Tandem Accelerator Bay

The main accelerator is a FN tandem Van de Graaff accelerator that has a maximum terminal voltage of 10 MV. Negative ions can be injected into the tandem from three sources: (1) a direct extraction negative ion source provides pulsed or dc beams of unpolarized H- and D- ions, (2) an atomic beam polarized ion source provides dc beams of polarized H- and D- ions, and (3) a heavy-ion source provides dc beams of helium ions. After acceleration, momentum analyzed beam can be delivered to any one of six beam lines. The main target-room equipment includes two general-purpose charged-particle scattering chambers, a gas-jet target and associated charged-particle scattering chamber, a neutron time-of-flight spectrometer system, and an Enge split-pole magnetic spectrometer. The tandem laboratory also houses the Low-Energy Beam Accelerator Facility (LEBAF) which provides users with polarized and unpolarized beams of protons, deuterons and helium ions from 20 to 680~keV. The LEBAF is located in the low-energy bay of the tandem laboratory with beam lines connected to the analyzing magnet at the output of the polarized ion source. The LEBAF is equipped with a 200-kV mini-tandem accelerator and two scattering chambers, one that can be biased to 200 kV. Beam for LEBAF comes from the atomic beam polarized ion source which outputs polarized and unpolarized beams of H+/- or D+/- ions and beams of helium ions at energies from 20 to 80 keV. The combined use of the mini-tandem and the 200-kV high-voltage scattering chamber extends the upper energy reach of LEBAF to 680 keV.

Beam Parameters