New developements in high precision, high particle density tracking with time projection chambers

Over the past few years, time projection chambers have become a major detector option for tracking and particle identification in ultrarelativistic heavy ion physics. This is particularly apparent in the forthcoming big experiments at the CERN SPS (NA49) and at the RHIC (STAR) and LHC (ALICE) colliders. For these difficult experimental environments (extremely high track densities, space charge and rate limitations, high requirements on space and double track resolution) the classic TPC concept has to be pushed to new limits. We will report on new developements in the context of the NA49 and ALICE experiments, especially concerning ultralight field cage structures, low density gas mixtures, improved space and double track resolution, alternative readout chamber concepts, and new electronics and information transmission schemes.