The relation between latitude and solar-cycle variations in the neutron-monitor mass-absorption coefficient

1968 ◽  
Vol 46 (10) ◽  
pp. S1087-S1089 ◽  
Author(s):  
Miriam A. Forman
Keyword(s):  
Solar Cycle ◽  
Absorption Coefficient ◽  
Sea Level ◽  
Neutron Monitor ◽  
Mass Absorption Coefficient ◽  
Cutoff Rigidity ◽  
Neutron Monitors ◽  
Solar Cycle Variation ◽  
Mass Absorption ◽  
Pressure Altitude

The differential mass-absorption coefficient for rigidities between 2 and 15 GeV/c for IGY-type neutron monitors at sea level and at 500 mm Hg pressure altitude has been calculated from the variation of the neutron-monitor intensity and mass-absorption coefficient with cutoff rigidity. Combined with six sea-level surveys of neutron-monitor intensity between 1954 and 1962, and assuming no time variation in the neutron-monitor mass-absorption coefficient above 15 GeV/c cutoff, the calculated differential mass-absorption coefficient implies a solar-cycle variation of about 0.04%/mm Hg at 2 GeV/c cutoff rigidity at sea level.

Simultaneous Determination of Layer Thickness, Composition, and Mass Absorption by X-Ray Diffraction

1992 ◽  
Vol 7 (4) ◽  
pp. 194-196 ◽  
Author(s):  
Stefano Battaglia ◽  
Marco Franzini ◽  
Leonardo Leoni
Keyword(s):  
Absorption Coefficient ◽  
Simultaneous Determination ◽  
Mass Absorption Coefficient ◽  
Crystalline Substance ◽  
X Ray Diffraction ◽  
Mass Thickness ◽  
Mass Absorption ◽  
Crystalline Substrate ◽  
Quantitative Results

AbstractThis paper describes a new method for the simultaneous determination of mineral composition, mass thickness and mass absorption coefficient of a thin layer of a crystalline substance deposited on a crystalline substrate.The samples were deposited on membrane disc filters, consisting of mixtures of cellulose acetate and cellulose nitrate. Quantitative results are achieved by measuring the diffraction intensity of the analyte and the attenuation of a reflection of the crystalline material supporting the deposited sample. The mean accuracy of the analysis was found to be: ≈ 3% for mass thickness, ≈ 1% for mass absorption coefficient and ≈ 4% for quantitative mineralogical determination.

Mass Absorption Coefficient Measurements Using Thin Films

1969 ◽  
Vol 13 ◽  
pp. 632-638 ◽  
Author(s):  
P. Lublin ◽  
P. Cukor ◽  
R. J. Jaworowski
Keyword(s):  
Thin Films ◽  
Absorption Coefficient ◽  
Mass Absorption Coefficient ◽  
Absorption Coefficients ◽  
Electron Probe Analysis ◽  
Mass Absorption ◽  
Probe Analysis ◽  
Absorption Correction ◽  
Thin Foils ◽  
Metal Organic

For quantitative electron probe analysis, the raw intensity ratios must be corrected to take into account deviations due to absorption, fluoresecnce and electron beam penetration. The major correction is usually the absorption correction, so that for best results, accurate mass absorption coefficients are required. Many tables of absorption coefficients are calculated by interpolation or extrapolation from available measured values, and therefore new measurements are required for increased reliability. The region which requires the most attention for present-day probe analysis is the 2 to 10 Å range.Thin foils of the lighter metals are available for mass absorption coefficient measurements, but heavy metal foils, which must be extremely thin, are not obtainable, A method has been developed to prepare thin films of heavy metals on a suitable substrate by pyrolytic decomposition of metal organic compounds.

Measurement of Mass Absorption Coefficients Using Compton-Scattered Cu Radiation in X-ray Diffraction Analysis

1990 ◽  
Vol 34 ◽  
pp. 325-335 ◽  
Author(s):  
Steve J. Chipera ◽  
David L. Bish
Keyword(s):  
Chemical Composition ◽  
Solid State ◽  
Absorption Coefficient ◽  
Mass Absorption Coefficient ◽  
X Rays ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
Solid State Detector ◽  
X Ray ◽  
Mass Absorption

AbstractThe mass absorption coefficient is a useful parameter for quantitative characterization of materials. If the chemical composition of a sample is known, the mass absorption coefficient can be calculated directly. However, the mass absorption coefficient must be determined empirically if the chemical composition is unknown. Traditional methods for determining the mass absorption coefficient involve measuring the transmission of monochromatic X-rays through a sample of known thickness and density. Reynolds (1963,1967), however, proposed a method for determining the mass absorption coefficient by measuring the Compton or inelastic X-ray scattering from a sample using Mo radiation on an X-ray fluorescence spectrometer (XRF). With the recent advances in solid-state detectors/electronics for use with conventional powder diffractometers, it is now possible to readily determine mass absorption coefficients during routine X-ray diffraction (XRD) analyses.Using Cu Kα radiation and Reynolds’ method on a Siemens D-500 diffractometer fitted with a Kevex Si(Li) solid-state detector, we have measured the mass absorption coefficients of a suite of minerals and pure chemical compounds ranging in μ/ρ from graphite to Fe-metal (μ/ρ = 4.6-308 using Cu Kα radiation) to ±4.0% (lσ). The relationship between the known mass absorption coefficient and the inverse count rate is linear with a correlation coefficient of 0.997. Using mass absorption coefficients, phase abundances can be determined during quantitative XRD analysis without requiring the use of an internal standard, even when an amorphous component is present.

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