The Spallation Neutron Source – A New World-Class Scientific Facility

The Spallation Neutron Source located at Oak Ridge, TN, is a next-generation neutron-scattering facility presently under construction as a collaborative effort of six national laboratories. The facility is comprised of a high-power particle-accelerator system, a liquid-mercury target-moderator system, and a suite of world-class scientific instruments. One-ms-long negative-hydrogen-ion (H-) pulses are produced by an ion source. The ion beam is accelerated to 185 MeV by three types of normal conducting (NC) linear accelerator (linac) structures. Beam is further accelerated to 1 GeV by a superconducting linac, with 81 niobium superconducting radiofrequency (SRF) cavities that operate at 2.1K. The 1-ms-long linac beam is stacked in a compressor ring and 695-ns-long pulses are extracted onto the target. Neutrons are produced by spallation in the mercury, and their energy is moderated to useable levels by supercritical hydrogen and water moderators.

Marion M. White received her Ph.D. in experimental particle physics from MIT, searching for new particles at the PETRA collider at DESY. As a detector specialist, she led a multinational group responsible for producing the large precision muon chambers for the L3 detector at CERN. She remained with the MIT group at CERN until 1991, when she moved back to the USA and joined the Advanced Photon Source (APS) at Argonne National Lab. Marion served as linac group leader, responsible for the successful construction and commissioning of the APS’s electron-positron injector linear accelerator, after which she served as linac manager for five years.

In 1999, she began working full-time on the Spallation Neutron Source (SNS) linear accelerator, helping to finalize the accelerator design, build up the accelerator division at Oak Ridge, and change most of the SNS linac to superconducting technology. Dr. White presently serves as senior scientific advisor to the accelerator systems division director at the SNS project in Oak Ridge, TN, and has oversight responsibility within the division for front end and linac construction.

She has served on program and organizing committees for PAC and LINAC conferences, is a frequent participant in outreach programs to students and women, and is a member of the APS, AAUW, and AAAS.