Muonic atom generation

The simulation was started by creation of a muonic atom in the emission layer. The spatial distributions, both in the beam direction z and in the radial direction r, of the muonic atom generation could be controlled by the input file. A uniform distribution in z and a Gaussian distribution with a flat top in r were used as nominal input. For determination of the radial beam distribution, see Section 6.1. The fraction of muonic protium to muonic tritium $\mu t$ was proportional to that of protium to tritium in the target. The initial energy of the muonic atom was taken to be a Gaussian distribution with mean 1 eV and standard deviation 1 eV. Hyperfine states of muonic atoms were populated with the statistical weights, i.e., 25% F=0 and 75% F=1 for both and $\mu t$, which are composites of two spin one half particles.