The dream beam at the Los Alamos Neutron Science Center still delivers.
September 1, 2022
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.
1972 Linac
LAMPF first achieved 800 MeV on Louis Rosen’s 54th birthday, June 9, 1972. Scientists used the intense linear accelerator (LINAC) beam to produce pi-mesons, or pions, and their decay products (muons, electrons, and muon neutrinos). Studying these subatomic particles enabled scientists to probe the fundamentals of the spin-orbit force and the symmetries and dynamics of the Standard Model of Particle Physics. In addition, taking advantage of the fact that protons can be used to create new isotopes, the Lab began producing difficult-to-obtain radioisotopes for use in medical diagnostics and treatments.
1977 WNR
The Weapons Neutron Research (WNR) Center opened in 1977 with a heavy-element target that produces neutrons when hit with the proton beam, a process called spallation. Spalled off neutrons are directed to tunnels called “flight paths” for use in various experiments, including: studying radiation effects, obtaining nuclear data for weapons design, or mimicking the neutron spectra in the atmosphere from cosmic rays. This latter capability supports industry partners in analyzing the impact of cosmic radiation on electronics such as airplane components, high-performance computers, and medical devices. opened in 1977 with a heavy-element target that produces neutrons when hit with the proton beam, a process called spallation. Spalled off neutrons are directed to tunnels called “flight paths” for use in various experiments, including: studying radiation effects, obtaining nuclear data for weapons design, or mimicking the neutron spectra in the atmosphere from cosmic rays. This latter capability supports industry partners in analyzing the impact of cosmic radiation on electronics such as airplane components, high-performance computers, and medical devices.
1985 Lujan
In 1985 LAMPF opened the Los Alamos Neutron Scattering Center, now known as the Lujan Center (in honor of New Mexico politician Manuel Lujan Jr.), which includes a proton storage ring (PSR) to compress proton pulses from 750 microseconds to a quarter of one microsecond. The Lujan Center houses a tungsten spallation target and uses liquids to moderate, or slow, the neutrons for seven different flight paths. Experiments include basic science questions about the origins of the universe, characterizing unstable nuclei in materials for clean energy, or elucidating the crystalline structure of transition metals for use in computers.
1997 pRad
Proton radiography (pRad) was developed at LANSCE in the late 1990s as a new way to image explosions. Using magnets as lenses to focus the protons, and with the full strength of the proton beam, an image can be produced every 100-200 nanoseconds. These images can be stitched together into extraordinary “motion pictures.” In the absence of nuclear testing, these images are critical to the Laboratory’s mission of maintaining the nation’s stockpile by giving scientists valuable data on detonation and how materials perform at various ages and stages. was developed at LANSCE in the late 1990’s as a new way to image explosions. Using magnets as lenses to focus the protons, and with the full strength of the proton beam, an image can be produced every 100-200 nanoseconds. These images can be stitched together into extraordinary “motion pictures.” In the absence of nuclear testing, these images are critical to the Laboratory’s mission of maintaining the nation’s stockpile by giving scientists valuable data on detonation and how materials perform at various ages and stages.
2004 IPF
In 2004, LANSCE opened the Isotope Production Facility (IPF) to make isotopes for application in the fields of medicine, fundamental nuclear physics, national security, environmental science, and more. Normally, once a method to produce a sought-after isotope has been refined by the Lab, the method transitions to industry for mass production. However, in 2020 when many industries were offline due to the COVID-19 pandemic, the IPF stepped up production to keep critical medical isotopes in ample supply. LANSCE opened the Isotope Production Facility (IPF) to make isotopes for application in the fields of medicine, fundamental nuclear physics, national security, environmental science, and more. Normally, once a method to produce a sought-after isotope has been refined by the Lab, the method transitions to industry for mass production. However, in 2020 when many industries were offline due to the COVID-19 pandemic, the IPF stepped up production to keep critical medical isotopes in ample supply. LANSCE opened the Isotope Production Facility (IPF) to make isotopes for application in the fields of medicine, fundamental nuclear physics, national security, environmental science, and more. Normally, once a method to produce a sought-after isotope has been refined by the Lab, the method transitions to industry for mass production. However, in 2020 when many industries were offline due to the COVID-19 pandemic, the IPF stepped up production to keep critical medical isotopes in ample supply. supply.
2005 UCN
The Ultracold Neutron Facility (UCN) employs a solid deuterium crystal to cool neutrons by one million billion-fold, so that they move at speeds of only a few meters per second. Ultracold neutrons can be completely confined by magnetic fields and gravity for minutes at a time. With this capability, in 2021 Lab scientists measured the neutron lifetime, cutting the uncertainty of the previous best measurements in half.
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.