The LANSCE (Los Alamos Neutron Science CEnter) accelerator complex is currently driven by a filament-powered, biased converter-type H- ion source that operates at a high plasma duty factor of 10%. This is the world’s highest duty factor for pulsed high-current H- accelerators using only ~2.2 sccm of H2 (standard cubic centimeter per minute). The ion source needs to be replaced every 4 weeks with a ~4 day startup phase. The measured negative beam current of 16-18 mA falls below the desired 21 mA acceptance of the LANCSE accelerator especially since the beam contains several mA of electrons.
On the other hand the SNS (Spallation Neutron Source) RF-driven, H- ion source injects ~50 mA of H- beam into the SNS accelerator at 60 Hz with a 6% duty factor and an availability of ~99.9%, but requiring ~30 sccm of H2. Up to 7 A·hrs of H- have been produced during the up to 14-week long service cycles, which is an unprecedented lifetime for small emittance, high-current pulsed H- ion sources. The SNS source also features unprecedented low Cs consumption and can be installed and started up in <10 h.
LANSCE and SNS are considering the use of a SNS H- ion source on the LANSCE accelerator because it should a) decrease the source replacement time by a factor of ~8, b) increase source lifetime by a factor of 2-3, and c) increase the accelerator power by up to ~40%. However, this is a significant challenge as characteristics and normal operating regimes are drastically different. This talk will report on operating the SNS source with a 10% duty factor and adapting the small-diameter, small-emittance SNS beam to the 2-solenoid magnetic LANSCE LEBT (low- energy beam transport).
This work is performed at Los Alamos National Laboratory under contract DE-AC52-06NA25396 and at Oak Ridge National Laboratory under contract DE-AC05-00OR22725 and for the U.S. Department of Energy.
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