Drawing a parallel to \(y = mx + b\), the slope of the graph is \((m_ec^{2})^{-1}\) which is a constant. Therefore, the plot of \(E^{'-1}\) vs.  \((1-cos(\theta))\) can be drawn by obtaining the photopeaks at each angle and the slope should be equivalent to the inverse of the electron mass energy, 0.511 MeV.  
    For differential cross section, the theoretical model predicts the value for the differential cross section using K-N equation and Thompson formula. However, the two results are incomparable at a high energy such as 0.662 MeV or an angular variance of 110 degrees. The figure 5 shows the theoretical plot for the both equation at \(\gamma\) = 1.29.