SNS Front End Systems -
Medium Energy Beam Transport (MEBT)
Lawrence Berkeley National Laboratory (LBNL) is presently designing
and building the 2.5 MeV injector for the Spallation Neutron Source (SNS).
The injector includes a medium-energy beam transport (MEBT) which carries
the 2.5 MeV, 52 mA H- beam from the radio frequency quadrupole (RFQ) to
the drift tube linac (DTL) through a series of 14 electromagnetic quadrupoles,
four rebuncher cavities, and a traveling wave chopping system. The
beamline contains numerous diagnostic devices, including stripline beam
position and phase monitors (BPM), toroid beam current monitors (BCM),
and beam profile monitors. Components are mounted on three rafts
that are separately supported and aligned. The large number of beam
transport and diagnostic components contained in the 3.5 meter-long beamline
necessitates an unusually compact mechanical design.