he had accelerated sodium and potassium ions to an energy of 50,000 electron volts (50 keV), twice the energy they would have received if accelerated only once by the tube. By successfully accelerating a particle multiple times using the same voltage source, Wideroe demonstrated the utility of radio frequency (RF) acceleration.

This type of linac was limited by the voltage sources that were available at the time, and it was not until after World War II