Certain embodiments described herein are directed to couplers that can be used to provide a seal between a source assembly and a vacuum chamber. In certain examples, the seal can be provided upon movement of a moveable component of the coupler. In some examples, rotation of the moveable component is operative to provide an axial force to a stationary component coupled to the moveable component such that the stationary component is biased to provide a suitable seal to the vacuum chamber.