SuperNEMO is a neutrinoless double beta decay (0νββ) experiment with an expected half-life
sensitivity in excess of 1026 years for the isotope 82Se. This corresponds to an effective Majorana
neutrino mass of 40 – 100 meV. The unique tracker-calorimeter technique used in the SuperNEMO
experiment provides the ability to reconstruct the full event topology of almost any double beta
decaying isotope, producing “smoking gun” evidence for the 0νββ process and potentially allowing
the underlying physical mechanism behind neutrinoless double beta decay to be disentangled. Currently the SuperNEMO demonstrator module is being commissioned and is expected to achieve a
half-life sensitivity of 6.5 × 1024 years for the 0νββ of 82Se.

A key feature of the SuperNEMO design is the magnetic field that can be used to reject backgrounds originating from sources outside of the detector tracking volume. However, the application
of a magnetic field reduces the efficiency of detecting the ββ signal. This thesis presents the development and implementation of a comparative analysis of the detector sensitivity to neutrinoless
double beta decay, in the presence of different magnetic field configurations. The magnetic coil for
the SuperNEMO demonstrator module has been recently installed and is expected to be activated
in due course. The performance of the detector, using three alternative magnetic field configurations, has been considered in this work, including; a uniform field with a constant field strength of
25 G, no field with zero magnetic flux and a realistic field which is a representation of the expected
magnetic field taking into account the design of the detector.

The neutrinoless double beta decay half-life sensitivity for 82Se has been estimated for three
alternative magnetic field configurations using an analysis based on event counting in an optimised
energy window. The signal (0νββ) detection efficiency and total background contributions from
internal, radon and external sources were considered. A maximum half-life sensitivity limit of 1.4
× 1024 years at 90% CL was achieved for the no field scenario with a region of interest between
2.75 and 2.95 MeV. The performance of the no field scenario was only marginally greater than
the uniform and realistic fields (1.2 and 1.0 × 1024 years respectively) under the same conditions.
Implications of these findings on the SuperNEMO demonstrator physics run plans commencing 2022
are discussed.