Speaker
Description
The T2K experiment has recently completed the upgrade of its off-axis near detector, ND280. Two new gaseous High-Angle Time Projection Chambers (HA-TPCs) have been installed above and below the highly segmented scintillator active target, the Super-Fine Grained Detector (SFGD), to precisely track particles emitted at large angles with respect to the beam direction. The two new gaseous detectors feature innovative resistive Micromegas technology, and a field cage composed of thin composite walls. This contribution will provide a detailed description of the new components of the chambers, including the gas system, gas monitoring chambers, and data acquisition system. Additionally, the recently published performance results of the HA-TPCs [1] will be presented including the results of extensive testing using both neutrino beams and cosmic rays, with comparisons between data and Monte Carlo simulations. The new detectors achieve improved spatial resolution and enhanced particle identification capabilities which are crucial for the precision goals of the T2K experiment.
[1] https://doi.org/10.1016/j.nima.2026.171527
