Innovative device producing double-layer cryogenic pellet

An innovative device for producing a double-layer pellet is designed, constructed and operated for the purposes: (1) efficient fueling of a specific species such as tritium in the plasma core region, (2) controlled deposition of specific minority ions in the plasma core region for efficient ICRF heating, (3) establishment of an accurate transport diagnostic system to measure particle transport both parallel and perpendicular to the magnetic field lines of magnetic confinement devices. For the precise set-up of the cryohead, special techniques have been used, and the whole device has been successfully constructed. It has been shown that the positioning accuracy under cooling with liquid helium is about 10 μm. The production of a pellet having a void has been proved with a photograph of the ejected pellet taken by a fast flash lamp during flight