Recent Performance of and Plasma Outage Studies with the SNS H- Source

Conference · Fri Jan 01 00:00:00 EST 2016

OSTI ID:1286897

Stockli, Martin P ^[1]; Han, Baoxi ^[1]; Murray, Jr, S N ^[1]; Pennisi, Terry R ^[1]; Piller, Chip ^[1]; Santana, Manuel ^[1]; Welton, Robert F ^[1]

---

1. ORNL

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%.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1286897
• Resource Relation: Conference: International Conference on Ion Sources, New York, NY, USA, 20150823, 20150828
• Country of Publication: United States
• Language: English

Related Subjects

H- ion source
ion source
radio frequency
plasma
source lifetime