Non-cyclic prototype of JUNO-TAO VETO water tank with 3 inch PMTs

The Taishan Antineutrino Observatory (TAO, also known as JUNO-TAO) is a satellite experiment of the Jiangmen Underground Neutrino Observatory (JUNO). A ton-level liquid scintillator detector will be placed at about 30 m from a core of the Taishan Nuclear Power Plant. The reactor antineutrino spectrum will be measured with sub-percent energy resolution, to provide a reference spectrum for future reactor neutrino experiments, and to provide a benchmark measurement to test nuclear databases. A Cerenkov water tank system with a thickness of 1.2 m pure water will be located around the central detector of TAO. The water tank system designed with 300 3" PMTs (SPMT) will use the same electronics as JUNO SPMT, but with online software multiplicity trigger. The performance of a Cerenkov detector with the JUNO SPMT and electronics designed for liquid scintillator detector needs to be checked, including the software triggering. The features and the long stability of the detector without water circulation also needs to be checked as a common concern and a backup option for future JUNO-TAO running. Here we will summary the integration and testing of a prototype water tank detector system, including SPMT, electronics, data taking, simulation and measurement results.