The Fokker-Planck equation is solved for alpha particles in a tokamak, including both pitch angle scattering and slowing down. Losses of the toroidally trapped particles due to stochastic diffusion related to magnetic ripple are accounted for by assuming that all the stochastic orbits leave the device immediately. This assumption permits the problem to be solved by the introduction of a loss cone corresponding to the stochastic region of the velocity space. The eigenvalue problem is solved numerically, to show that the additional stochastic loss of energy due to scattering into the loss cone substitutes about 30% of the birth energy for typical fusion parameters