Development of a 1 MV field-emission transmission electron microscope

Kawasaki, Takeshi; Matsui, Isao; Yoshida, Tetsushi; Katsuta, Teiji; Hayashi, Souichirou; Onai, T.; Furutsu, Tadao; Myochin, K.; Numata, Mitsuhiro; Mogaki, Hiroaki; Gorai, Masahiro; Akashi, Takumi; Kamimura, O.; Matsuda, Tsuyoshi; Osakabe, Nobuyuki; Tonomura, Akira; Kitazawa, Kouichi

doi:10.1093/oxfordjournals.jmicro.a023863

Cited by 36 publications

(11 citation statements)

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“…This pressure is 160 times lower than that of the previous M-FEG for the 1-MV TEM. 7 The preaccelerator magnetic lens has a pole piece with the upper pole diameter of 6 mm and the lower pole diameter of 10 mm. The gap is 6 mm.…”

Section: Methodsmentioning

confidence: 99%

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Magnetic field superimposed cold field emission gun under extreme-high vacuum

Kasuya¹,

Kawasaki²,

Moriya³

et al. 2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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A magnetic-field superimposed cold field emission gun (M-FEG) was developed for a 1.2-MV holography transmission electron microscope (TEM). Differential pumping using three nonevaporative getter pumps reduced the pressure of the gun to an extreme-high vacuum of 3 × 10−10 Pa and provided a stable probe current. The 90% decrease time, at which the current falls to 90% of the initial value, was 900 min. The current variation over the course of 8 h was 5.2%. The superimposed magnetic field provided large probe currents ranging from 1 to 170 nA for total currents ranging from 1 to 300 μA. The reduced pressure caused the angular current density to be twice that of a conventional field emission gun operating at 10−8 Pa. This increase can be explained by the difference between current densities emitted from the clean and adsorbed emitter surfaces. These results show that the developed M-FEG can provide the 1.2-MV TEM with a bright and stable emission current.

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Section: Methodsmentioning

confidence: 99%

“…Another advantage of M-FEGs is the increase in beam current owing to the enlarged acceptance angle by the convergence of electrons. In our previous studies, we installed M-FEG in 350-kV and 1-MV holography TEMs; 6,7 In particular, the 1-MV TEM had brightness of 1.8 Â 10 10 Acm À2 sr À1 .…”

Section: Introductionmentioning

confidence: 99%

Magnetic field superimposed cold field emission gun under extreme-high vacuum

Kasuya¹,

Kawasaki²,

Moriya³

et al. 2014

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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show abstract

“…To solve this inconvenience, hardware, software and sample preparation techniques are presently in development (Koster et al, 1997). Thus, high voltage microscopes (O'Toole et al, 1999), and field emission gun microscopes (Kawasaki et al, 2000) are in expansion. Classification of volumes using neural-network algorithms (Pascual-Montano et al, 2002), as well as the development of new segmentation techniques applied to tomograms (Frangakis and Hegerl, 2002;Volkmann, 2002) increase the resolution and facilitate the interpretation of volumes.…”

Section: Introductionmentioning

confidence: 99%

Use of cryo‐negative staining in tomographic reconstruction of biological objects: application to T4 bacteriophage

Messaoudi

Boudier

Lechaire³

et al. 2003

Biology of the Cell

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Recent advances in electron microscopy and image analysis techniques have resulted in the development of tomography, which makes possible the study of structures neither accessible to X-ray crystallography nor nuclear magnetic resonance. However, the use of tomography to study biological structures, ranging from 100 to 500 nm, requires developments in sample preparation and image analysis. Indeed, cryo-electron tomography present two major drawbacks: the low contrast of recorded images and the sample radiation damage. In the present work we have tested, on T4 bacteriophage samples, the use of a new preparation technique, cryo-negative staining (Adrian et al., 1998), which reduces the radiation damage while preserving a high signal-to-noise ratio (De Carlo et al., 2002). Our results demonstrate that the combination of cryo-negative staining in tomography with standard cryo-microscopy and single particle analysis results in a methodological approach that could be useful in the study of biological structures ranging in the T4 bacteriophage size.

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“…A cm -2 sr -1 [23,24]. The higher voltage allowed thicker specimens to be observed which enhances the contrast seen from vortices.…”

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confidence: 99%

Imaging flux vortices in type II superconductors with a commercial transmission electron microscope

Loudon¹,

Midgley²

2009

Ultramicroscopy

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Flux vortices in superconductors can be imaged using transmission electron microscopy because the electron beam is deflected by the magnetic flux associated with the vortices. This technique has a better spatial and temporal resolution than many other imaging techniques and is sensitive to the magnetic flux density within each vortex, not simply the fields at the sample surface. Despite these advantages, only two groups have successfully employed the technique using specially adapted instruments. Here we demonstrate that vortices can be imaged with a modern, commercial transmission electron microscope operating at 300 kV equipped with a field emission gun, Lorentz lens and a liquid helium cooled sample holder. We introduce superconductivity for non-specialists and discuss techniques for simulating and optimising images of flux vortices. Sample preparation is discussed in detail as the main difficulty with the technique is the requirement for samples with very large (>10µm), flat areas so that the image is not dominated by diffraction contrast. We have imaged vortices in superconducting Bi 2 Sr 2 CaCu 2 O 8-δ and use correlation functions to investigate the ordered arrangements they adopt as a function of applied magnetic field.

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Development of a 1 MV field-emission transmission electron microscope

Cited by 36 publications

References 0 publications

Magnetic field superimposed cold field emission gun under extreme-high vacuum

Magnetic field superimposed cold field emission gun under extreme-high vacuum

Use of cryo‐negative staining in tomographic reconstruction of biological objects: application to T4 bacteriophage

Imaging flux vortices in type II superconductors with a commercial transmission electron microscope

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