Beam Emission Spectroscopy (BES) is an important method of fusion diagnostic technology. One version of it is the Lithium BES which is widely used for edge plasma density profile and turbulence measurements. Time resolution of the diagnostic is limited by the lithium beam emission and thus the beam current, therefore developments are necessary to improve the beam current. In 2013, an upgrade of the JET Lithium-Beam injector has taken place. On step of the upgrade was to replace the ion source with a new carbon disk heating type in order to provide longer lifecycle and more extracted ion current with appropriate focusing. The new source needs higher heating power which causes high temperatures in the high voltage, vacuum system environment, and affects stability. The main aim of this paper is to show a mechanical engineering solution for the increased heating power dissipation in such environment by active cooling elements.