Recent Performance of and Plasma Outage Studies with the SNS H- Source
SNS ramps to higher power levels that can be sustained with high availability. The goal is 1.4 MW despite a compromised RFQ, which requires higher RF power than design levels to approach the nominal beam transmission. Unfortunately at higher power the RFQ often loses its thermal stability, a problem apparently enhanced by beam losses and high influxes of hydrogen. Delivering as much H- beam as possible with the least amount of hydrogen led to plasma outages. The root cause is the dense 1-ms long ~55-kW 2-MHz plasma pulses reflecting ~90% of the continuous ~300W, 13-MHz power, which was mitigated with a 4-ms filter for the reflected power signal and an outage resistant, slightly-detuned 13-MHz match. Lowering the H2 also increased the H- beam current to ~55 mA, and increased the transmission by ~7%.
- Publication Date:
- OSTI Identifier:
- DOE Contract Number:
- Resource Type:
- Resource Relation:
- Conference: International Conference on Ion Sources, New York, NY, USA, 20150823, 20150828
- Research Org:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source
- Sponsoring Org:
- USDOE Office of Science (SC)
- Country of Publication:
- United States
- H- ion source; ion source; radio frequency; plasma; source lifetime
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