A stationary CT system comprising at least one annular x ray source assembly comprising a plurality of respective x ray sources spaced along the annular x ray source assembly. Each of the x ray sources comprises a respective stationary x ray target, an electron beam focusing chamber; an x ray channel; an electron beam source disposed in a spaced apart relationship with respect to the respective stationary x ray target; a vacuum chamber disposed in between the electron beam focusing chamber and an insulating chamber where the insulating chamber houses the electron beam source; a radiation window at a pre-defined angular displacement from the respective stationary x ray target and the x ray channel; and a target substrate attached to the respective stationary x ray target.