Jefferson Lab in the News
Gearing Up for SNS: Lab Joins Partnership to Build New Federal Laboratory
There's a new kid on the superconducting technologies block, and Jefferson Laboratory is part of the neighborhood welcoming committee.
Jefferson Laboratory has joined national labs Argonne, Brookhaven, Lawrence Berkeley, Los Alamos and Oak Ridge to assist in the design, engineering and construction of the $1.4 billion Spallation Neutron Source (SNS) in Oak Ridge, Tenn. The SNS will provide the most intense pulsed-neutron beams in the world for scientific research and industrial development. Funding is being provided by the U.S. Department of Energy Office of Science, with $8 million in additional monies coming from the state of Tennessee.
Final siting at Oak Ridge was approved almost a year ago, in June 1999, and groundbreaking occurred this past December 15. The SNS is expected to commence operations by mid-2006.
"This is a great opportunity for us to keep our lead in Superconducting Radiofrequency (SRF) technology and help us prepare for future projects such as our 12 GeV upgrade or possibly the Rare Isotope Accelerator," says Christoph Leemann, JLab's deputy director. "Being a part of this effort will help us showcase our technology in support of a science project of national importance. With teamwork and the additional staff we will be hiring, we can manage both Jefferson Lab's mission and our part in building the SNS."
The baseline design calls for an accelerator system consisting of an ion source, a full-energy linear accelerator and an accumulator ring that will combine to produce short, powerful proton pulses. The pulses will strike a liquid mercury target to produce neutrons through a process known as spallation. Neutrons freed by spallation will be slowed down in a device known as a moderator and then guided through beam lines to areas containing specialized neutron detectors and other experimental devices. Once distributed, neutrons of different energies can be used in a wide variety of experiments.
As at JLab, superconducting RF techniques and advanced cryomodules will be incorporated into the SNS design to enable lowcost, high efficiency accelerator operations. "From a JLab standpoint, our core technology is superconducting," says Claus Rode, deputy head of the accelerator division and the Labs senior team leader for the SNS project. "We have an obligation to the taxpayer to transmit our expertise to other government labs. Its an investment thats certainly paid off for us, and we expect similar benefits at the SNS."
A Recent Involvement
Although JLab managers had been involved in SNS discussions early on, it wasnt until this past summer that discussions began to outline the Labs proposed formal participation in the project. By the time groundbreaking occurred in December, JLab was working with the SNS team. Since then, organizers have spent time trying to catch up.
"It's straining a large number of key people because we have to move so fast," Rode explains. "Right now the primary challenge is the schedule. But, we're holding our own.
"The coordination between the labs is a new DOE undertaking. There have been a lot of face-to-face meetings, and a large number of weekly video and audio conferences. It's a very time consuming process. But theres been continual improvement as we learn how to work together."
The Lab will receive approximately $70 million to engineer and assemble most of the SNS cryomodules on site in Newport News and to oversee the installation of refrigeration equipment, cold transfer lines and a superconducting radio-frequency facility at Oak Ridge. Up to a dozen SNS personnel will come to JLab for training and experience in cryomodule assembly. Thus far, JLab-led cavity design is proceeding, with cryomodule layout in progress. The major refrigeration specifications are complete, as are transfer line designs for all standard modules.
A core group of 14 full-time equivalent workers are devoted to the SNS project. Others will be delegated as required. In fiscal years 2002 and 2003 at least 60 Lab staff will be involved. Despite the substantial commitment, Rode believes the Lab will experience few, if any, internal disruptions.
"Our SNS involvement wont affect the efficiency of Lab operations at all," he asserts. "It does have an impact on our 12 GeV upgrade program. In the short term, we'll be rearranging the schedule a bit. In the long run, it will help. We'll have many more people skilled in areas that we'll need in order to accomplish our own upgrade."
Partners Do Their Part
JLab is joining the SNS effort with Lawrence Berkeley National Laboratory, responsible for designing and building the SNS' frontend system, which includes an ion source, beam formation and control hardware, and low-energy beam transport and acceleration systems. Los Alamos has been given responsibility for the SNS linear accelerator, which will speed up a negative hydrogen ion beam from 2.5 million electron volts to 1 billion electron volts. The SNS linac will be a unique concatenation of normal conducting and superconducting radio-frequency cavities and a magnetic lattice that provides focusing and steering.
Brookhaven has been charged with the accumulator ring structure, which bunches and intensifies the ion beam for delivery onto the mercury target to produce the pulsed neutron beams. Because of the enormous amount of energy that the short but powerful pulses of the incoming 1GeV proton beam will deposit in the spallation target, designers have opted to use liquid mercury as a target, rather than a solid such as tantalum or tungsten. The SNS will be the first scientific facility to use pure mercury as a target for a proton beam. Oak Ridge will be responsible for target design and construction.
Argonne is primarily responsible for developing the neutron-scattering instrumentation for the SNS and for working closely with Oak Ridge to develop the experiment facilities.
"We are quite pleased to have JLab join the SNS partnership, as they bring a very high level of technical talent and superconducting accelerator experience with them," says David Moncton, executive director for the SNS at Oak Ridge National Laboratory. "Their proven record of success constructing and bringing the Continuous Electron Beam Accelerator Facility on line is a real plus for this project, and the demonstrated commitment of all the partner lab directors is proving very effective in completing the SNS design and starting construction of the worldclass neutron scattering research facility expected by the user community."