  Photomultiplier tubes (PMTs) are traditionally an integral part of large
underground experiments as they measure the light emission from particle
interactions within the enclosed detection media. The BUTTON experiment will
utilise around 100 PMTs to measure the response of different media suitable for
rare event searches. A subset of low-radioactivity 10-inch Hamamatsu R7081 PMTs
were tested, characterised, and compared to manufacture certification. This
manuscript describes the laboratory tests and analysis of gain, peak-to-valley
ratio and dark rate of the PMTs to give an understanding of the charge
response, signal-to-noise ratio and dark noise background as an acceptance test
of the suitability of these PMTs for water-based detectors. Following the
evaluation of these tests, the PMT performance agreed with the manufacturer
specifications. These results are imperative for modeling the PMT response in
detector simulations and providing confidence in the performance of the devices
once installed in the detector underground.
