THE FILTEX HERMES POLARIZED HYDROGEN ATOMIC-BEAM SOURCE

The FILTEX/HERMES atomic beam source (ABS) for polarized hydrogen is described. Recent improvements concern mainly the optimization of the beam forming system and a new design of the sextupole magnet system. For a precise measurement (error 5%) of the output flow a calibrated compression tube was installed. The output flow of 0.81 x 10(17) H atoms per second in two hyperfine substates was constant within 2% in a long-term measurement lover 16 h. At the FILTEX test experiment, the target density in the storage cell fed by the ABS was constant within the experimental error of 4% over a period of four months.