Near term plans for LTX - β

LTX-β began operations in the summer of 2018, and has now operated without a vent or other major modifications for over four years, through the end of FY2022, which may be a record for any tokamak. A vent is planned for early FY23, to service internal components of the tokamak. The vent will also incorporate a number of changes and modest upgrades to improve operations. Modifications will include new porting for the neutral beam (added as part of the upgrade to LTX-β) to increase the tangency radius, which is expected to reduce the first orbit fast ion loss fraction, and improve beam coupling at higher injection energy. A new set of instrumented beam dumps and scrapers will be installed, to relocate and replace the existing beam dumps. The high voltage power supply for the neutral beam will also be upgraded, to increase the pulse length by 3×. Separate collection optics and APD-based polychromators for the Thomson scattering system, which view to the high field side of the plasma axis, were installed in 2021 – 2022, and improvements to this system planned for the vent include a more extensive viewing dump to reduce stray light. We are also investigating the implementation of a second pass for the laser beam to improve the signal level. A new remotely actuated lithium deposition system will be installed. LTX-β is fueled by a combination of high field side gas puffing, with a low field side supersonic gas injector. An additional high field side nozzle will be added during this vent. These modifications, along with near term research plans, will be discussed.