Towards Baikal-Top: Feasibility study of an onshore detector system for the joint registration of EAS with Baikal-GVD

TL;DR

This study explores the feasibility of an onshore detector system near Lake Baikal to jointly register high-energy EAS with Baikal-GVD, aiming to improve understanding of muons in EAS and calibrate neutrino measurements.

Contribution

It presents a feasibility analysis and simulation results for an onshore detector array to detect EAS in coordination with Baikal-GVD, including optimal area estimates and detection capabilities.

Findings

Simultaneous EAS registration is feasible for zenith angles around 76 degrees.

The detector can estimate high-energy muon content in EAS.

Estimated event rates for joint detection are provided for various detector sizes.

Abstract

We study the possibility of registering high-energy extensive air showers (EAS) by the onshore detector facility simultaneously with the trigger of the Baikal-GVD neutrino telescope. The location of the surface detector array on the shore of Lake Baikal is motivated by the fact that permanent placement of detectors on the surface of the lake is challenging. Within the given geometry, simultaneous registration is possible for EAS with a zenith angle of about 76 degrees within the limited solid angle. The corresponding inclined EAS are dominated by muons and significantly attenuated. The installation will make it possible to obtain an estimate of the number of high-energy muons in EAS. This, subsequently, would make it possible to verify EAS modeling and calculations of the atmospheric neutrino flux. The detector may also be used for cross-calibration of energy and direction measurements by the neutrino telescope. We use the CORSIKA program to simulate the registration of EAS on the shore close to the Baikal-GVD. The propagation of ultra-high energy muons produced by EAS through 3.5 km of water and their registration by Baikal-GVD is simulated using the PROPOSAL package. We calculate the minimal total area of the onshore detectors suitable for several cosmic ray energy thresholds, starting from 1 PeV. The report presents estimates of the number of events jointly registered by the onshore installation and the Baikal-GVD the EAS registration detector systems with different areas.