Manhattan project veteran Louis Rosen spent decades after the war pioneering techniques to measure the neutron spectra of weapons materials. While on sabbatical in Paris, in 1959, Rosen envisioned a nuclear science facility at Los Alamos with the world’s most powerful, high-intensity-proton linear accelerator. This dream—the Los Alamos Meson Physics Facility (LAMPF)—opened in 1972 with an 800-million-electron-volt (MeV) accelerator, which was four times more intense than the 200 MeV achieved by other accelerators at the time. The LAMPF accelerator, uniquely, could accelerate both H+ and H− particles and was the first to be remotely operated by computers. This versatile proton beam is still used directly for some experiments and indirectly to produce neutrons for others. For 50 years, LAMPF—now LANSCE (Los Alamos Neutron Science Center)—has facilitated the advancement of fundamental nuclear physics while solidly supporting the Laboratory's national security mission.
At 50 years old, the dream beam still delivers and will continue to drive future science and innovation. The front end of the accelerator is being updated and the Lujan Center got a new spallation target this year. The new target will increase, by a factor of 50–100, the number of neutrons with kiloelectron-volt energies, which will enable nuclear physics experiments that were previously not possible. Visions of new experimental capabilities—even a possible x-ray-free electron laser facility—populate the roadmap for LANSCE to the year 2050 and beyond.