Exploring cesium properties internal to the LANSCE H- ion source using resonant absorption spectroscopy

The Los Alamos Neutron Science Center (LANSCE) H- ion source has provided stable output for decades of LANL mission needs, but its maximum beam output has remained the same at & SIM;15 mA. A roadblock to improving beam output has been a lack of thorough understanding of the internal mechanisms of LANSCE H- ion source. The LANSCE H- Ion Source Laser Diagnostic Stand (HLDS) was recently built and commissioned to explore these internal mechanisms using laser absorption techniques, to measure and diagnose dynamic H- and cesium densities. The cesium density probe is based on resonant absorption of a continuous wave diode laser tuned though the D2 line of cesium (& SIM;852 nm). The diagnostic capabilities of HLDS will be reviewed, and measurements using the cesium laser diagnostic will be presented.