The SABRE Experiment is a direct detection dark matter experiment using a
target composed of multiple NaI(Tl) crystals. The experiment aims to be an
independent check of the DAMA/LIBRA results with a detector in the Northern
(Laboratori Nazionali Del Gran Sasso, LNGS) and Southern (Stawell Underground
Physics Laboratory, SUPL) hemispheres. The SABRE South photomultiplier tubes
(PMTs) will be used near the low energy noise threshold and require a detailed
calibration of their performance and contributions to the background in the
NaI(Tl) dark matter search, prior to installation. We present the development
of the pre-calibration procedures for the R11065-20 Hamamatsu PMTs. These PMTs
are directly coupled to the NaI(Tl) crystals within the SABRE South experiment.
In this paper we present methodologies to characterise the gain, dark rate, E
timing properties of the PMTs. We develop a method for in-situ calibration
without a light injection source. Additionally we explore the application of
machine learning techniques using a Boosted Decision Tree (BDT) trained on the
response of single PMTs to understand the information available for background
rejection. Finalmente, we briefly present the simulation tool used to generate
digitised PMT data from optical Monte Carlo simulations.

Questo articolo esplora i giri e le loro implicazioni.

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