212] direction.

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