May 2, 2002
Berkeley Lab Research News
FIRST STAGE OF SPALLATION NEUTRON SOURCE COMPLETED
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BERKELEY, CA   Given that all journeys begin with the first step, a big first step has been taken on the road to opening the Spallation Neutron Source (SNS) - what will be the world's premier facility for neutron scattering science. Researchers at the Lawrence Berkeley National Laboratory (Berkeley Lab) have announced the commissioning of the SNS front-end system, the first of that facility's five major components.

(click to view full-size image)
Spallation Neutron Source
Bird's eye view of the front-end system for the Spallation Neutron
Source, the first of that facility's five major components. The system,
designed and built at Berkeley Lab,
will be dismantled after comissioning and shipped to Oak Ridge National
Laboratory which will host the SNS.

The SNS is a $1.4 billion multi-laboratory collaboration sponsored by the U.S. Department of Energy (DOE) to provide the world's most intense pulsed beams of neutrons, the electrically neutral sub-atomic particles that can serve as deep-penetrating, non-destructive probes of solid materials. Located at Oak Ridge National Laboratory (ORNL) in Tennessee and scheduled to begin operations in 2006, the SNS will deliver an average of 1.4 million watts of neutron beam power onto a target -- nearly 10 times the capacity of today's most powerful pulsed neutron sources.

As one of six members of the SNS collaboration, Berkeley Lab has been responsible for the facility's front-end system which generates a beam of negative hydrogen ions and prepares it for delivery into a linear accelerator. From there, these negative ions will be energized to about one billion electron volts in a one-millisecond long pulsed beam and injected into an accumulator ring. Upon entering the ring, the negative ion beam is converted into a proton beam and compressed into one microsecond pulse-lengths. It is then extracted from the ring and smashed into a mercury target to produce neutron beams that can be moderated and guided into designated experimental stations.

"Berkeley Lab is proud to be the first of the SNS partners to deliver our project on time and on budget," said Berkeley Lab Director Charles V. Shank. "This milestone should serve as evidence that a collaboration like this can work, and that DOE laboratories can effectively combine resources to serve our nation's needs."

Said SNS Project Director Thom Mason at ORNL, "As the first SNS partner lab to complete its part of the project, Berkeley Lab is leading the way to successful completion of SNS, on time and on budget. We at Oak Ridge National Lab are grateful for the skill and dedication of the Front End team at Berkeley and the outstanding job it has done."

The SNS front-end system consists of a negative hydrogen ion source, low-energy beam transport (LEBT) system, radio-frequency quadrupole (RFQ) accelerator, and medium-energy beam transport (MEBT) system. A low-energy beam of negative hydrogen ions created in the first two components is passed into the RFQ which groups the beam into discrete pulses and accelerates them to 2.5 million electron volts. The MEBT creates short gaps in the pulsed beam by chopping it into mini-pulses of 645 nanoseconds duration with separations of 300 nanoseconds in order to facilitate the beam's ultimate extraction from the SNS accumulator ring.

"The completion and successful commissioning of the SNS front-end system has been a huge triumph for us and a terrific accomplishment for the Front End team," says Rick Gough, the physicist who heads the Ion Beam Technology (IBT) program for Berkeley Lab's Accelerator and Fusion Research Division (AFRD).

Construction of the SNS front-end system began in October, 1998, and the projected costs for making it were about $20 million. The system was assembled and tested, component-by-component, by a Front-End Group team that included more than 40 scientists, engineers and technicians. Now that the system has been successfully commissioned, its four major components will be separated for shipment to ORNL.

"Shipping to Oak Ridge is scheduled to begin in the first week of June and I am pleased to say that we're on time and within budget," said Gough. "That all of the technical challenges in making this system were so successfully met is a credit to the team effort that has characterized the work of the Front-End Group throughout this project."

In addition to Gough, key members of the Front-End Group included physicist Rod Keller who served as senior team leader with overall responsiility for the SNS Front-End Group, physicist John Staples, who led the design of the RFQ and MEBT, and physicist Rainer Thomae, who led the design of the negative ion source/LEBT, all with AFRD, and project manager Ron Yourd, chief engineer Richard DiGennaro, lead electrical systems engineer Alex Ratti, and lead control systems engineer, Steve Lewis, all with Berkeley Lab's Engineering Division.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California. Visit our Website at www.lbl.gov/. ORNL is a Department of Energy multiprogram research facility managed by UT-Battelle. For additional information about the SNS, visit www.sns.gov