INSTRUMENTATION, ELECTRON OPTICS AND X-RAY SPECTROSCOPY

1984 ◽  
Vol 45 (C2) ◽  
pp. C2-149-C2-154 ◽  
Author(s):  
T. Mulvey
Keyword(s):  
1972 ◽  
Vol 16 ◽  
pp. 19-26 ◽  
Author(s):  
R. Wilson ◽  
G. Judd

AbstractElectron optics techniques have been applied to the examination of various evidence materials common to forensic science. Vehicular paint fragments, a common evidence material, possess topographical features suitable for SEM analysis and composition variations in the form of chemically distinct layers and surface contaminant particles which can be characterized using energy dispersive X-ray analysis. The ability to analyze paint samples in terms of both topography and composition presents the potential of an extremely valuable tool for forensic investigators.Over thirty automotive paint samples from many sources were examined in this study, using either the secondary electron image of the SEM or the SEM image combined with concurrent X-ray analysis by an energy dispersive System. Topographical pictures and X-ray spectra were recorded and comparisons between samples were made. Additional characterization of specimens was attempted through the analysis of individual paint layers.The data obtained was used to group the paint samples into categories used for identification of the sample source. This information is valuable to several types of criminal investigation.


2015 ◽  
Vol 65 (2) ◽  
pp. 141-146
Author(s):  
Tae Dong LEE* ◽  
Seong-Ryong RYU ◽  
Yong C. KIM ◽  
In T. HAN
Keyword(s):  

1961 ◽  
Vol 5 ◽  
pp. 527-537
Author(s):  
J. D. Brown ◽  
J. W. Thatcher ◽  
W. J. Campbell

AbstractThe Bureau of Mines purchased the electron optics, vacuum system, and sample stage assembly for the electron-probe X-ray spectrograph and designed and built the two reflection and two transmission scanning curved-crystal spectrometers. The reflection spectrometers were placed in a vacuum chamber for measurements of long-wavelength X-radiation. Operational characteristics of this spectrograph were determined. A low-alloy stainless-steel sample containing 5 wt. % depleted uranium and a stainless-steel sample containing 20 wt. % gadolinium were analyzed.


1997 ◽  
Author(s):  
Gendi Pang ◽  
Randy P. Luhta ◽  
John A. Rowlands

Author(s):  
G. Benner ◽  
R. Bauer ◽  
W. Probst ◽  
E. Weimer ◽  
J.-P. Martin

1. IntroductionIn the materials sciences as well as in the life sciences energy-dispersive x-ray microanalysis (EDX) in the transmission electron microscope (TEM) is now established as a routine investigation method allowing high-sensitivity qualitative and quantitative element detection. The accuracy of the results obtained and the measurement time needed are largely determined by the following properties of the TEM used: shape of the objective lens pole-piece and design of the illumination system, collimation of the beam path and operation flexibility of the illumination system.2. Optimized X-ray detectionIn the EM 910 the design concept of the objective lens allows the x-ray detector to be placed closer to the specimen than usual (Fig. 1). Therefore an extremely high solid angle (i. e. 0.192 sr) of the x-ray signal can be intercepted by a 30 mm2-detector at a take-off angle of 20°. As a result, x-ray spectra can be acquired with a high countrate and a clearly improved signal-to-noise ratio. Element distribution maps with much improved information density can be acquired in the usual registration times.


2001 ◽  
Vol 7 (S2) ◽  
pp. 394-395
Author(s):  
E D Boyes

New analytical methods have been implemented with novel instrumentation designed to extend, to explore and to exploit an expanded performance envelop for high resolution imaging, EDX chemical microanalysis and chemical imaging with robust and representative bulk samples in a scanning electron microscope (SEM). A key contribution is the integrated and innovative design of the in-lens electron optics, sample holders, detectors including for EDX, specimen chamber and vacuum system. Each component has been improved individually over previous practice and they have been made to work together much better, especially with respect to combining advanced electron imaging at low voltages with efficient x-ray analysis and mapping.Compared to a conventional out-of-lens/semi-in-lens FESEM the secondary electron image (SEI) resolution at the widely used low voltage of 1 kV is improved by a factor of almost 2x to <1.5nm and this facilitates low voltage imaging at primary magnifications of 250,000x (Fig.1) or more.


1999 ◽  
Vol 5 (S2) ◽  
pp. 554-555
Author(s):  
C. Conty

The Sepia years. 1951. Castaing’s thesis(1) : Genesis of a Non-Destructive and truly Quantitative Microanalysis method. 1958. The beginning of commercial microprobes : Early instruments had no computers and were lacking special analyzing crystals, but overall they were well designed. Modern features we are familiar with today, such as light element analysis, field emission gun, Energy Dispersive analysis, analysis of insulated material and scanning analysis, although not widely implemented, were discussed in scientific reviews even then(2) 1963. One of my early personal experience: The daring job of obtaining Castaing’s acceptance for his Cameca-buih EPMA at the University of Paris/Orsay.From early models to present microprobes Early microprobes were developed, after WWII, in a world driven by metallurgy. They had few WD spectrometers, usually at low take off angle. However, the need for light element analysis and the fast growing use of EPMA in geology have sent the manufacturers back to the drawing board. Why ? The design of modern microprobes was a compromise between light optics, electron optics and higher take off angle X-ray spectrometry. There were three possible designs of X-ray path geometry : X-rays through the(final) lens, X-rays through the gap of the lens, X-rays outside the lens, hence three suppliers arose based on these concepts.Present and future EPMA improvements. As in the initial era of EPMA newer applications will point the direction in which the electron microprobe of the future should evolve.


Author(s):  
Tae Dong Lee ◽  
Seong-Ryong Ryu ◽  
June Hee Oh ◽  
Han-Sol Park ◽  
Se-Hyun Woo ◽  
...  
Keyword(s):  

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