p41_043 - 43(a The cut-off wavelength λmin is...

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Unformatted text preview: 43. (a) The cut-off wavelength λmin is characteristic of the incident electrons, not of the target material. This wavelength is the wavelength of a photon with energy equal to the kinetic energy of an incident electron. According to the result of Exercise 3 of Chapter 39, λmin = 1240 eV · nm = 3.54 × 10−2 nm = 35.4 pm . 35 × 103 eV (b) A Kα photon results when an electron in a target atom jumps from the L-shell to the K -shell. The energy of this photon is 25.51 keV − 3.56 keV = 21.95 keV and its wavelength is λKα = (1240 eV · nm)/(21.95 × 103 eV) = 5.65 × 10−2 nm = 56.5 pm. (c) A Kβ photon results when an electron in a target atom jumps from the M -shell to the K shell. The energy of this photon is 25.51 keV − 0.53 keV = 24.98 keV and its wavelength is λKβ = (1240 eV · nm)/(24.98 × 103 eV) = 4.96 × 10−2 nm = 49.6 pm. ...
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This note was uploaded on 11/12/2011 for the course PHYS 2001 taught by Professor Sprunger during the Fall '08 term at LSU.

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