Photomultiplier tubes (PMTs) with large-area cathodes are
increasingly being used in cosmic-ray experiments to enhance
detection efficiency. The optical modules (OMs) of the High-Energy
Underwater Neutrino Telescope (HUNT) have employed a brand new N6205
20-inch microchannel plate photomultiplier tube (MCP-PMT) developed
by the North Night Vision Science & Technology (Nanjing) Research
Institute Co. Ltd. (NNVT). In order to make the 20-inch PMT fit into
the 23-inch diameter pressure-resistant glass sphere, NNVT improved
the internal structure of PMT and shortened the height of PMT by
more than 10 cm. The first batch of these PMTs has been delivered
for preliminary research work. This paper describes a specific PMT
testing platform built for the first batch of 15 MCP-PMTs, and some
performance parameters of PMT, such as peak-to-valley ratio, TTS and
nonliniearity, are measured. The measurement results show that the
new PMT still has good performance and can meet the requirements of
HUNT project.