MAXRD SYMBOL

AttenuationCoefficient

AttenuationCoefficient[crystal]
returns the linear attenuation coefficient for crystal.

AttenuationCoefficient[crystal,λ]
returns the linear attenuation coefficient for crystal at wavelength λ.

Details and OptionsDetails and Options

  • The wavelength λ may be be omitted if it is contained in the crystal entry in $CrystalData. One may also use an energy quantity instead of wavelength, as the input is passed through InputCheck. In either case, input may be a number or a Quantity.
  • The following interaction phenomena are considered in the contribution to the overall attenuation of the X-ray beam. The columns denote name of the phenomena, alternative names and short descriptions, respectively.
  • Photoelectric scattering (σpe)photoionisationabsorbed photon results in ejected electron
    Coherent scattering (σcoh)Rayleigh-, Thompson-, classical- or elastic scatteringscattering off bound electrons
    Incoherent scattering (σincoh)Compton- or inelastic scatteringphoton energy results in ejected electron as well as scattered photon with less energy
  • Other effects, such as pair production and photo-disintegration, are not taken into account.
  • Options from GetScatteringCrossSections:
  • "PhysicalProcess"""select one type of scattering cross section to consider
    "Source""xraylib"source of cross section or data
    "Units"Trueoutput as a Quantity with units
  • Options exclusive to this function:
  • "Coefficient""LinearAttenuation"type of coefficient to calculate
    "MassCoefficientMethod""DivideByDensity"whether to use atomic mass formula or divide by
  • The following settings are supported for the "Coefficient" option. is Avogadro's constant, the atomic weight and the total cross section [1, p. 213]:
  • "LinearAttenuation"μσtot=σpe+σcoh+σincoh
    "MassAbsorption"μ/ρ
  • The following settings are supported for the "MassCoefficientMethod":
  • "DivideByDensity"calculate then divide by
  • If the name of the input source is contained both in the directory for the atomic scattering factors and the cross sections, the data from the cross sections will be used.
    The imaginary part of the atomic scattering factor () can be used to calculate the photoelectric scattering cross section () with the following relation [2]:
    • Click for copyable input

ExamplesExamplesopen allclose all

Basic Examples  (2)Basic Examples  (2)

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If "Units" is set to False, the returned number has units of reciprocal centimeters:

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Options  (4)Options  (4)

Possible Issues  (1)Possible Issues  (1)

Mathematica code  (1)Mathematica code  (1)

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