Rolf Wideröe

…years later, the Norwegian engineer Rolf Wideröe built the first machine of this kind, successfully accelerating potassium ions to an energy of 50,000 electron volts (50 kiloelectron volts).

…resonance accelerator was demonstrated by Rolf Wideröe in 1928. At the Rhenish-Westphalian Technical University in Aachen, Ger., Wideröe used alternating high voltage to accelerate ions of sodium and potassium to energies twice as high as those imparted by one application of the peak voltage. In 1931 in the United States,…