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Bethe Stopping Power

  1. Nov 27, 2009 #1
    The nonrelativistic Bethe stopping power function contains the constant 2*pi*N*e^4 where N is Avogadro's number and e is the electron charge. In the literature, this constant is often calculated to be 78,500. If calculate the constant, I get 606,235 (=2 * pi * 6.02214179E+23 mol^-1 *(1.602176487E-19 C)^4). Does anybody know what my mistake is?

    Thank you.
  2. jcsd
  3. Nov 27, 2009 #2
    I usually use the Bethe Bloch equation in the form
    and substitute

    e2/(4 pi ε0) = re mec2
    where re is the classical electron radius (2.818 x 10-13 cm) and
    mec2 is the electron rest mass
    which is 511,000 eV (one of which cancels in the denominator)

    See my posts #8 and #9 in thread

    Bob S
    Last edited: Nov 27, 2009
  4. Nov 27, 2009 #3
    Thank you. That helped.
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