Mass attenuation coefficient - Revision history

MassimoNespolo: lang

2018-05-08T15:14:06Z

lang

BrianMcMahon: Added German and Spanish translations (U. Mueller)

2017-11-16T12:38:49Z

Added German and Spanish translations (U. Mueller)

BrianMcMahon at 09:13, 20 May 2017

2017-05-20T09:13:43Z

BrianMcMahon at 09:11, 20 May 2017

2017-05-20T09:11:58Z

BrianMcMahon: Style edits to align with printed edition

2017-05-20T09:11:26Z

Style edits to align with printed edition

BrianMcMahon: Created page with "== Definition == The mass attenuation coefficient in cm²/g can be written as a sum of separated photoelectric mass absorption coefficients $[\mu/\rho]_{PE}$
2016-04-13T10:21:55Z

Created page with "== Definition == The mass attenuation coefficient in cm2/g can be written as a sum of separated photoelectric mass absorption coefficients <math>[\mu/\rho]_{PE}</..."

New page
== Definition ==

The mass attenuation coefficient in cm2/g can be written as a sum of separated photoelectric mass [[absorption coefficient]]s <math>[\mu/\rho]_{PE}</math> and coherent <math>[\sigma/\rho]_{coh}</math> and incoherent <math>[\sigma/\rho]_{incoh}</math> scattering contributions:

<math>[\mu/\rho]_{TOT}=[\mu/\rho]_{PE} +[\sigma/\rho]_{coh} +[\sigma/\rho]_{incoh}</math>

or equivalently

<math>[\mu/\rho]_{TOT}=[\mu/\rho]_{PE} +[\mu/\rho]_{coh} +[\mu/\rho]_{incoh}.</math>

It is recommended that <math>[\mu/\rho]_{TOT}</math> be used to distinguish this from the mass [[absorption coefficient]] <math>[\mu/\rho]_{PE}</math> (''q.v.'') as they are both commonly presented as <math>[\mu/\rho]</math>.

The last two contributions are angle-dependent. Note that while absorptive processes are linear (''see'' [[absorption coefficient]]), coherent scattering (and incoherent scattering) are not linear and hence the attenuation coefficient does not obey the Beer-Lambert Law.

The mass attenuation coefficient is conventionally given by the symbol <math>[\mu/\rho] = \sigma/(uA)</math>, where <math>\sigma</math> is the cross-section in barns/atom (1 barn = <math>10^{-24}</math> cm2), <math>u</math> is the atomic mass unit, and <math>A</math> is the relative atomic mass of the target element (''i.e''. in amu; the mass relative to 12 for carbon 12).

Where a material is composed of separate layers, the total ''absorption'' is given by the sum

<math>\ln\Big({I\over{I_0}}\Big)\Big|_{pe} = -\sum_i \Big[{\mu\over\rho}\Big]_{pe,i}[\rho t]_i.</math>

Sometimes mass fractions are used as an approximation for a mixture, assuming that each atomic scatterer is independent.

== See also ==

[[Absorption coefficient]]
[[Cross-section]]
*[[Linear attenuation coefficient]]

[[Category:X-ray absorption spectroscopy]]

← Older revision		Revision as of 15:14, 8 May 2018
Line 1:		Line 1:
−	<font color="red">Massenschwächungskoeffizient</font> (''Ge''). <font color="green">Coeficiente másico de atenuación</font> (''Sp'').	+	<font color="blue">Coefficient massique d'atténuation</font> (''Fr''). <font color="red">Massenschwächungskoeffizient</font> (''Ge''). <font color="black">Coefficiente di attenuazione di massa</font> (''It''). <font color="purple">質量減衰係数</font> (''Ja''). <font color="green">Coeficiente másico de atenuación</font> (''Sp'').

	== Definition ==		== Definition ==

← Older revision		Revision as of 12:38, 16 November 2017
Line 1:		Line 1:
		+	<font color="red">Massenschwächungskoeffizient</font> (''Ge''). <font color="green">Coeficiente másico de atenuación</font> (''Sp'').
		+
	== Definition ==		== Definition ==

@@ Line 1: / Line 1: @@
 == Definition ==
-The mass attenuation coefficient in cm<sup>2</sup> g<sup>&minu;1</sup> can be written as a sum of separated photoelectric mass [[absorption coefficient]]s <math>[\mu/\rho]_{PE}</math> and coherent <math>[\sigma/\rho]_{coh}</math> and incoherent <math>[\sigma/\rho]_{incoh}</math> scattering contributions:
+The mass attenuation coefficient in cm<sup>2</sup> g<sup>&minus;1</sup> can be written as a sum of separated photoelectric mass [[absorption coefficient]]s <math>[\mu/\rho]_{PE}</math> and coherent <math>[\sigma/\rho]_{coh}</math> and incoherent <math>[\sigma/\rho]_{incoh}</math> scattering contributions:
 <math>[\mu/\rho]_{TOT}=[\mu/\rho]_{PE} +[\sigma/\rho]_{coh} +[\sigma/\rho]_{incoh}</math>

@@ Line 1: / Line 1: @@
 == Definition ==
-The mass attenuation coefficient in cm<sup>2</sup>/g can be written as a sum of separated photoelectric mass [[absorption coefficient]]s <math>[\mu/\rho]_{PE}</math> and coherent <math>[\sigma/\rho]_{coh}</math> and incoherent <math>[\sigma/\rho]_{incoh}</math> scattering contributions:
+The mass attenuation coefficient in cm<sup>2</sup> g<sup>&minu;1</sup> can be written as a sum of separated photoelectric mass [[absorption coefficient]]s <math>[\mu/\rho]_{PE}</math> and coherent <math>[\sigma/\rho]_{coh}</math> and incoherent <math>[\sigma/\rho]_{incoh}</math> scattering contributions:
 <math>[\mu/\rho]_{TOT}=[\mu/\rho]_{PE} +[\sigma/\rho]_{coh} +[\sigma/\rho]_{incoh}</math>
@@ Line 11: / Line 11: @@
 It is recommended that <math>[\mu/\rho]_{TOT}</math> be used to distinguish this from the mass [[absorption coefficient]] <math>[\mu/\rho]_{PE}</math> (''q.v.'') as they are both commonly presented as <math>[\mu/\rho]</math>.
-The last two contributions are angle-dependent. Note that while absorptive processes are linear (''see'' [[absorption coefficient]]), coherent scattering (and incoherent scattering) are not linear and hence the attenuation coefficient does not obey the Beer-Lambert Law.
+The last two contributions are angle-dependent. Note that while absorptive processes are linear (see [[absorption coefficient]]), coherent scattering (and incoherent scattering) are not linear and hence the attenuation coefficient does not obey the Beer&ndash;Lambert Law.
-The mass attenuation coefficient is conventionally given by the symbol <math>[\mu/\rho] = \sigma/(uA)</math>, where <math>\sigma</math> is the cross-section in barns/atom (1 barn = <math>10^{-24}</math> cm<sup>2</sup>), <math>u</math> is the atomic mass unit, and <math>A</math> is the relative atomic mass of the target element (''i.e''. in amu; the mass relative to 12 for carbon 12).
+The mass attenuation coefficient is conventionally given by the symbol <math>[\mu/\rho] = \sigma/(uA)</math>, where <math>\sigma</math> is the cross-section in barns/atom (1 barn = <math>10^{-24}</math> cm<sup>2</sup>), <math>u</math> is the atomic mass unit, and <math>A</math> is the relative atomic mass of the target element (''i.e.'' in amu; the mass relative to 12 for carbon 12).
 Where a material is composed of separate layers, the total ''absorption'' is given by the sum

@@ Line 17: / Line 17: @@
 Where a material is composed of separate layers, the total ''absorption'' is given by the sum
-<math>\ln\Big({I\over{I_0}}\Big)\Big|_{pe} = -\sum_i \Big[{\mu\over\rho}\Big]_{pe,i}[\rho t]_i.</math>
+<math>\ln\Big({I\over{I_0}}\Big)\Big|_{PE} = -\sum_i \Big[{\mu\over\rho}\Big]_{PE,i}[\rho t]_i.</math>
 Sometimes mass fractions are used as an approximation for a mixture, assuming that each atomic scatterer is independent.