  Coherent elastic neutrino-nucleus scattering (CEvNS) opens new approaches for
the search of new physics beyond the Standard Model. The NUCLEUS experiment
aims to use the intense antineutrino flux produced from nuclear reactor cores
to perform measurements of the CEvNS cross-section via gram-scale ultra-low
threshold cryogenic detectors. A common problem with low threshold detectors is
the calibration, since most radioactive sources tend to saturate the dynamical
range of the sensors. In this dissertation, a photon-statistic based optical
calibration setup has been developed and tested using detectors from the
BULLKID R&D project. Both the developed hardware setup and the relative control
software allow to automatically perform a full calibration of an array of
detectors. During the development of this work, the DIANA analysis framework,
developed for the CUORE experiment, has been compatibilized with the NUCLEUS
DAQ and a new automatic analysis protocol was developed using the data from the
NUCLEUS prototype runs. This protocol proved to be accurate at reproducing the
results obtained via a model dependent study performed with an almost event by
event inspection that was carried out in the early stages of NUCLEUS.
Particular focus was given to the development of an event reconstruction
procedure used to measure the energy of events that lie outside the linear
response region of the detector. The last activity done for the NUCLEUS
experiment was to develop a python based toolkit for the study of the discovery
potential of the experiment. This toolkit was originally developed in the early
stages of NUCLEUS by J.Rothe and has been intensely upgraded during the work
presented in this thesis, in order to deal with different types of statistical
checks and procedures.
