LINAC2026 - 33rd Linear Accelerator Conference

Mitigation of high voltage arc-downs of the LANSCE H- 80 keV pre-injector column

Not scheduled

2h

Daejeon Convention Center

Poster Presentation MC3.A01: Industrial and medical accelerators Poster Session

Speaker

Adler Weismantel (Los Alamos National Laboratory)

Description

The LANSCE H- beam ultimately reaches 800 MeV to serve its user programs. The H- beam originates in a filament arc-driven plasma cesiated-surface-conversion H- ion source, and is initially accelerated to 80 kV via a three-stage accelerating column. A prime source of H- beam instabilities at LANSCE come from high voltage arc-downs of the 80 keV Column. These arc downs are primarily due to the cesium in the H- source, which can quench the hydrogen plasma, or over-cesiate and short the converter surface. Excessive 80 kV arc-downs lead to failure on the 80 kV column components, further increasing downtime.
Recent upgrades were made to mitigate these arc-downs, and to protect the 80 kV column components. Mitigation of source-based arc-downs involves current limiting the converter with a high-power resistor, and adding FPGA based fast electronics that turns off the beam gate on over-currents on the plasma or converter current. Equipment protection upgrades involve implementing block/clamp diodes for power supply protection, and calibrated spark gaps to ensure proper arc-downs to ground. The design, implementation and results of these upgrades will be discussed.