Conduit 303 is fluidly separated from the vacuum-containing portion of PVD chamber 100, for example by a cover plate (not shown) or by a portion 308 of annular structure 300. In the embodiment illustrated in FIG. 3, portion 308 of annular structure 300 fluidly separates conduit 303 from the vacuum-containing portion of PVD chamber 100. As a result, there are two welds separating cooling liquid in conduit 303 from the vacuum-containing portion of PVD chamber 100: the weld sealing conduit 303 from cavity 310 and the weld sealing cavity 310 from the vacuum-containing portion of PVD chamber 100. Therefore, the failure of two welds must occur before cooling liquid in conduit 303 can leak into the vacuum-containing portion of PVD chamber 100. Alternatively, in some embodiments, some or all of annular structure 300 is formed via a 3D printing process. In such embodiments, conduit 303 can be formed without a separately welded cover 311, which further reduces the potential for leakage of the cooling liquid from conduit 303.

In the embodiment illustrated in FIG. 3, coil portion 130 includes wire or other conductors that are substantially square in cross-section. Alternatively, in other embodiments, coil portion 130 can include conductors that are circular or rectangular in cross-section.