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Photoacoustic spectroscopy is the measurement of the effect of absorbed electromagnetic energy (particularly of light) on matter by means of acoustic detection. The discovery of the photoacoustic effect dates to 1880 when Alexander Graham Bell showed that thin discs emitted sound when exposed to a beam of sunlight that was rapidly interrupted with a rotating slotted disk.
This inspection is used on partially ferromagnetic materials such as nickel alloys, duplex alloys, and thin-ferromagnetic materials such as ferritic chromium molybdenum stainless steel. The application of a saturation eddy current technique depends on the permeability of the material, tube thickness, and diameter.
Correspondingly, it may be detected by various other means, described by terms such as "photothermal radiometry", [13] "thermal lens" [14] and "thermal beam deflection" (popularly also known as "mirage" effect, see Photothermal spectroscopy). These methods parallel the photoacoustic detection. However, each method has its special range of ...
The amplitude of the pressure wave provides information about the local absorption and propagation of energy in the sample, while the time interval between the illumination pulse and arrival of the ultrasound wave at the detector provides information about the distance between the detector and photoecho source. Optoacoustic data collected over ...
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Acoustic resonance spectroscopy (ARS) is a method of spectroscopy in the acoustic region, primarily the sonic and ultrasonic regions. ARS is typically much more rapid than HPLC and NIR . It is non destructive and requires no sample preparation as the sampling waveguide can simply be pushed into a sample powder/liquid or in contact with a solid ...
When the incident light beam is at Bragg angle, a diffraction pattern emerges where an order of diffracted beam occurs at each angle θ that satisfies: [3] = Here, m = ..., −2, −1, 0, +1, +2, ... is the order of diffraction, λ is the wavelength of light in vacuum, and Λ is the wavelength of the sound. [4]
Mössbauer spectroscopy is a spectroscopic technique based on the Mössbauer effect. This effect, discovered by Rudolf Mössbauer (sometimes written "Moessbauer", German: "Mößbauer") in 1958, consists of the nearly recoil -free emission and absorption of nuclear gamma rays in solids .