Quantitative X-ray microanalysis of a mouse cardiac muscle by means of the freeze substitution method

Author(s):  
Vinci Mizuhira ◽  
Michiko Shiihashi

"Analytical electron microscope": We have deviced a new analytical electron microscope in Japan for the detection of elemental localization in tissues and cells in 1973.Our analytical EM is basically composed of a JEM 100C transmission electron microscope fitted with a scanning device(ASID-4), a side-entry goniometer stage and an energy dispersive type X-ray microanalyzer unit(EDAX-707B) with an EDIT-Computer system.Freeze substitution method: We compared the results between the freeze dried and the freeze substituted sections of fresh mouse kidney before the cardiac muscle examination. The results were clear that the freeze substitution method with ether or acetone followed by vinylcyclohexane dioxide (ERL-4206) resin mixture seems superior both in the STEM-image and the X-ray microanalysis to that of the freeze dried method.Freshly prepared mouse heart muscle was cut in small pieces within a 3 mm3 in size, mounted on an alminum foil, and frozen with cooled methycyclohexane at the liquid nitrogen temperature, after acrolein vapor fixation for 3 min.

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.


2001 ◽  
Vol 7 (S2) ◽  
pp. 694-695
Author(s):  
Eric Lifshin ◽  
Raynald Gauvin ◽  
Di Wu

In Castaing’s classic Ph.D. dissertation he described how the limiting value of x-ray spatial resolution for x-ray microanalysis, of about 1 μm, was not imposed by the diameter of the electron beam, but by the size of the region excited inside the specimen. Fifty years later this limit still applies to the majority of measurement made in EMAs and SEMs, even though there is often a need to analyze much finer structures. When high resolution chemical analysis is required, it is generally necessary to prepare thin sections and examine them in an analytical electron microscope where the maximum diameter of the excited volume may be as small as a few nanometers. Since it is not always possible or practical, it is important to determine just what is the best spatial resolution attainable for the examination of polished or “as received” samples with an EMA or SEM and how to achieve it experimentally.


2014 ◽  
Vol 20 (4) ◽  
pp. 1318-1326 ◽  
Author(s):  
Nestor J. Zaluzec

AbstractClosed form analytical equations used to calculate the collection solid angle of six common geometries of solid-state X-ray detectors in scanning and scanning/transmission analytical electron microscopy are presented. Using these formulae one can make realistic comparisons of the merits of the different detector geometries in modern electron column instruments. This work updates earlier formulations and adds new detector configurations.


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