|TUPTS009||Operating the SNS RF H− Ion Source with a 10% Duty Factor||1951|
Funding: This work was performed at Oak Ridge National Laboratory under contract DE-AC05-00OR22725 and at Los Alamos National Laboratory under contract DE-AC52-06NA25396 for the U.S. Department of Energy.
The SNS (Spallation Neutron Source) (radio-frequency) RF-driven, H− ion source injects ~50 mA of H− beam into the SNS accelerator at 60 Hz with a 6% duty factor. It injects up to 7 A·hrs of H− ions during its ~14-week service cycles, which is an unprecedented lifetime for small-emittance, high-current pulsed H− ion sources. The SNS source also features unprecedented low cesium consumption and can be installed and started up in <10 h. Presently, the LANSCE (Los Alamos Neutron Science CEnter) accelerator complex in Los Alamos is fed by a filament-driven, biased converter-type H− source that operates with a high plasma duty factor of 10%. It 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 LANSCE’s accelerator especially since the beam contains several mA of electrons. LANSCE and SNS are exploring the possibility of using the SNS RF H− source at LANSCE to increase the H− beam current and the ion source lifetime while decreasing the startup time. For this purpose, the SNS H− source has been tested at a 10% duty factor by operating it at 120 Hz with 840 µs plasma pulses generated with ~30 kW of 2 MHz RF power, and extracting ~25 mA around-the-clock for 28 days. This, and additional tests and other considerations are discussed in this paper.
|DOI •||reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPTS009|
|About •||paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019|
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