Towards high-precision calculation of electron capture decays.

Based on previous study, the calculation of electron capture decays has been improved by considering a more accurate atomic model with precise atomic energies, and different radiative corrections have been tested. The computer code has been revised in order to greatly speed-up the calculation and has then been coupled with the BetaShape code. The influence of the nuclear component has also been explored using a simple nuclear model. All the calculations are compared with precise measurements available in the literature.