According to a joint announcement by Princeton University, the University of Pennsylvania, and the Atomic Energy Commission, the recently completed Princeton‐Pennsylvania Proton Accelerator has successfully produced a beam of protons at its design energy of 3 BeV. The machine, a uniform‐gradient synchrotron, is located at the Forrestal Research Center in Princeton and was built at a cost of $12 million, most of which was supplied by the Atomic Energy Commission.