A continuous lithium atomic beam source for cryogenic apparatus

We have created an atomic beam source of lithium atoms for use in a cryogenic environment. This beam source is expected to provide a flux of 10 to the 18 atoms/s. The main features of this source are a reservoir chamber of solid lithium heated with heater wire, creating a lithium gas that travels down an ohmically heated tube and exits as an effusive beam. That beam is directed at a cold supersonic jet of helium. As lithium atoms enter the helium gas they rapidly thermalize and become entrained. The design challenges faced included directing the heat load away from the cold elements of the cryogenic chamber, obtaining the correct temperatures to provide the desired flux, and measuring the beam as it exited the reservoir. Through the use of laser induced fluorescence, we believe we have observed capture of lithium by the helium jet. Such a beam source can be used to form an intense cold atom source with the potential future application of serving as a pump source for an atom laser.