Speaker
Description
The sPHENIX experiment, under construction at Brookhaven National Lab’s Relativistic Heavy Ion Collider, will take first data in 2023, beginning a broad experimental program that will study the emergent properties of QCD in the Quark Gluon Plasma, the structure of jets, and the spin structure of nucleons. The observables that enable these studies require precise tracking provided by three tracking detectors: The innermost MAPS-based vertex detector, a high time-resolution silicon strip detector, and a compact time projection chamber (TPC) with continuous readout through a GEM-based avalanche stage. To meet the needs of the physics program, distortions of the trajectories of drift electrons in the TPC, due to magnetic field and spacecharge effects, must be accurately measured and corrected. In addition to monitoring time-averaged distortions through particle tracks, the TPC has several dedicated components to constrain the distortions. The charge arriving at the readout is digitized and summed into a 'digital current', which monitors the spacecharge flowing back into the volume, and two laser calibration systems monitor the static and short-timescale components of the distortions directly. This poster will discuss the expected magnitudes and structures of the distortions, the systems that monitor those distortions, and the derivation of the necessary corrections; details of how these corrections are implemented in tracking are described in a separate poster.
