Recent beam performance tests and source diagnostics on the LANSCE <i>H</i> ^- ion source

Abstract The filament arc driven plasma, cesiated surface conversion H - ion source used at the Los Alamos Neutron Science Center (LANSCE) has a long legacy of providing reliable beam to the LANSCE user program. Despite the long history of beam delivery, there remains valuable opportunity for fundamental diagnostic studies, and subsequent operational improvements of the LANSCE H - ion source based on these diagnostics. The LANSCE H - Ion Source Laser Diagnostic Stand (HLDS) was built to study these fundamental diagnostics. HLDS is currently capable of measuring cesium density/temperature via Tunable Diode Laser Absorption Spectroscopy (TDLAS), and plasma properties related to the H α Balmer line via Optical Emission Spectroscopy (OES) and TDLAS. An update will be given on measurements taken using these diagnostic tools. In particular, detailed focus will be given on how results from the Cs TDLAS diagnostic was used to mitigate arc and converter transients due to Cs instabilities, to study hastening the Cs conditioning process, and a first look at continuous Cs density monitoring during Cs conditioning and operation. Finally, a first look and interpretation of the commissioned data taken of the H α Balmer line via OES and TDLAS will be discussed.