Production of intense beams of polarized negative hydrogen ions by double charge exchange in alkali vapours

In the last few years substantial progress on the performance of the electron impact ionizer and the double charge exchanger has been made in our laboratory. A proton or deuteron beam intensity of over 100 μA has been observed in the positive stage of the source. A polarized negative ion intensity of 6 μA was obtained after the charge exchange. After acceleration in the ETH EN‐tandem accelerator 2 to 3 μA of polarized deuterons with 90% polarization could be focussed through a 3 mm diameter collimator on a target. This is the highest value ever reported for an accelerated beam.At present we investigate improvements of the atomic beam stage. With presently available techniques some 100 μA of polarized H− and D− ions can be obtained with this type of source. New developments suggest that it is possible to reach in the future a beam intensity in the mA range.