T2K is a long-baseline neutrino experiment that aims to investigate the CP violation in the neutrino sector. An upgrade of the ND280, which is one of the T2K near detectors, is in progress. The active target detector of the upgraded ND280 is a segmented highly granular plastic scintillation detector (SuperFGD) consisting of about two million cubes. About sixty thousand silicon photo-multipliers (SiPMs) coupled with wavelength shifting fibers are used for light readout. The fibers go through the scintillator cubes along the orthogonal three directions. We developed a new system based on LEDs and notched light guide plates for in-situ calibration of SuperFGD. The developed system can distribute LED light for SiPMs simultaneously with high uniformity and be used for gain calibration and stability monitor of the signal readout. In addition, it can fit in the confined space of the SuperFGD due to its thin structure. We will present the design and the performance of the calibration system.
|TIPP2020 abstract resubmission?||Yes, this would have been presented at TIPP2020.|