Absorption tomography

The projection p(s, 6) is the line integral of n x, y) along the LOS, defined by s and 9, times the absorption cross-section cr at the laser source line freqnency n T are the limits of integration. It can be related to the initial (1°) and transmitted (7 ) laser-beam intensities as shown. 

Because the reconstruction problem is ill-posed, the solution or reconstruction method must be tuned to the problem at hand as defined by the character of n x,y) and the number and distribution over s and 9 of the available projections p si,9j). 

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INFRARED ABSORPTION TOMOGRAPHY FOR ACTIVE COMBUSTION CONTROL... 

A substantial extension to the penetration depth of Raman spectroscopy was accomplished utilizing the properties of diffuse light in analogy with NIR absorption tomography [3-5] or fluorescence spectroscopy [6-9]. This chapter reviews recent developments in this area and illustrates the utility of these methods on several practical examples. 

Optical Coherence Tomography and Optical Coherence Microscopy to Monitor Water Absorption... 

Table 5.2 Summary of selected analytical methods for molecular environmental geochemistry. AAS Atomic absorption spectroscopy AFM Atomic force microscopy (also known as SFM) CT Computerized tomography EDS Energy dispersive spectrometry. EELS Electron energy loss spectroscopy EM Electron microscopy EPR Electron paramagnetic resonance (also known as ESR) ESR Electron spin resonance (also known as EPR) EXAFS Extended X-ray absorption fine structure FUR Fourier transform infrared FIR-TEM Fligh-resolution transmission electron microscopy ICP-AES Inductively-coupled plasma atomic emission spectrometry ICP-MS Inductively-coupled plasma mass spectrometry. Reproduced by permission of American Geophysical Union. O Day PA (1999) Molecular environmental geochemistry. Rev Geophysics 37 249-274. Copyright 1999 American Geophysical Union...

XAS XMCD XPCS XPS XTM X-ray Absorption Spectroscopy X-ray Magnetic Circular Dichroism X-ray Photon Correlation Spectroscopy X-ray Photoemission Spectroscopy X-ray Tomography... 

The mathematical reconstruction of a property field, F(x,y), from its projection in the 0 direction is the basis of "Computerized Tomography" (1,2). An identical technique can be used to reconstruct a field of linear absorption coefficient functions in a combusting flow field from multiangular path integrated absorption measurements. The linear absorption coefficient is the familiar N.Q. product, where is the concentration of species i and Q. is the absorption cross section of species i at the frequency v. The Bouguer-Lambert-Beer law states that... 

For soft human tissue that would be otherwise have too low a contrast to be resolved in conventional high-intensity planar X-ray radiography, a thorough study of X-ray absorbance as a function of tissue density and thickness allowed the development of hardware and software for computed axial tomography (CAT scanning) which performs a three-dimensional analysis of X-ray absorption at low intensities and convenient two-dimensional displays of resolved human tissue features. 

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