Evolution of X-Ray Instrumentation & Techniques, 1970-1990

1995 ◽  
Vol 39 ◽  
pp. 13-18
Author(s):  
Ron Jenkins

While both X-ray Fluorescence Analysis and X-ray Powder Diffractometry have their roots back in the earlier half of this century it wasn't until the 1960s that the two techniques became widely accepted. The growth in the application of X-ray methods for materials analysis grew rapidly between 1960 and 1970, then gained another major leap forward in the early ‘70s with the introduction of mincomputers. The introduction of Si(Li) detectors in the late’ 60s and early ‘70s added a further dimension to the available instrumentation. This paper reviews the growth in the field of X-ray materials analysis and highlights the major mile-stones in intrumentation and techniques.

1975 ◽  
Vol 29 (6) ◽  
pp. 481-485 ◽  
Author(s):  
Donald L. McAlpin ◽  
Charles T. Kenner

A method of x-ray fluorescence analysis for high antimonial lead alloys has been developed to cover antimony concentrations between 6 and 18%, a range not covered in previously published x-ray methods. The proposed method utilizes a General Electric XRD 6 VS spectrometer, chill-cast mold, and a special cutting bit to produce a smooth surface. Ten separate 10-sec counts are taken at 120° intervals to offset nonhomogeneity of the surface. Average counts vs concentration are plotted to obtain calibration curves and percentage concentration. The precision and accuracy of the proposed method compare favorably with the classical wet method. The average standard deviation of the proposed method in terms of the amount present is 1.19% for antimony, 2.03% for tin, and 2.37% for arsenic. These values are within the limits required in the specifications of most high antimonial lead alloys. A time saving of 2 h per sample is realized by the x-ray method over the classical wet method.


2014 ◽  
Vol 1656 ◽  
pp. 123-136
Author(s):  
Blythe McCarthy ◽  
Pamela Vandiver ◽  
Alexander Nagel ◽  
Laure Dussubieux

ABSTRACTOur knowledge of glass production in ancient Egypt has been well augmented not only by the publication of recently excavated materials and glass workshops, but also by more recent materials analysis, and experiments of modern glass-makers attempting to reconstruct the production process of thin-walled core-formed glass vessels. The small but well preserved glass collection of the Freer Gallery of Art in Washington, D.C. was used to examine and study the technology and production of ancient Egyptian core-formed glass vessels. Previous study suggests that most of these vessels were produced in the 18th Dynasty in the 15th and 14th centuries BCE, while others date from the Hellenistic period and later. In an ongoing project we conducted computed radiography, x-ray fluorescence analysis and scanning electron microscopy on a selected group of vessels to understand further aspects of the ancient production process. This paper will provide an overview of our recent research.


Author(s):  
D. A. Carpenter ◽  
M. A. Taylor

The development of intense sources of x rays has led to renewed interest in the use of microbeams of x rays in x-ray fluorescence analysis. Sparks pointed out that the use of x rays as a probe offered the advantages of high sensitivity, low detection limits, low beam damage, and large penetration depths with minimal specimen preparation or perturbation. In addition, the option of air operation provided special advantages for examination of hydrated systems or for nondestructive microanalysis of large specimens.The disadvantages of synchrotron sources prompted the development of laboratory-based instrumentation with various schemes to maximize the beam flux while maintaining small point-to-point resolution. Nichols and Ryon developed a microprobe using a rotating anode source and a modified microdiffractometer. Cross and Wherry showed that by close-coupling the x-ray source, specimen, and detector, good intensities could be obtained for beam sizes between 30 and 100μm. More importantly, both groups combined specimen scanning with modern imaging techniques for rapid element mapping.


Author(s):  
Richard B. Mott ◽  
John J. Friel ◽  
Charles G. Waldman

X-rays are emitted from a relatively large volume in bulk samples, limiting the smallest features which are visible in X-ray maps. Beam spreading also hampers attempts to make geometric measurements of features based on their boundaries in X-ray maps. This has prompted recent interest in using low voltages, and consequently mapping L or M lines, in order to minimize the blurring of the maps.An alternative strategy draws on the extensive work in image restoration (deblurring) developed in space science and astronomy since the 1960s. A recent example is the restoration of images from the Hubble Space Telescope prior to its new optics. Extensive literature exists on the theory of image restoration. The simplest case and its correspondence with X-ray mapping parameters is shown in Figures 1 and 2.Using pixels much smaller than the X-ray volume, a small object of differing composition from the matrix generates a broad, low response. This shape corresponds to the point spread function (PSF). The observed X-ray map can be modeled as an “ideal” map, with an X-ray volume of zero, convolved with the PSF. Figure 2a shows the 1-dimensional case of a line profile across a thin layer. Figure 2b shows an idealized noise-free profile which is then convolved with the PSF to give the blurred profile of Figure 2c.


Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.


2020 ◽  
Vol 86 (10) ◽  
pp. 5-9
Author(s):  
D. G. Filatova ◽  
A. A. Arkhipenko ◽  
M. A. Statkus ◽  
V. V. Es’kina ◽  
V. B. Baranovskaya ◽  
...  

An approach to sorptive separation of Se (IV) from solutions on a novel S,N-containing sorbent with subsequent determination of the analyte in the sorbent phase by micro-x-ray fluorescence method is presented. The sorbent copolymethylenesulfide-N-alkyl-methylenamine (CMA) was synthesized using «snake in the cage» procedure and proven to be stable in acid solutions. Conditions for quantitative extraction of Se (IV) were determined: sorption in 5 M HCl or 0.05 M HNO3 solutions when heated to 60°C, phase contact time being 1 h. The residual selenium content in the solution was determined by inductively coupled plasma mass spectrometry (ICP-MS) using 82Se isotope. The absence of selenium losses is proved and the mechanism of sorption interaction under specified conditions is proposed. The method of micro-x-ray fluorescence analysis (micro-RFA) with mapping revealed a uniform distribution of selenium on the sorbent surface. The possibility of determining selenium in the sorbent phase by micro-RFA is shown. When comparing the obtained results with the results of calculations by the method of fundamental parameters, it is shown the necessity of using standard samples of sorbates to obtain correct results of RFA determination of selenium in the sorbent phase.


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