Speaker
Description
In the PandaX-4T experiment, R11410 photomultiplier tubes (PMTs) account for approximately 47% of the detector’s material-induced electron recoil background, representing a major limitation in background reduction. As future liquid xenon detectors, such as the proposed PandaX-20T with a 20-tonne target, aim to reach sensitivities $3.5×10^{-49} cm^{2}$ at $40 GeV/c^2$ near the irreducible neutrino floor, further suppression of internal backgrounds underscores the need for improved photon sensors.
To address this challenge, we present the development of a low-radioactivity, multi-channel 2-inch PMT (R12699), co-developed with Hamamatsu. Radiopurity screening shows significantly reduced $^{60}$Co and U/Th chain activities compared to R11410. Cryogenic characterization at -100℃ demonstrates stable operation with a gain of $4.2×10^6$, a dark count rate of 2.5 Hz/channel, and an afterpulse probability of 0.5%. These results position R12699 as a promising candidate for future xenon-based rare event searches.
