Design and Commissioning of the sPHENIX Time Projection Chamber

The Time Projection Chamber (TPC) is the main tracking detector in sPHENIX, a new experiment at the Relativistic Heavy Ion Collider (RHIC). Charged particles which pass through the TPC ionize the gas. The ionization electrons drift to the endcap under a uniform electric field, with the transverse position of the ionization site given by the readout pad they strike, and its z position given by the time they arrive. These hits are then clustered together in order to track particles and determine their momenta. Commissioning of the sPHENIX TPC began in May 2023 using cosmic rays, lasers, and Au+Au collisions both with and without the magnetic field. The Front End Electronics are performing well with low noise and high live rates. This talk will discuss the design of the sPHENIX TPC and the commissioning progress in the first run and future work towards the first physics measurements.