Speaker
Description
The Circular Electron Positron Colliders (FCCee and CEPC) were proposed as the Higgs and Z operation in High Energy Physics communities. In the tracker detector concept, as well as in comparable detector designs, the baseline detector design features a high-precision (approximately 100 μm) spatial resolution Time Projection Chamber (TPC) as the main tracking device surround a 3.0T solenoid field. The TPC is required to provide a standalone momentum resolution of 10⁻⁴ (GeV/c)⁻¹, and the physics requirement of Particle Indentification (PID) resolution should be reached less than 3%. TPC performance is satisfactory in Higgs mode, but high luminosity Z pole running poses substantial technical challenges requiring rigorous evaluation of feasibility and mitigation strategies.
Based on the latest MDI background simulation data, we have assessed ion-induced space charge effects in the TPC under Z-pole running conditions. The updated estimation at FCC-ee Week 2026 revealed that synchrotron radiation background at Tera-Z is ~3 orders of magnitude higher than incoherent pair creation, posing extreme challenges for all detectors. Our full simulation chain shows maximum space charge densities of 1.7 nC/m³ (Higgs) and 3.3 nC/m³ (low-lumi Z), causing ~50% momentum resolution degradation at high pT for TPC-only tracking, improved to ~20% with silicon trackers. Crucially, MDI optimization—aluminum beampipe and tungsten shielding—reduces photon flux by ~85%, suppressing space charge below 0.8 nC/m³ and controlling resolution degradation under 10%, confirming TPC feasibility through collaborative MDI optimization. In this talk, the feasibility and update progress of high precision TPC as the main track detector for e+ e− collider will be presented. TPC detection aims the good separation power with the cluster counting to be considered and the simulation results of the pad/pixelated TPC technology for e+ e− collider will be given. Compared with the pad readout using the simulation, the high granularity readout TPC option (500μm × 500μm) will obtain the better spatial resolution of single electrons, the very high detection efficiency in excellent tracking and good PID performance (less than 3σ).