Correcting Static Distortions in the sPHENIX TPC with a Remotely Steerable Laser System

The central tracking detector of the sPHENIX experiment is a compact, gaseous Time Projection Chamber (TPC). The TPC aims to achieve an azimuthal position resolution <150 um with high data throughput in order to accomplish the physics goals of sPHENIX (e.g. measuring the differential suppression of Upsilon (Υ) mass states). To reach this precision, several independent calibration mechanisms are used to correct distortions in apparent particle trajectories due to nonuniformity in the E and B fields in the detector. These distortions have both dynamic components, generated from space charge and changing environmental, beam, and detector conditions, as well as static components arising from inhomogeneities in the solenoid and drift fields. The static distortions are probed with a steerable laser system capable of ionizing the gas in the TPC volume. The reconstruction of these known, straight tracks provides information about the total distortions throughout the detector. In this talk, we discuss the mechanics, electronics, and software that comprise this system's novel design, as well as the ongoing work to apply static distortion corrections to sPHENIX TPC data.