Development of large-aperture hybrid avalanche photo-detector

This paper reports on the R&D status of a large-aperture Hybrid Avalanche Photo-Detector (HAPD). We have developed a 13-inch aperture HAPD and its readout system. The HAPD is a photo detector expected to replace the photomultiplier tube (PMT) in next-generation next-generation imaging water Cherenkov detectors such as Hyper Kamiokande. We will present the recent progress made in readout system development, new compact high-voltage power supply, and a new 8-inch aperture HAPD.