Initial LTX-β Plasma Facing Component and Scrape-Off Layer Characterization

Lithium coatings on high-Z PFCs in the Lithium Tokamak eXperiment (LTX) led to flat temperature profiles. The flat temperature profiles were observed along with a broad collisionless Scrape-Off Layer (SOL). Additionally, an in-vacuo X-Ray Photoelectron Spectroscopy (XPS) system established that evaporatively deposited lithium coatings oxidized, while retaining the ability to achieve flat temperature profiles. LTX continued to observe performance comparable to freshly deposited lithium coatings with partially oxidized lithium plasma facing components (PFCs). Theory attributes flat temperature profiles to low recycling walls. The presence of oxidized lithium, however, raises questions regarding the mechanism of hydrogen retention in LTX. To investigate these questions, LTX-β upgrade will be equipped with a Sample Exposure Probe (SEP) for in-vacuo XPS analysis with higher resolution, along with new SOL particle density and energy diagnostics. We will present on the status of development of these diagnostics, and include some preliminary results characterizing the SOL and the LTX-β PFCs using them.