Source for atomic beams of metastable gases: Design and performance

There is an increasing interest in high flux sources of metastable species in many scientific communities, for example for lithography and quantum optics experiments. We present a simple dc discharge design, based on microstructured electrodes (MSE), for the production of truly thermal beams of metastable atoms. Even for inlet pressures above 1 atm the discharge runs stably, at relatively modest voltages. Time-of-flight data prove that the expansion is supersonic with speed ratios up to 8.5 and internal temperatures of less than 10 K. The MSE source works equally well for many different gases like He, Ne, Kr, Ar, H2, and N2. Its measured yield of ∼1014 metastable atoms s−1 sr−1 compares favorably with conventional discharge sources. In addition, its simple design holds good promise for cooling the source down to cryogenic temperatures.