High vacuum plasma pumping offers an important, attractive, and viable method of producing vacua. Since no mechanical moving parts are employed, it is inherently rugged. Moreover, it can achieve high values of hydrogen and helium throughput with excellent flexibility and speed. A high vacuum plasma pumping method, the plasma vacuum pump (PVP), that uses electron cyclotron heating (ECH) to achieve t se in advantages in practice has been developed. A complementary, non-mechanical plasma booster pump stage can greatly extend the application range of plasma pumping methods by matching the PVP pumping speed at higher working pressures than are feasible for the PVP. The resulting pumping system could be completely free of sources of oil streaming and thus provide a "dry" system. Additionally, the augmented PVP would retain the inherent ruggedness and capability for rapid up-down cycling of the low pressure PVP. The booster stage is designed to compress the axial plasma flow from the PVP by a factor of 500 to 1,000. This permits high gas throughput at working pressures up to 10 mtorr to be exhausted into a dry mechanical pump (e. g., a diaphragm pump), at approximately 1 torr. To achieve this performance, Phase I will develop a novel concept called the Rotating Plasma Compressor (RPC). This employs the basic phenomenology of rotating plasmas, established several decades ago, that can be readily adapted to the present application.Anticipated Results/Potential Commercial Applications as described by the awardee:A plasma vacuum pump system composed of a PVP matched to an RPC would provide a rugged, dry (oil-free), high speed method of pumping ideally suited to meet the needs of the semiconductor processing industry, scientific laboratory applications, and large fusion power devices. The pairing of a plasma booster vacuum pump with the ECH-driven plasma finishing pump would greatly enhance the commercial and scientific desirability of both plasma vacuum pump elements. Phase II development should provide a clear demonstration of the technical viability of the RPC concept.
