Development and application of a computer control system for an analytical electron microscope

1990 ◽  
Vol 1 (9) ◽  
pp. 887-893 ◽  
Author(s):  
R Schneider ◽  
W Rechner ◽  
A Pippel ◽  
J Bischoff
Author(s):  
C. W. Mehard ◽  
W. L. Epstein

The underlying cause of a disease may not he readily apparent but may have a long history in development. We report one such case which was diagnosed with the aid of the analytical electron microscope.The patient, a 48 yr. old white female, developed a tender nodule on the sole of her foot in December, 1981. Subsequently additional lesions developed on the same foot resulting in deep pain and tenderness. Superficial lesions also extended up to the knee on both legs. No abnormalities were revealed in blood tests or chest X-rays.


Author(s):  
N. Ridley ◽  
S.A. Al-Salman ◽  
G.W. Lorimer

The application of the technique of analytical electron microscopy to the study of partitioning of Mn (1) and Cr (2) during the austenite-pearlite transformation in eutectoid steels has been described in previous papers. In both of these investigations, ‘in-situ’ analyses of individual cementite and ferrite plates in thin foils showed that the alloying elements partitioned preferentially to cementite at the transformation front at higher reaction temperatures. At lower temperatures partitioning did not occur and it was possible to identify a ‘no-partition’ temperature for each of the steels examined.In the present work partitioning during the pearlite transformation has been studied in a eutectoid steel containing 1.95 wt% Si. Measurements of pearlite interlamellar spacings showed, however, that except at the highest reaction temperatures the spacing would be too small to make the in-situ analysis of individual cementite plates possible, without interference from adjacent ferrite lamellae. The minimum diameter of the analysis probe on the instrument used, an EMMA-4 analytical electron microscope, was approximately 100 nm.


Author(s):  
Zenji Horita ◽  
Ryuzo Nishimachi ◽  
Takeshi Sano ◽  
Minoru Nemoto

Absorption correction is often required in quantitative x-ray microanalysis of thin specimens using the analytical electron microscope. For such correction, it is convenient to use the extrapolation method[l] because the thickness, density and mass absorption coefficient are not necessary in the method. The characteristic x-ray intensities measured for the analysis are only requirement for the absorption correction. However, to achieve extrapolation, it is imperative to obtain data points more than two at different thicknesses in the identical composition. Thus, the method encounters difficulty in analyzing a region equivalent to beam size or the specimen with uniform thickness. The purpose of this study is to modify the method so that extrapolation becomes feasible in such limited conditions. Applicability of the new form is examined by using a standard sample and then it is applied to quantification of phases in a Ni-Al-W ternary alloy.The earlier equation for the extrapolation method was formulated based on the facts that the magnitude of x-ray absorption increases with increasing thickness and that the intensity of a characteristic x-ray exhibiting negligible absorption in the specimen is used as a measure of thickness.


Author(s):  
S. M. Zemyan ◽  
D. B. Williams

As has been reported elsewhere, a thin evaporated Cr film can be used to monitor the x-ray peak to background ratio (P/B) in an analytical electron microscope. Presented here are the results of P/B measurements for the Cr Ka line on a Philips EM430 TEM/STEM, with Link Si(Li) and intrinsic Ge (IG) x-ray detectors. The goal of the study was to determine the best conditions for x-ray microanalysis.We used the Fiori P/B definition, in which P/B is the ratio of the total peak integral to the average background in a 10 eV channel beneath the peak. Peak and background integrals were determined by the window method, using a peak window from 5.0 to 5.7 keV about Cr Kα, and background windows from 4.1 to 4.8 keV and 6.3 to 7.0 keV.


Author(s):  
Vinayak P. Dravid ◽  
H. Zhang ◽  
L.D. Marks ◽  
J.P. Zhang

A 200 kV cold field emission gun atomic resolution analytical electron microscope (ARAEM, Hitachi HF-2000) has been recently installed at Northwestern. The ARAEM offers an unprecedented combination of atomic structure imaging of better than 0.20 nm nominal point-to-point resolution and about 0.10 nm line resolution, alongwith nanoscale analytical capabilities and electron holography in one single instrument. The ARAEM has been fully functional/operational and this paper presents some illustrative examples of application of ARAEM techniques to oxide superconductors. Additional results will be presented at the meeting.


Author(s):  
T. Kaneyama ◽  
M. Naruse ◽  
Y. Ishida ◽  
M. Kersker

In the field of materials science, the importance of the ultrahigh resolution analytical electron microscope (UHRAEM) is increasing. A new UHRAEM which provides a resolution of better than 0.2 nm and allows analysis of a few nm areas has been developed. [Fig. 1 shows the external view] The followings are some characteristic features of the UHRAEM.Objective lens (OL)Two types of OL polepieces (URP for ±10' specimen tilt and ARP for ±30' tilt) have been developed. The optical constants shown in the table on the next page are figures calculated by the finite element method. However, Cs was experimentally confirmed by two methods (namely, Beam Tilt method and Krivanek method) as 0.45 ∼ 0.50 mm for URP and as 0.9 ∼ 1.0 mm for ARP, respectively. Fig. 2 shows an optical diffractogram obtained from a micrograph of amorphous carbon with URP under the Scherzer defocus condition. It demonstrates a resolution of 0.19 nm and a Cs smaller than 0.5 mm.


Author(s):  
K. Fukushima ◽  
T. Kaneyama ◽  
F. Hosokawa ◽  
H. Tsuno ◽  
T. Honda ◽  
...  

Recently, in the materials science field, the ultrahigh resolution analytical electron microscope (UHRAEM) has become a very important instrument to study extremely fine areas of the specimen. The requirements related to the performance of the UHRAEM are becoming gradually severer. Some basic characteristic features required of an objective lens are as follows, and the practical performance of the UHRAEM should be judged by totally evaluating them.1) Ultrahigh resolution to resolve ultrafine structure by atomic-level observation.2) Nanometer probe analysis to analyse the constituent elements in nm-areas of the specimen.3) Better performance of x-ray detection for EDS analysis, that is, higher take-off angle and larger detection solid angle.4) Higher specimen tilting angle to adjust the specimen orientation.To attain these requirements simultaneously, the objective lens polepiece must have smaller spherical and chromatic aberration coefficients and must keep enough open space around the specimen holder in it.


2011 ◽  
Vol 19 (3) ◽  
pp. 72-72
Author(s):  
Graham Cliff

I write this as a materials scientist concerned about the inadequacy of regulation, monitoring, and control of what are known as nanoparticles (NPs). This is not because present particulate legislation is “inadequate” but because it is inadequately policed and does NOT extend to small enough particulates. I have analyzed these very small particles in the analytical electron microscope (AEM) for over thirty-seven years. A graduate student, with whom I worked over thirty years ago, described in her thesis the conclusion that these particles would have “long-range environmental impact.” We did not then have the benefit of hindsight.


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