Progress on producing polarized negative hydrogen ions by the ETHZ polarized ion source using the atomic beam method

The progress on the ETHZ polarized negative hydrogen ion source, based on the atomic beam method, is described. Particular improvements have been made in the double charge exchange from positive to negative hydrogen ions. At present the source produces over 100 μA H+ ions, which yields 5−6 μA polarized negative hydrogen ions. These ions have been accelerated, in a EN tandem accelerator. A record current of 2−3 μA of polarized deuterons with 89% polarization could be focused through a 3 mm diameter collimator on a target. Further improvements incorporating presently available techniques are discussed. It is shown that 50‐100 μA of polarized H− and D− ions can be produced with this type of source.