Enhancing Water Cherenkov Detector Arrays through multiPMT Modules

Abstract

Water Cherenkov Detectors (WCDs) are pivotal in various scientific fields, including neutrino physics, gamma-ray astronomy, and cosmic-ray research. The detection sensitivity and precision of these detectors crucially rely on photomultiplier tubes (PMTs) to capture Cherenkov radiation produced by charged particles moving faster than the speed of light in water. In recent years, employing multiPMT modules has emerged as a promising strategy to enhance large volume water and ice Cherenkov detector performance. In this work we explore the use of a multiPMT module in small WCD units, arranged in arrays as typically used to detect Extensive Air Showers (EAS). We outline a possible configuration and present the advantages it can offer for data analysis, as demonstrated through dedicated simulations. We investigate the potential of multiPMTs in capturing the features of the Cherenkov light distribution originated by single muons and discuss its possible application for muon tagging in WCD arrays.

Figures (10)

• Figure 1: Sketch of the proposed multiPMT module. The semi-spherical vessel hosts seven 3-inch PMTs and the readout electronics within a waterproof enclosure.
• Figure 2: Details of the multiPMT module and of its positioning within the cylindrical water tank ($2$ meters in height and $4$ meters in diameter) simulated with Geant4.
• Figure 3: Energy distribution of secondary particles from 200 proton-induced EAS in the energy range between $100 - 110$$\mathrm{TeV}$ and with axis inclination between $0^{\circ} - 30^{\circ}$.
• Figure 4: Simulated Geant4 response of a WCD unit equipped with a multiPMT module. Each plot illustrates the average total PE amount per channel and first photon interaction time stamps for a $3$$\mathrm{GeV}$ single muon of different injection methods simulated 1000 times. The images show respectively the cases of vertical, down-going muons (top image) with an entry position offset with respect to the center, inclined muons traversing the tank from top to bottom with an inclination of $\theta = 50^{\circ}$ (center image), and inclined muons intersecting the WCD on the lateral sides with inclination $\theta = 80^{\circ}$ (bottom image).
• Figure 5: 2D histogram of the charge barycenters for 1000 vertical, down-going muons corresponding to the top configuration in Fig. \ref{['fig:Augerlike']}. The reconstructed barycenter is indicative of the muons off-axis initial position.