Virtual Tour

An ion's trip through the beamline is nearly three miles long. The illustration shows a few stops along the beamline. Each stop is highlighted below.

Illustration of the beamline, which highlights 14 detectors and stops along the beamline.

  1. In the ion sources, vapor of a particular atomic species is “held” in a magnetic field and ionized by removing electrons. The ions are then extracted and injected into the first cyclotron, the K500. YouTube video of ion sources.

  2. Ions of a stable isotope are first accelerated by the K500 cyclotron, and subsequently by the K1200 cyclotron. The cyclotrons use strong electric fields to accelerate the ions, while a strong magnetic field  contains their outward spiraling orbits. The final ion velocity is about 93,000 miles per second or close to half the speed of light. YouTube video of cyclotrons.

  3. The intense fast beams of stable isotopes hits a production target. Many different isotopes are produced through nuclear reactions, including the ones of interest for a particular experiment.

  4. By carefully tuning the magnetic fields in the A1900 fragment separator, the desired isotopes are filtered out from the others. The A1900 can separate one isotope from a million times a billion others! YouTube video of A1900

  5. The Modular Neutron Array (MoNA-LISA) detects fast neutrons produced in nuclear reactions, providing both the velocity and direction of the neutrons. Meanwhile, the charged particles are swept into a dedicated detector system by a “Sweeper” magnet. By combining location and velocity information for both sets of particles, the reaction can be reconstructed and detailed info on very neutron-rich isotopes measured. YouTube video of MoNA-LISA and the Sweeper Magnet 

  6. The Radiofrequency fragment separator provides a second stage of isotope separation (after the A1900 separator) and is particularly useful for filtering out proton-rich rare isotopes. YouTube video of the Radiofrequency fragment separator

  7. At the Decay Station, unstable isotopes are stopped inside a detector.  This provides signals to determine the isotope species and also detects charged particles emitted when the unstable isotope decays. Other systems surrounding it can detect other decay products, such as gamma rays and neutrons.

  8. The S800 spectrometer can precisely measure the velocity of isotopes generated when the beam hits a target. A suite of detectors (like LENDA and GRETINA) also enables the identification of the isotope species. By combining that data with data obtained from detectors for charged particles, very detailed information about the structure of the unstable isotopes and the reactions they make can be extracted. YouTube video of the S800 and LENDA and GRETINA

  9. At the gas stopping stations, the beam of fast unstable isotopes is slowed down from about 90,000 miles per second to a “mere” 1500 ft per second. These slowed isotopes are then fed into different experimental areas for high-precision measurements with low-energy particles.

  10. In the Laser Spectroscopy area, researchers inject different colors of laser light into the slowed  isotopes coming from the gas stopping stations. The isotopes in the beam will fluoresce as a response, and the emitted light is detected, providing detailed information about the shape, size, and spin of the rare isotopes.

  11. At the Low Energy Beam and Ion Trap (LEBIT) unstable isotopes are trapped by using a combination of magnetic and electric fields, allowing for a detailed study of their properties. For example, the mass of unstable nuclei can be measured with a precision of better than 100 parts per billion! YouTube video of LEBIT

  12. The reaccelerator provides high-quality low energy unstable isotope beams by reaccelerating the unstable isotopes to a velocity of about 15,000 miles per second (10% of the speed of light). This is a typical velocity of nuclei in stars, allowing for the study of nuclear reactions that unstable nuclei undergo in a star. YouTube video of reaccelerator

  13. This provides the world’s highest-density helium jet so rare isotope beams can interact with the gas and produce low-energy reactions that would occur in novae, X-ray bursts, and supernovae!

  14. The Active Target Time Projection Chamber (AT-TPC) enables tracking of charged particles that are generated when a rare isotope from the reaccelerator reacts with an atom in the gas inside the Chamber. It is like taking a snapshot of the nuclear reaction!