In one embodiment, a pressure control assembly includes a cylindrical hollow body having an opening to receive a ballast gas, a first and second flange, and a first and second cone. The first flange is coupled to a first end of the body, and a second flange is coupled to an opposing end of the body. The first cone is coupled to the first flange, and the second cone is coupled to the second flange. A method for controlling pressure in a chamber includes measuring a pressure of the chamber and a pressure of an exhaust system coupled to the chamber. The method includes dynamically adjusting the pressure in the exhaust system in order to adjust the pressure in the chamber, by creating a first pressure drop that is greater than a second pressure drop in the exhaust system.