An H- surface plasma source for the ESS storage ring

Abstract

Abstract For H- charge exchange (stripping) injection to European Spallation Source (ESS) storage ring it is necessary to have H- ion source with a current of ∼90 mA, pulses duration 3 ms, and repetition of 14 Hz (duty factor ∼4%) extendable to repetition up to 28 Hz (df ∼8%). Magnetron surface plasma H- source (SPS) with cesiation and active cathode and anode cooling is one of the possible solutions. Brookhaven National Laboratory (BNL) magnetron SPS can produce H- beam current of ∼100 mA at ∼2 kW discharge power and can operate up to a duty factor of ∼1% (average power ∼14 W) without the active cooling. With active cathode and anode cooling it is possible to increase average discharge power up to 140 W(df 8%).For the delivery of the beam to Radio Frequency Quadrupole (RFQ) it is possible to use a short electrostatic Low Energy Beam Transport (LEBT) as in Spallation Neutron Source (SNS).