Neutron Sciences Directorate

The original SNS plans included provisions for a second target station. Working closely with the scientific community, ORNL will continue to refine the conceptual design including the accelerator, target system, and instruments.

• Accelerator: The existing SNS accelerator was designed to allow upgrades needed to support a second target station. Accelerator modifications will increase the power of SNS; the existing target station will receive 45 proton pulses per second while 15 pulses per second will be redirected down a new transport line to the second target station.

• Target System: The second target station will be 25x brighter neutron source than the first target station. The proton pulse reaching the target will have one-half the footprint of and produce neutrons in a much smaller volume than those reaching the first SNS target. Advanced moderators located adjacent to the active target region will lower the neutron energies to those required by the instruments. To manage volumetric heating, the tungsten target will rotate during use so that only 5 percent is active at any one time. Together, the compact proton beam footprint on the target and advanced moderator designs will significantly enhance neutron brightness compared to the first target station.

• Instruments: A repetition rate of 15 pulses per second will enable operation of large bandwidth instruments. The range of wavelengths accessed in a single pulse will be 4x greater at the second target station than the first target station for a given instrument length. STS will support a complement of 22 total instruments which will be selected with input from the science community. With a new suite of world-leading instruments boasting the latest advances in high-resolution optics, instrument design, and neutron spin manipulation, the STS will deliver instrument-specific performance gains 100x to 1,000x better than existing instruments.