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Homework Help: X-Ray Diffraction HWK Problems

  1. Feb 25, 2009 #1
    1. The problem statement, all variables and given/known data
    1. The intensities of Kalpha and Kbeta of a Cu X-ray tube have a ratio of about 10/1. It is desirable to increase the ratio to 1000/1 by using a Ni foil as a critical absorber. What should be the thickness of the Ni foil? How much attenuation in intensity has the Cu Kalpha suffered?

    2. Suppose FeAl (i.e. Fe50Al50) exists in two forms: ordered phase and disordered phase. In the ordered phase, Fe and Al form two interpenetrating sc sublattices. Each al atom is surrounded by 8 Fe atoms at the eight corners of a cube, and vice versa. In the disordered phase, Fe and Al randomly occupy the 8 corners and the body center of a cube. What would be x-ray diffraction patterns for the two phases?

    2. Relevant equations
    1. I = Ioexp[u*x] = Ioexp[(u/rho)*rho*x]
    where I = attenuation of a photon intensity through a material.
    u = absorption coefficient (in cm^-1) and (1/u) = one absorption length.
    rho = density of the material (usually it is not u but u/rho (in units of cm^2/g that is tabulated.
    1 barn = 10^-24 cm^2

    2. Have no clue!

    3. The attempt at a solution

    1. I have no clue how to even do this. I can't find any equations relating the filter thickness to the information given. Any help is greatly appreciated! I only know we are supposed to use the attenuation equation for the second part of question 1. Thanks in Advance!

    2. I also have no clue how do this! Please help! Thanks in Advance!
  2. jcsd
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