The absorption factor of any material for X-rays is a simple combination of the (tabulated or calculated) contributions of the individual atom types, based on mass density. The values are highly dependent on the incident wavelength.

A useful site is: http://henke.lbl.gov/optical_constants/atten2.html

The absorption factor of any material for X-rays is a simple combination of the (tabulated or calculated) contributions of the individual atom types, based on mass density. The values are highly dependent on the incident wavelength.

A useful site is: http://henke.lbl.gov/optical_constants/atten2.html

Dear Mustafa.

This question is very well covered in the book, LI Mirkin 'Handbook of X-Ray analysis of Polycrystalline Materials". Here is a very simple formula for the calculation of both linear and mass absorption coefficients in the compounds by using different wavelengths. Here you will find a lot of useful things.

http://scripts.iucr.org/cgi-bin/paper?a04822

The mass absorption coefficients of elements can be found in any X-ray text books. For an alloy, if you know the density of your material, a simple rules of mixture can be used to calculate mass absorption coefficient based on the elements of the alloy, which is multiplied with density gives the linear absorption coefficient. This is an indirect way to estimate if the experiment can not be done.

How do I use this information to calculate penetration depth in materials (reflection mode)? Mono-crystals and Poly-crystals.

Example: GaSb & InAs/InAsSb

Symmetric (004) reflection.

I think the answer is above. I see lots of links. I'm working on it. A little slow though!

I could use some help. Thanks!

μ_(m = ∑_i▒〖C_i [ 〖(μ_m ) 〗_(i,λ0).cscφ +〗 (μ_m )_(i,λj).cscѰ])

(µm) = mass absorption coefficient of entire specimen

(µm)i = mass absorption coefficient of elements i

Ci = mass fraction of the different matrix element

λ0= wavelength of primary radiation

λj = wavelength of analyte line

ψ= take of angle of the fluorescence radiation

φ= incident angle of primary radiation

This formula used to calculate mass absorption coefficient of material for x-ray

If this formula is not clear i can send you same in word.

You can see the attached file here.

Linear absorption coefficient is calculated by formula .

U=(u/p)1p1+(u/p)2p2+....

Dear all: These answers are in general correct when the alloy phase concentrations and the sample density are knew; otherwise you could determine the lineal absorption coefficient by an experimental way putting a flat thin uniform layer of your sample over a polycrystalline sample of a well diffracting phase (several intense peaks) Then you must to measure the intensity of the substrate peaks before and after deposition of the layer, and the linear absorption coefficient is calculated by the formula: µ= - (sin theta)*ln(I/Io)/(2d) where theta is the diffraction angle, Io is the intensity of the peak without layer, I is the intensity with layer, and d is the width of the layer.

Priceless information Carlos! " the linear absorption coefficient is calculated by the formula: µ= - (sin theta)*ln(I/Io)/(2d) where theta is the diffraction angle, Io is the intensity of the peak without layer, I is the intensity with layer, and d is the width of the layer."

Please post a reference when convenient. Thanks!

Mass absortion coeffient , µ, determination method used:

Exemple: Pt (NH3)2 Cl2

Cu radiation

µ = d Sum(i) P(i) [µ(i) / ]

d, g/cm3 = density = 3.86

µ(i) /  = mass absorption coefficients of each element for the used lambda (International Tables for X-Ray Crystallography, Volume III, pages 162-165)

Element Atomic weight % fractional µ(i) /  P.µ(i) / 

Pt x 1 195.09 0.65 200.0 130.000

N x 2 28.014 0.09 7.52 0.70

Cl x 2 70.906 0.24 106.0 25.01

H x 6 6.048 0.02 0.435 0.01

_______

155.72

µ = 3.86 x 155.72 = 601.02 cm-1

Even "dunder heads" like me can follow that José! Thanks! :-)

I'll look up the tables for GaAs and InAsSb and try your approach. How would I accomplish this for the MBE super lattice epi of InAsSb/InAs with 25nm period and 10 periods amounting to about 0.5um epi film on GaSb (001) substrate?

Veer! Will the relationship you display work in the case of XRD as well besides XRF? Specifically, for the reflection mode.

μ_(m = ∑_i▒〖C_i [ 〖(μ_m ) 〗_(i,λ0).cscφ +〗 (μ_m )_(i,λj).cscѰ])

(µm) = mass absorption coefficient of entire specimen (GaAs)

(µm)i = mass absorption coefficient of elements i (Ga, As)

Ci = mass fraction of the different matrix element (GaAs for example 1:1)

λ0= wavelength of primary radiation (monochromatic Cu K Alpha 1)

λj = wavelength of analyte line (monochromatic Cu K Alpha 1)

ψ= take of angle of the fluorescence radiation (symmetric reflection)

φ= incident angle of primary radiation (symmetric reflection)

Dear Ravi;

As phenomenon in both the cases XRD and XRF is similar i.e. interaction of x-ray with matter. so if we can find out the above mentioned parameter one can calculate mass absorption coefficient.

Well Ravi, I posted a conference in my references in which the cited XRD method was used for me a first time. Really I didn't took it from literature, but I simply "created" it. I look for something similar in literature but I don't find anything. Nevertheless I didn't try to publish this method because it seems to me quite evident, but if you need some reference you could use this. In this work the method is employed to determine the width of a membrane, but is the same principle in reversal. Please, if you have some doubt let write it. The tittle is "Producción de membranas de sílice para ultrafiltración" sorry, it is in spanish, but the section where the method is, is not too large.