Speaker
Description
The Tokai-to-Kamiokande (T2K) experiment is a long-baseline neutrino experiment based in Japan. T2K obtained results that disfavour CP conservation with a 90% confidence level so far. The (anti)neutrino beam created at J-PARC is characterised at the near detector before measuring the oscillated spectrum using the Super-Kamiokande detector 296 km away. Toward more precise measurements of neutrino oscillations, T2K started operation of the fully upgraded near detector in 2024 to further reeduce major systematic uncertainties on neutrino-nucleus interactions. The upstream part of the near detector ND280 was replaced with three new detectors: the Super Fine-Grained Detector (SuperFGD), two High-Angle Time Projection Chambers (HATs), and six Time of Flight detectors (ToF). The SuperFGD is a target tracker which consists of about two million 1 cm3 plastic scintillator cubes packed in an approximate 2 m x 2 m x 0.6 m configuration. Scintillation light from the cubes is read out by around 56,000 channels from three directions through wavelength-shifting fibres and photosensors. It provides 3D track reconstruction, 4pi angular acceptance, calorimetry, and detection capability of neutrons and low momentum protons. We report the SuperFGD design, construction, operation status and detector performance.
