I attach the paper.
non_collinearity.pdf (387.0 KB)
Fig. 3 shows the energy distribution, centred in 511 keV, with a spread of 2.68 keV FWHM. They claim that the distribution of the deviation from 180 deg of the angle between the two gammas comes from Eq. 6, and should be a gaussian centred in 0 with a sigma of 0.54 degrees.
I attach the plot of the energy of my gammas, which appear to be exactly 511 keV, with no spread (so, different from Fig. 3) and also the plot of the angle between the gammas (different from a gaussian with 0.54 degrees FWHM, too).
