Ion Source Development at the SNS

The US Spallation Neutron Source (SNS) has recently begun producing neutrons and is currently on track to becoming a world‐leading facility for material science based on neutron scattering. The facility is comprised of an H− ion source, a linear accelerator, an accumulator ring, a liquid‐Hg target and a suite of neutron scattering instruments. Over the next several years the average H− current from the ion source will be increased in order to meet the baseline facility requirement of providing 1.4 MW of beam‐power to the target and the SNS power upgrade power requirement of 2+ MW on target. Meeting the latter goal will require H− currents of 70–100 mA with an RMS emittance of 0.20–0.35 π mm mrad and a ∼7% duty‐factor. To date, the RF‐driven‐multicusp SNS ion source has only been able to demonstrate sustained operation at 33 mA of beam current at a ∼7% duty‐factor. This report details our efforts to develop variations of the current ion source which can meet these requirements. Designs and experimental res...