An ion implantation system provides ions to a workpiece positioned in a process environment of a process chamber on a sub-ambient temperature chuck. An intermediate chamber having an intermediate environment is in fluid communication with an external environment and has a cooling station and heating station for cooling and heating the workpiece. A load lock chamber is provided between the process chamber and intermediate chamber to isolate the process environment from the intermediate environment. A positive pressure source provides a dry gas within the intermediate chamber at dew point that is less than a dew point of the external environment to the intermediate chamber. The positive pressure source isolates the intermediate environment from the external environment via a flow of the dry gas from the intermediate chamber to the external environment.