Lithographic apparatus and a vacuum chamber

A lithographic apparatus includes an illumination system configured to condition a radiation beam and a support constructed to support a patterning device. The patterning device is configured to impart the radiation beam with a pattern in its cross-section to form a patterned radiation beam. A substrate table is constructed to hold a substrate, and a projection system is configured to project the patterned radiation beam onto a target portion of the substrate. The projection system includes a vacuum chamber and a controller configured to control an actuator of an optical device arranged in the vacuum chamber. The vacuum chamber includes a hermetically sealed housing in which the controller is accommodated. The housing is provided with an electrical connection configured to electrically connect the controller to the optical device, and is connected to an exterior wall of the vacuum chamber via a fluid cooling channel configured to cool the controller.