An Overview of the Spallation Neutron Source Project

The Spallation Neutron Source (SNS) is being designed, constructed, installed, and commissioned by the staff of six national laboratories, Argonne National Laboratory, Brookhaven National Laboratory, Jefferson National Accelerator Laboratory, Lawrence Berkeley National Laboratory, Los Alamos National Laboratory, and Oak Ridge National Laboratory. The accelerator systems are designed to deliver a 695 ns proton-pulse onto a mercury target at a 60-Hz repetition rate and an average power of 2-MW. Neutron moderators that will convert the spallation neutrons into slow neutrons for material science research will surround the target. Eighteen neutron beam lines will be available for users, although initially, only 10 instruments are planned. The FrontEnd Systems are designed to generate a 52 mA, Hbeam of minipulses, 68% beam on, 32% beam off, every 945 ns, at 2.5 MeV for 1 ms, 60 times a second. The Front-End systems include a RF driven, volumeproduction ion source, beam chopping system, RFQ, and beam transport. The linac consists of a drift tube linac up to 86.8 MeV, a coupled-cell linac to 185.7 MeV, and a superconducting RF linac to the nominal energy of 1 GeV. The design of the superconducting section includes 11 cryomodules with three, 0.61-beta cavities per cryomodule and 15 cryomodules with four, 0.81-beta cavities per cryomodule, with space to install six more 0.81-beta cryomodules. The accumulator ring is designed for charge exchange injection at full energy and will reach 2.08x10E+14 protons/pulse at 2-MW operation. The goal is to reduce uncontrolled beam losses to less than 1x10E-4. A detailed overview of the accelerator systems and progress at the various laboratories will be presented.