The SuperFGD for the upgraded T2K near detector — Operation and performance

The SuperFGD detector, part of the near detector upgrade for the T2K experiment, was designed to enhance the understanding of neutrino-nucleus interactions and reduce systematic uncertainties in neutrino oscillation measurements. It consists of approximately 2 million plastic scintillator cubes, with wavelength-shifting fibers and SiPMs for readout in three orthogonal directions, enabling precise 3D particle tracking and providing a 2-ton target mass for neutrino interactions. The construction, installation, and first beam commissioning, conducted in 2023–2024, demonstrated excellent detector performance with stable data acquisition and precise calibration. Analyses are ongoing to precisely measure neutrino-nucleus interactions, which will help reduce systematic uncertainties in neutrino oscillation measurements.