July 9 talk planned on proton power upgrade as the SNS at ORNL returns to operation

Neutron production for scientific users of the Spallation Neutron Source at Oak Ridge National Laboratory is expected to resume Thursday, July 11. Two days before on Tuesday, July 9, Mark Champion will explain to Friends of ORNL what progress has been made since the SNS was shut down last August to make the accelerator-based facility an even more powerful, world-leading spallation source.

The SNS provides intense neutron beams to scientific instruments for understanding how atoms arrange themselves and move in physical and biological materials, and for designing materials with improved properties for industry.

After accelerating negative hydrogen ions and then stripping them of all electrons to produce bunches of high-energy protons in an accumulator, the SNS delivers short pulses of protons - 60 times a second - to a mercury target system, called the first target station (FTS). There neutrons are knocked out of mercury nuclei (spallation) and sent through neutron beam lines to instruments for experiments and data collection.

Champion, project director of the Proton Power Upgrade (PPU) at the SNS in the Neutron Sciences Directorate, will speak on the PPU at noon July 9 at the UT Resource Center, 1201 Oak Ridge Turnpike. He will detail the progress made by the project over the past 10 months.

He will also talk about future work to create a third neutron source for scientists at ORNL through construction of the second target station (STS, which will have a tungsten target), to be completed by 2032. Currently, ORNL’s two neutron sources are the SNS and the High Flux Isotope Reactor. A third source would likely preserve ORNL’s world leadership in neutron science in the next decade.

Sandwiches, chips, cookies and drinks will be available at 11:15 a.m. at the UT Resource Center for a donation of $10 on a first-come, first-served basis. To view the virtual presentation, click on the talk title on the www.fornl.org website homepage and then click on the Zoom link near the bottom of the page describing the lecture. You can view it the next day by clicking on “Past Talks” on the left side of the website’s navigation bar.

Champion said in his submitted summary of his July 9 talk that the PPU “will increase the proton beam power capability from 1.4 to 2.8 megawatts (MW). Upon completion in early 2025, 2 MW of beam power will be available for neutron production at the existing FTS with the remaining beam power available for the future STS.

“The project has installed seven superconducting radiofrequency (RF) cryomodules and supporting RF power systems to increase the beam energy by 30% to 1.3 giga electron volts (GeV), and the beam current will be increased by 50%. The injection and extraction region of the accumulator ring have been upgraded, and a new 2-MW mercury target was developed along with supporting equipment for high-flow gas injection to mitigate cavitation and fatigue stress.

“The first four cryomodules and supporting systems were commissioned in 2022-2023 and supported neutron production at 1.05 GeV, 1.7 MW with high reliability. The first-article 2 MW target was operated successfully for approximately 4400 MV-hours over two run periods.

“During the long outage the remaining technical equipment was installed. The Ring-to-Target Beam Transport tunnel stub was constructed, enabling a connection to the STS without interrupting operation of the FTS.”

Champion began his career at the U.S. Department of Energy’s Fermilab upon completion of his university studies. At Fermilab he learned about accelerator technology, contributed to superconducting radiofrequency (SRF) technology research and supported accelerator operations and upgrades.

He joined the SNS construction project in 2001 and worked on the design, construction and commissioning of the accelerator complex. In 2007, he returned to Fermilab to lead the SRF Department in the execution of International Linear Collider research and the establishment of a world-class SRF program.

In 2012, he returned to SNS as the group leader for Electrical and RF Systems. He began supporting the PPU project in late 2016, initially as the Level 2 manager for RF Systems. He transitioned to the PPU project manager role in 2017 and became its project director in 2024.