  In high energy astrophysics scenarios such as blazars, GRBs or PWNe, it is
highly probable that ultra-relativistic particles interact with photons in
their environment through scattering. As long as the energy of the particle is
greater than the energy of the interacting photon, the (classical) scattering
is known to be in the Thomson regime. Otherwise, quantum effects will affect
the scattering cross section, and we enter into the so-called Klein-Nishina
regime. It is well known that radiative cooling in the Thomson regime is very
efficient, leading to soft high-energy spectra. However, observations have
shown that, in many cases, the high energy spectrum of some objects is rather
hard. This has led to think that maybe particles are not being cooled down
efficiently. Asymptotic approximations of the Klein-Nishina regime have been
formulated in the last decades in order to account for these corrections in the
distribution of particles responsible for the observed spectrum of high energy
sources. In this work we presenta a numerical approach of the Klein-Nishina
corrections to the radiative cooling. It has been developed to simulate the
evolution of a distribution of particles interacting with photons in their
surroundings via inverse Compton scattering.
