We propose to measure the collective spin excitations over a wide energy range in BaFe2-xCoxAs2 (x=0.22). This compound is one of the FeAs based superconductors which have recently been discovered. These materials can have transition temperatures up to 55 K and are believed to be magnetically mediated. BaFe2-xCoxAs2 is an electron doped system in contrast to the widely studied hole doped material Ba1-xKxFeAs2. We would measure the magnetic excitations up to high energy and look for a special "magnetic resonance mode" which occurs only in the superconducting state.