Role of HVEM for in situ studies in materials science: The microlaboratory

1991 ◽  
Vol 49 ◽  
pp. 470-471
Author(s):  
Charles W. Allen ◽  
Kenneth H. Westmacotp
Keyword(s):  
High Resolution ◽  
Materials Science ◽  
Bulk Material ◽  
High Energy ◽  
Objective Lens ◽  
High Resolution Imaging ◽  
Working Space ◽  
Experimental Apparatus ◽  
Resolution Imaging

With the development of the Atomic Resolution Microscope (JEOL ARM-1000) about a decade ago and the current availability of new ultra high resolution HVEMs, the important role of HVEM in high resolution imaging has been well achieved. Higher spatial resolution imaging is attainable with higher energy electrons without sacrificing sample tilting capability by virtue of a smaller CSλ value. When commercial HVEMs first became available in the mid 1960's, however, it was not the prospect of high resolution imaging which seemed most important but rather the fact that, for a given material, significantly thicker specimens could be examined.The microstructures (ultrastructures) and physical behavior of these foils (up to 15 μm thick) would be more representative of those for the bulk material. And especially for materials science applications two other factors were also of paramount importance: (1) the controlled generation of vacancy-interstitial (Frenkel) pairs in crystalline pure elements and alloys by high energy electron irradiation became possible and (2) the increased working space in the objective lens region allowed some miniaturized experimental apparatus to be incorporated.

High resolution imaging with high energy ion beams

1993 ◽  
Vol 77 (1-4) ◽  
pp. 153-168 ◽  
Author(s):  
G.J.F. Legge ◽  
J.S. Laird ◽  
L.M. Mason ◽  
A. Saint ◽  
M. Cholewa ◽  
...  
Keyword(s):  
High Resolution ◽  
High Energy ◽  
Ion Beams ◽  
High Resolution Imaging ◽  
Resolution Imaging

scholarly journals Linking morphology with activity through the lifetime of pretreated PtNi nanostructured thin film catalysts

2015 ◽  
Vol 3 (21) ◽  
pp. 11660-11667 ◽  
Author(s):  
D. A. Cullen ◽  
M. Lopez-Haro ◽  
P. Bayle-Guillemaud ◽  
L. Guetaz ◽  
M. K. Debe ◽  
...  
Keyword(s):  
Thin Film ◽  
High Resolution ◽  
Electron Tomography ◽  
Critical Role ◽  
High Resolution Imaging ◽  
Nanostructured Thin Film ◽  
Highly Active ◽  
Thin Film Catalysts ◽  
Resolution Imaging

High resolution imaging and electron tomography are used to link nanoscale morphology with electrochemical activity in highly active Pt3Ni7nanostructured thin film catalysts, revealing the critical role of catalyst conditioning.

Fulfilling the needs of physical and biological scientists in intermediate and HVEM

1991 ◽  
Vol 49 ◽  
pp. 424-425
Author(s):  
Michael M. Kersker
Keyword(s):  
Cross Section ◽  
High Voltage ◽  
Ionization Cross Section ◽  
Materials Science ◽  
Objective Lens ◽  
High Resolution Imaging ◽  
Irradiation Effects ◽  
Ionization Cross ◽  
The Past ◽  
Resolution Imaging

There are three (therefore 4 or 5) reasons that high voltage microscopes have remained viable tools for applications in both biological and materials science. Higher voltage means higher penetration with lessened effect from image degrading mechanisms, higher resolution due to decreased electron wavelength, and more (or less) damage to structure due to irradiation effects (more) or to decreased ionization cross section (less). Of the 47 high voltage instruments (V > 500kV) installed worldwide, many remain operational for at least one of these three reasons.Few existing instruments are capable of delivering all three advantages. Earlier microscopes were primarily focussed on providing increased penetration and more or less damage since the high voltage stability and objective lens designs were not optimized to provide high resolution imaging as well. Though the past requirements for fulfilling the needs of physical and biological scientists have not changed for now nor are they likely to change in the future, many of the requirements fulfilled by high voltage microscopes are now achievable using lower kV intermediate voltage instruments, and in some cases, even more ubiquitous lower kV ones.

scholarly journals The role of high-resolution imaging in the evaluation of nanosystems for bioactive encapsulation and targeted nanotherapy

Micron ◽  
2007 ◽  
Vol 38 (8) ◽  
pp. 804-818 ◽  
Author(s):  
Kianoush Khosravi-Darani ◽  
Abbas Pardakhty ◽  
Hamid Honarpisheh ◽  
V.S.N. Malleswara Rao ◽  
M. Reza Mozafari
Keyword(s):  
High Resolution ◽  
High Resolution Imaging ◽  
Resolution Imaging

High-Resolution Imaging with an Aberration-Corrected Transmission Electron Micrscope

2001 ◽  
Vol 7 (S2) ◽  
pp. 904-905
Author(s):  
M. Lentzen ◽  
B. Jahnen ◽  
C.L. Jia ◽  
K. Urban
Keyword(s):  
High Resolution ◽  
Phase Contrast ◽  
Spherical Aberration ◽  
Spatial Coherence ◽  
Objective Lens ◽  
Pass Band ◽  
High Resolution Imaging ◽  
Resolution Imaging ◽  
High Level ◽  
Correction System

In electron microscopy high-resolution imaging of finest object structures is generally hampered by the influence of aberrations of the lens system, especially the high spherical aberration of the objective lens. The delocalization of contrast details induced by aberrations is especially strong for microscopes equipped with a field emission gun providing a high spatial coherence. in recent years a prototype of an aberration correction system has been constructed by Haider et al., following a suggestion by Rose, consisting of two hexapole elements and four additional round lenses. The correction system was adapted to a Philips CM 200 FEG ST microscope with an information limit of 0.13 nm. The alignment is carried out using aberration measurements deduced from Zemlin tableaus. By appropriately exciting the hexapole elements it is possible to reduce or even fully compensate the spherical aberration of the objective lens.With the freedom of a variable spherical aberration Cs new operation modes can be accessed that are not available in standard microscopes. with Cs = 0 and defocus Z = 0 pure amplitude contrast occurs, together with a vanishing contrast delocalization; phase contrast with a single, narrow pass-band up to the information limit can still be achieved by Z = ±7 nm, which introduces a delocalization of R = 0.13 nm. with Cs = 97 μm and Z = −18 nm the broad Scherzer pass-band for phase contrast can be extended to the information limit, with R = 0.35 nm. For the CM 200 Cs = 43 fim and Z = −12 nm still produces a high level of phase contrast, comparable with the extended Scherzer pass-band, but with R = 0.08 nm only. in the latter mode Scherzer’s defocus equals Lichte's defocus of least confusion.

A CMOS-based large-area high-resolution imaging system for high-energy x-ray applications

2008 ◽  
Author(s):  
Brian Rodricks ◽  
Boyd Fowler ◽  
Chiao Liu ◽  
John Lowes ◽  
Dean Haeffner ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging System ◽  
High Energy ◽  
High Resolution Imaging ◽  
Large Area ◽  
X Ray ◽  
Resolution Imaging

A ring coded‐aperture microscope for high‐resolution imaging of high‐energy x rays

1992 ◽  
Vol 63 (10) ◽  
pp. 5086-5088 ◽  
Author(s):  
D. Ress ◽  
D. R. Ciarlo ◽  
J. E. Stewart ◽  
P. M. Bell ◽  
D. R. Kania
Keyword(s):  
High Resolution ◽  
High Energy ◽  
Coded Aperture ◽  
High Resolution Imaging ◽  
X Rays ◽  
Resolution Imaging

An Ultra-High-Resolution Objective Lens for a 200-kV TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 132-133
Author(s):  
J.G. Bakker ◽  
P.E.S. Asselbergs
Keyword(s):  
High Resolution ◽  
Structural Information ◽  
Spherical Aberration ◽  
Atomic Scale ◽  
Objective Lens ◽  
High Resolution Imaging ◽  
X Ray ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Resolution Imaging

High resolution TEM imaging has been well established as superb technique for obtaining structural information about materials on an atomic scale. Trends in equipment for high resolution imaging have progressed to the stage where point resolutions below 2 Å can be obtained at 200 kV. This paper describes such a new objective lens for the Philips CM20 Transmission Electron Microscope.In designing a new objective lens, several parameters have to be taken into account. Not only should the coefficient of spherical aberration of the objective lens be minimised, the lens should also allow considerable tilting of the specimen in two directions. The lens should be compatible with X-ray analysis. And last but not least, the design of lens must ensure that the heat transfer of the lens to the specimen environment is minimised.

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