The wavelet transform for pre-processing IR spectra in the identification of mono- and di-substituted benzenes

This paper describes the wavelet transformation of IR spectra with the Daubechies analysing wavelet functions as a feature extracting method that successfully reduces the spectral data more than 20-fold with a significant improvement in the classification process

Constraints, iteration schemes and convergence criteria for concentration calculations in X-ray fluorescence spectrometry with the use of fundamental parameter methods

A set of computer programs for X-ray fluorescence calculations, based on fundamental parameter methods, was developed in which some new combinations of mathematical refinement procedures were tested together with new target functions and iteration stop criteria. The results show that practical needs cannot be fulfilled with a single-universal method and a strategy is given to deal with the following situations: (1) not all elements present in the sample have been measured; (2) the mass thickness of the sample is not known and/or has to be determined together with the composition of the sample; and (3) the only unmeasured element is oxygen. If the optimal method is chosen, the results for the major constituents are accurate to better than 1%. For minor constituents, the accuracy is generally of the order of a few percent

The influence of scattering processes in quantitative X-ray fluorescence analysis

Existing theory was used to develop a fundamental parameter (FP) computer program for quantitative X-ray fluorescence (XRF) spectrometry in which scattering interactions are taken into account. The program is suited for polychromatic radiation and composite samples and is used to estimate the errors that result from neglecting the scattering contributions in the analysis of samples in a low Z matrix when the spectrometer is calibrated either on pure elements or on standards similar to the samples

Determination of diffusion profiles of silver ions in soda-lime–silica glass by X-ray fluorescence spectrometry

A nondestructive method based on X-ray fluorescence (XRF) spectrometry is presented for the determination of concentration-depth profiles in the top layer of flat solid samples. The method was tested in the determination of the interdiffusion coefficient of silver and sodium ions in soda-lime–silica glass. Calculations are based on semi-infinite diffusion with constant boundary concentration of the silver ion. The diffusion coefficient found at 633 K for penetration times between 300 and 3600 s ranged between 1.1×10−10 and 1.6×10−10 cm2 s−1

Non-destructive analysis of small irregularly shaped homogenous samples by X-ray fluorescence spectrometry

A new calibration procedure is proposed for the non-destructive analysis of small sized samples of irregular shape by X-ray fluorescence spectrometry. The calibration is performed using normal calibration standards and measurements. The calculations for the calibration and the analysis of unknown samples are based on small modifications of existing procedures and software. The method was tested on fused bead samples as well as on pressed powder samples.\ud \ud The possibility to perform quantitative analysis on this type of samples is obtained at the cost of some accuracy. A relative root mean square error of 1.5% averaged over all elements tested was found in the new calibration procedure for the fused bead samples, versus 1.4% using the normal calibration procedure. For most elements the accuracy deteriorates somewhat except for sodium and magnesium.\ud \ud For the pressed powder samples the relative root mean square errors of the normal and newly proposed calibration method are comparable (average 3%), except for sodium, where there is an improvement from 15 to 7%

Applicability of X-ray fluorescence spectroscopy as method to determine thickness and composition of stacks of metal thin films: A comparison with imaging and profilometry

In this work the applicability of X-ray fluorescence spectroscopy (XRF) for fast, accurate and non-destructive determination of the thickness of a variety of single-layer and multi-layer metal thin films deposited on glass and silicon is investigated. Data obtained with XRF is compared with information from profilometry and images from scanning electron microscopy (SEM). Whereas thickness determinations based on profilometry and cross-sectional SEM-imaging have restrictions with respect to thickness of metal stacks or hardness of the metals, XRF has no such limitations. Moreover, XRF can discriminate between sublayers in a multi-layer film, and can also be utilized for compositional analysis and density estimations. Good agreement between thickness data obtained with XRF, profilometry and SEM-images is found, under the justifiable assumption that the density of sputter-deposited and evaporated thin films is ca. 5% below that of bulk metals. Similar XRF-results are found for non-patterned areas (64 mm2 metal) as well as lithographically patterned areas containing a series of small metal lines (total metal surface ca. 8 mm2). As a consequence, it is concluded that XRF is a versatile technique for analysis, verification, control or evaluation of the thickness, density or (elemental) composition of thin metal film line-patterns, during their fabrication as well as prior or post to applications

Applicability of X-ray fluorescence spectroscopy as method to determine thickness and composition of stacks of metal thin films: A comparison with imaging and profilometry

In this work the applicability of X-ray fluorescence spectroscopy (XRF) for fast, accurate and non-destructive determination of the thickness of a variety of single-layer and multi-layer metal thin films deposited on glass and silicon is investigated. Data obtained with XRF is compared with information from profilometry and images from scanning electron microscopy (SEM). Whereas thickness determinations based on profilometry and cross-sectional SEM-imaging have restrictions with respect to thickness of metal stacks or hardness of the metals, XRF has no such limitations. Moreover, XRF can discriminate between sublayers in a multi-layer film, and can also be utilized for compositional analysis and density estimations. Good agreement between thickness data obtained with XRF, profilometry and SEM-images is found, under the justifiable assumption that the density of sputter-deposited and evaporated thin films is ca. 5% below that of bulk metals. Similar XRF-results are found for non-patterned areas (64 mm2 metal) as well as lithographically patterned areas containing a series of small metal lines (total metal surface ca. 8 mm2). As a consequence, it is concluded that XRF is a versatile technique for analysis, verification, control or evaluation of the thickness, density or (elemental) composition of thin metal film line-patterns, during their fabrication as well as prior or post to applications