PPA beam extracted

After a year of effort physicists at the Princeton‐Pennsylvania accelerator have succeeded in extracting the synchrotron's beam. The method of extraction, which is the same as the one used on the electron accelerator at Frascati, employs betatron oscillation to blow up and spill the beam. Specifically the radial betatron resonance, $vr = 2/3,$ is excited so that the radial oscillations of the beam build up and move the protons so far from the equilibrium orbit that they find their way into the field of an extraction magnet that bends them out of the accelerator.