Dear Wedad A. Alwesabi ,

the relation of the x-ray attenuation cross section sigma with respect to the transmission T of a sample is given by:

T = I/Io = exp(-sigma*n*d)*) with n = the number density (i.e. the number of particles per unit volume of sample) of the attenuating particles**), and d the path length in the sample. This exponential equation is similar to the Lambert-Beer law.

However, in your case, I would like to suggest, to use the NIST/XCOM database***), which will directly deliver the energy dependence of the x-ray mass-attenuation coefficient (µ/rho) for the whole compound (here ZnO-TiO). You only have to acquire the mean density rhoZnO-TiO of the ZnO-TiO in your sample (i.e. the amount of ZnO-TiO per volume):

T = exp(-(µ/rho)ZnO-TiO * rhoZnO-TiO *d)

Both formulae are equivalent...

Please do not forget to consider the x-ray attenuation contribution of the host matrix of your sample...

*) see for example the section 'Attenuation of a beam of particles' in:

https://en.wikipedia.org/wiki/Cross_section_(physics)

and https://en.wikipedia.org/wiki/Absorption_cross_section

**) for example the compound 'ZnO-TiO' is here regarded as a particle being equivalent a 'molecule' TiZnO2. The attenuation cross section is calculated via your formula given in your attachment of your recent question:

https://www.researchgate.net/post/I_synthesized_TiO2-ZnO_nanocomposites_with_different_concentrations_My_question_about_molar_mass_of_this_composition

***) https://physics.nist.gov/PhysRefData/Xcom/html/xcom1.html

The calculation of the weighted sums of (µ/rho) for a compound, as it is presented in the attachment of **), is already done here...

Good luck and

best regards

G.M.