Low capacitance electrical feedthrough and simple, reuseable closure seal for hydrostatic pressures to 7 kilobar and temperatures to 200 °C: application to NMR

An electrical feedthrough having a capacitance of 7 pF is described. It consists of a stack of two right circular cylinders, one an insulator, and one a metal with polyimide gaskets appropriately placed. A very simple, reuseable, polymeric closure seal is also described. The seal is patterned after the ``C'' seal and features easy extraction and sealing on the small bore of the pressure vessel. The closure seal and feedthrough have been tested to 7 kilobar at room temperature and 5 kilobar at 200 °C without failure.