VENUS neutron imaging beamline

The VENUS instrument is currently under construction at the Spallation Neutron Source (SNS). Planned for completion in 2024, VENUS will be one of the most state-of-the-art beamlines for neutron imaging that will enable exciting new ways of studying a wide range of diverse materials currently not possible for open research programs in the U.S.

Neutron imaging is a powerful technique used to generate pictures of the internal structure of materials. The images, called radiographs, are similar to clinical x-rays that use contrast variations to reveal the internal structure of objects as neutrons are absorbed or deflected by different atoms inside a material.

Whereas the IMAGING beamline at the High Flux Isotope Reactor (HFIR) utilizes a steady-state or constant beam of neutrons, VENUS will feature time-of-flight capabilities enabled by the SNS pulsed-source accelerator. Leveraging the time-of-flight capability, VENUS combines the properties of diffraction and spectroscopy that will allow users to simultaneously collect data on both the structure and behavioral dynamics of materials at the atomic scale.

Construction milestones to date

Physical construction of the beamline began in 2019. With the majority of foundational work coming to a close, such as pouring concrete and installing heavy steel components, construction is shifting to focus on shielding and support structures for shutter inserts and optical components. To date, major construction milestones include:

  • Chopper shelves: Two layers of concrete were poured, raising the floor to provide a shelf for the choppers—the large metal disks that rotate 3,600 times a minute with defined openings to select neutrons of specific velocities and, thus, to create the pulses of neutrons with the desired range of energies.
  • Bulk shield insert: The bulk shield insert is a stainless steel box—bolted to the thick concrete wall separating the instrument hall from the liquid mercury target—that provides a mounting bracket for the installation of other equipment such as the chopper, the beam shutter, and the neutron flight tube, the line neutrons travel from the source to the instrument.
  • Chopper cavity shielding: An 8,000-pound steel frame installed around the bulk shield insert provides support to the chopper and other equipment, as well as support for “roll-in shielding blocks.”
  • POWGEN shielding: A series of complex shielding modifications were made to the neighboring POWGEN instrument, BL-11, to accommodate the poured-in-place concrete shielding for VENUS.
  • Core-vessel insert and shutter: Both the core-vessel insert and the shutter have been installed into the monolith, as well as upgraded shutter drive rods on several operational shutters.