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A material's half-value layer (HVL), or half-value thickness, is the thickness of the material at which the intensity of radiation entering it is reduced by one half. [1] HVL can also be expressed in terms of air kerma rate (AKR), rather than intensity: the half-value layer is the thickness of specified material that, "attenuates the beam of radiation to an extent such that the AKR is reduced ...
The half-value layer (HVL) is the thickness of a layer of material required to reduce the radiant flux of the transmitted radiation to half its incident magnitude. The half-value layer is about 69% (ln 2) of the penetration depth. Engineers use these equations predict how much shielding thickness is required to attenuate radiation to acceptable ...
A 1951 USAF resolution test chart is a microscopic optical resolution test device originally defined by the U.S. Air Force MIL-STD-150A standard of 1951. The design provides numerous small target shapes exhibiting a stepped assortment of precise spatial frequency specimens.
The test was pivotal in understanding the fracture problems of ships during World War II. [2] [3] The test was developed around 1900 by S. B. Russell (1898, American) and Georges Charpy (1901, French). [4] The test became known as the Charpy test in the early 1900s due to the technical contributions and standardization efforts by Charpy.
Full width at half maximum. In a distribution, full width at half maximum (FWHM) is the difference between the two values of the independent variable at which the dependent variable is equal to half of its maximum value. In other words, it is the width of a spectrum curve measured between those points on the y-axis which are half the maximum ...
Mass attenuation coefficients of selected elements for X-ray photons with energies up to 250 keV. The mass attenuation coefficient, or mass narrow beam attenuation coefficient of a material is the attenuation coefficient normalized by the density of the material; that is, the attenuation per unit mass (rather than per unit of distance).
The first ultrasonic thickness gauge was made in 1967 by Werner Sobek; [citation needed] a Polish engineer from Katowice. This first ultrasonic thickness gauge measured the velocity of the waves it emitted in particular test samples, it then calculated the thickness in micrometers from this speed measurement by an applied mathematical equation.
The shape factor has a typical value of about 0.9, but varies with the actual shape of the crystallite; λ {\displaystyle \lambda } is the X-ray wavelength ; β {\displaystyle \beta } is the line broadening at half the maximum intensity ( FWHM ), after subtracting the instrumental line broadening, in radians .