Observation of the temperature and barometric effects on the cosmic muon flux by the DANSS detector

TL;DR

This study measures how temperature and atmospheric pressure influence cosmic muon flux at different depths near a nuclear reactor, using the DANSS detector over nearly four years.

Contribution

It provides detailed measurements of temperature and barometric effects on muon flux at multiple depths and angles, enhancing understanding of environmental influences on cosmic ray detection.

Findings

Muon flux varies with temperature and pressure at different depths.

Correlation coefficients differ for vertical and horizontal muons.

Data collected over four years enables long-term analysis.

Abstract

The DANSS detector is located directly below a commercial reactor core at the Kalinin Nuclear Power Plant. Such a position provides an overburden about 50 m.w.e. in vertical direction. In terms of the cosmic rays it occupies an intermediate position between surface and underground detectors. The sensitive volume of the detector is a cubic meter of plastic scintillator with fine segmentation and combined PMT and SiPM readout, surrounded by multilayer passive and active shielding. The detector can reconstruct muon tracks passing through its sensitive volume. The main physics goal of the DANSS experiment implies the antineutrino spectra measurements at various distances from the source. This is achieved by means of a lifting platform so that the data is taken in three positions - 10.9, 11.9 and 12.9 meters from the reactor core. The muon data were collected for nearly four calendar years. The overburden parameters $\langle E_{thr}\cos\theta \rangle$ and $\langle E_{thr} \rangle$, as well as the temperature and barometric correlation coefficients are evaluated separately for the three detector positions and, in each position, in three ranges of the zenith angle - for nearly vertical muons with $\cos\theta>0.9$, for nearly horizontal muons with $\cos\theta<0.36$, and for the whole upper hemisphere.