Wavelength spectrometry

Wavelength Spectrometry (WDS) is based upon the phenomenon of Bragg diffraction of X rays incident on a crystal. The difiraction phenomenon is described by the expression ... 

Inductively Coupled and Microwave Induced Plasma Sources for Mass Spectrometry 4 Industrial Analysis with Vibrational Spectroscopy 5 Ionization Methods in Organic Mass Spectrometry 6 Quantitative Millimetre Wavelength Spectrometry 7 Glow Discharge Optical Emission Spectroscopy A Practical Guide 8 Chemometrics in Analytical Spectroscopy, 2nd Edition 9 Raman Spectroscopy in Archaeology and Art History 10 Basic Chemometric Techniques in Atomic Spectroscopy... 

Alder, John F., John G. Baker, and Royal Society of Chemistry (Great Britain). Quantitative Millimetre Wavelength Spectrometry. RSC Analytical Spectroscopy Monographs. Cambridge, U.K. Royal Society of Chemistry, 2002. 

J. F. Aldera, J. G. Baker, Quantitative millimetre wavelength spectrometry. Part IV. Response curves for oxygen in carbon dioxide and nitrogen at 60 GHz, Anal. Chim. Acta., 367,245-253 (1998). 

Quantitative Millimetre Wavelength Spectrometry, by John F. Alder, UMIST, Manchester. UK and John G. Baker, University of Manchester, UK... 

Significance of the Peak Absorption Coefficient Functions for Quantitative Millimetre Wavelength Spectrometry... 

What is then the purpose to quantitative millimetre wavelength spectrometry, and when will be its season ... 

There is then a purpose for MMW spectrometry within the array of modem analytical methods. Through the efforts of the scientists and engineers over 60 years who have provided us with such a wealth of knowledge and diversity of components, all the ingredients are there to develop this powerful technique. Now is the season for Quantitative Millimetre Wavelength Spectrometry to grow into the elegant maturity that befits it. 

Quantitative Millimetre Wavelength Spectrometry will be welcomed by practitioners in both industry and academia. 

One of the most difficult areas in which to find suitable diffracting crystals is that of long (> 20A) wavelength spectrometry. Several alternatives to single crystals... 

The method of dual-wavelength spectrometry was already proposed by Chance in 1951 [37] Giese and French [6] constructed a double-beam dual-wavelength spectrophotometer for this purpose. But the merits of developing it were not pointed out until 1969 and later by Shibata et al. [38-41]. 

Photoacoustic spectrometry (pas) differs from the other methods in that the detector is a microphone. This makes pas wavelength independent. 

Fig. 4. Examples of emission spectrometry as a diagnostic monitoring tool for plasma processing, (a) The removal of chlorine contamination from copper diode leads using a hydrogen—nitrogen plasma. Emissions are added together from several wavelengths, (b) The etching and eventual removal of a 50-p.m thick polyimide layer from an aluminum substrate, where (x ) and (° ) correspond to wavelengths (519.82 and 561.02 nm, respectively) for molecular CO2...

X-ray fluorescence spectrometry is a technique for measuring the elemental composition of samples. The basis of the technique is the relationship between the wavelength or energy of the emitted incoherently scattered x-ray photons and the atomic number of the element. This relationship estabHshed in 1913 is... 

These samples were measured non-destructively by energy-dispersive XRF with synclirotron radiation excitation (SYXRS), by g-XRF, by wavelength-dispersive XRF (WDXRS), and by Rutherford back scattering (RBS), by X-ray reflectometry (XRR) and by destructive secondary ion mass spectrometry (SIMS) as well (both last methods were used for independant comparison). 

The electron-optical performance of the EPMA system is indistinguishable from that of a conventional scanning electron microscope (SEM) thus, EPMA combines all of the imaging capabilities of a SEM with quantitative elemental analysis using both energy- and wavelength-dispersive X-ray spectrometry. ... 

The analyst has two practical means of measuring the energy distribution of X rays emitted from the specimen energy-dispersive spectrometry and wavelength dispersive spectrometry. These two spectrometers are highly complementary the strengths of each compensate for the weaknesses of the other, and a well-equipped electron probe instrument will have both spectrometers. 

Raman spectrometry is another variant which has become important. To quote one expert (Purcell 1993), In 1928, the Indian physicist C.V. Raman (later the first Indian Nobel prizewinner) reported the discovery of frequency-shifted lines in the scattered light of transparent substances. The shifted lines, Raman announced, were independent of the exciting radiation and characteristic of the sample itself. It appears that Raman was motivated by a passion to understand the deep blue colour of the Mediterranean. The many uses of this technique include examination of polymers and of silicon for microcircuits (using an exciting wavelength to which silicon is transparent). 

FCC feedstocks contain sulfur in the form of organic-sulfur compounds such as mercaptan, sulfide, and thiophenes. Frequently, as the residue content of crude oil increases, so does the sulfur content (Table 2-5). Total sulfur in FCC feed is determined by the wavelength dispersive x-ray fluorescence spectrometry method (ASTM D-2622), The results are expressed as elemental sulfur. 

---