link to lecture transcript - UT-H GSBS Medical Physics Class Site

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Next we want to calculate the energy transfer coefficient. We have calculated the total attenuation coefficient, which tells us the fraction of photons attenuated per unit path length. We want to calculate the energy transfer coefficient to determine how much energy is transferred to the electrons as a result of the interactions. In order to do so, we take the linear attenuation coefficient and weight it by the fraction of the incident photon energy that is transferred to the electrons. This fraction is equation to the amount of energy transferred to the electrons divided by the incident photon energy. energy 10
The energy transferred to the electron is given by this equation; we derived that in the previous lecture. The fraction of energy transferred to the electrons is this quantity divided by hν. So dσ tr/dΩ is ½ r 0 2 times 1+ cos 2 θ , that is, the classical quantity, times the Klein-Nishina coefficient times the ratio α(1 – cos θ) divided by 1 + α(1 – cos θ). 11
Page 1 and 2: Today, we continue our talk about C
Page 3 and 4: We previously derived an equation f
Page 5 and 6: So σ 0 is the classical cross sect
Page 7 and 8: Let’s look at this graph. Notice
Page 9: What about the dependence of the Co
Page 13 and 14: If we plot the energy transfer coef
Page 15 and 16: The energy transfer coefficient has
Page 17 and 18: What about the scatter coefficient?
Page 19 and 20: Using this equation we can now plot
Page 21 and 22: This probability is represented by
Page 23 and 24: This figure is a plot taken from Jo
Page 25 and 26: We can always calculate what the ma
Page 27 and 28: Remember dσ/dE is relatively const
Page 29 and 30: Now we also look at the graph and s
Page 31 and 32: First, let’s recall that the atte
Page 33 and 34: What we now want to find out is how
Page 35 and 36: So far, our approximations have bee
Page 37 and 38: These values were tabulated by Hubb
Page 39 and 40: So what is the effect of binding en
Page 41 and 42: At higher energies there is no diff
Page 43 and 44: Note that this graph is for very lo
Page 45: The fraction of energy transferred

link to lecture transcript - UT-H GSBS Medical Physics Class Site

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