the main part of the paper, are the following:
•Representation of Baikal-GVD’s data in a form that makes direct use of the causal
structure of the events;
•Introduction of multiplicative Gaussian noise for proper simulation of the fluctuations
of OMs readings;
•The use of a custom loss function that reduces time residuals of the hits identified as
signal ones by the neural network;
•Neural network is insensitive to the auxiliary hits, which are introduced to make data
representation uniform;
•Compared to the noise suppression algorithms developed by the Baikal-GVD collab-
oration [1,7], our neural network has better metrics and allows for a much faster
data analysis.
The developed method can also be readily extended to process the multi-cluster data.
The paper is structured as follows. In section 2we describe the Monte-Carlo simula-
tions of Baikal-GVD’s data. In section 3and appendix Adata representation and neural
network’s architecture are discussed. The results, including comparison with non-machine
learning methods, are presented in section 4. Finally, section 5concludes the paper.
2 Monte-Carlo simulations
Simulation of the data is performed via the Monte-Carlo method. Two types of in-
coming particles are considered: 1) muon neutrinos arriving from under the horizon, and
2) bundles of muons originating from the cosmic air showers. The energy spectrum and
incoming directions of arriving particles are chosen to coincide with the ones expected in
the experiment, see [8,9] for details. The procedure takes into account photon scattering
in Baikal’s water and full simulation of cosmic air showers’ evolution using QGSJET II-03
[10] and CORSIKA [11]. The noise rate and charge distribution are simulated so as to
mimic the experimentally expected detector conditions.
The triggering condition for identifying an event is the following: two adjacent OMs,
within the 100 ns time window, register signals that are at least 4.5 and 1.5 p.e. If this
condition is fulfilled, the data from all OMs exceeding the signal-level threshold (0.3 p.e.)
is collected for further analysis.
Registered signals (waveforms) are approximated by discrete hits (pulses). Each of the
hits is characterized by the following physical observables:
1. Time at which the hit was registered;
2. Integral charge (in p.e.) registered by OM;
3. Maximal amplitude of the registered signal.
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