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Abstract

The XENON Dark Matter Search project aims for the direct detection of dark matter.
Using a total mass of 3.3 tonnes of liquid xenon as target material for scattering events
by weakly interacting massive particles (WIMPs), the XENON1T detector has set worldleading
exclusion limits on the spin-independent WIMP-nucleon interaction cross-section.
In the first part of thesis, the data acquired in more than one year of XENON1T operation
is investigated for a very specific signature for dark matter: The annual modulation of
the expected dark matter rate, caused by the Earth’s movement through our galactic dark
matter halo. The second part of this thesis is focussed on the next phase of the XENON
project. With an increased target mass of in total 8.4 tonnes of xenon, its aim is to increase
the sensitivity for direct dark matter detection by one order of magnitude to probe new
regions of the parameter space. The scintillation light induced in liquid or gaseous xenon
by particle interactions in XENONnT will be detected with 494 photomultiplier tubes
(PMTs). The Hamamatsu R11410 tube has been chosen for its high quantum efficiency and
low intrinsic radioactivity to maximize the detector’s sensitivity. In the scope of the thesis,
the characteristics and performance of the PMTs for XENONnT have been studied and
tested extensively. The general testing procedures and the results of the testing campaign
will be presented here.