KM3NeT is a distributed neutrino research infrastructure in
the Mediterranean Sea. KM3NeT/ARCA is a high-energy neutrino
telescope, dedicated to the search for extraterrestrial neutrino
sources in the TeV-PeV range.
One major goal is the identification of the sources of the neutrino flux recently discovered by IceCube.
Furthermore, KM3NeT/ARCA is optimised to study Galactic neutrino point sources.
The analysis of the flavour composition of astrophysical neutrinos
arriving at Earth can shed light on the production mechanisms of
these neutrinos inside their astrophysical sources. The distinction
between different neutrino flavours is only possible on a
statistical basis and a method called ``spectral fitting'' is
employed to this end. In order to estimate the sensitivity of
KM3NeT/ARCA to the flavour composition using this method, spectra
obtained from Monte-Carlo-based pseudo-data samples are compared to
expectations from neutrino flux models for signal and background.
To increase the power of the spectral fitting procedure, the event
sample is separated into multiple subsamples according to their
event type. Therefore, an artificial neural network is used to
discriminate between five target types: double bang events, cascades
and three different track-like event types.