An apparatus and method is described which may comprise a plasma produced extreme ultraviolet (“EUV”) light source multilayer collector which may comprise a plasma formation chamber; a shell within the plasma formation chamber in the form of a collector shape having a focus; the shell having a sufficient size and thermal mass to carry operating heat away from the multilayer reflector and to radiate the heat from the surface of the shell on a side of the shell opposite from the focus. The material of the shell may comprise a material selected from a group which may comprise silicon carbide, silicon, Zerodur or ULE glass, aluminum, beryllium, molybdenum, copper and nickel. The apparatus and method may comprise at least one radiative heater directed at the shell to maintain the steady state temperature of the shell within a selected range of operating temperatures.