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Description
The detection of cosmic radiation is a fundamental tool for studying phenomena associated with particle physics, astrophysics, and instrumental applications. This work presents the design, construction, characterization, and simulation of a modular Cherenkov detector based on a cylindrical polymethyl methacrylate (PMMA) rod for recording atmospheric muons produced by cosmic radiation. The system was developed to detect photons generated by charged particles passing through a dielectric medium at speeds greater than the speed of light in that material.
The detector consists of a PMMA rod 60.09 cm long and 10.3 cm in diameter, instrumented with photomultiplier tubes (PMTs) strategically placed according to the Cherenkov emission angle calculated for relativistic muons. Modular supports were designed using 3D printing, and an optical and electromagnetic isolation system was implemented using black felt and an aluminum coating.
As part of the experimental characterization of the detector, relevant optical and physical properties of PMMA were determined. A density of ρ=1.15±0.002 g/cm³, a refractive index of n=1.47±0.35 and an attenuation coefficient of μ=0.0052±0.0015 cm⁻¹. Based on these parameters, a Cherenkov angle of 47.76° was estimated for muons with an average energy of 4 GeV.
The response times and amplitudes of the photomultipliers were also calibrated to discriminate signals associated with particles incident from opposite directions.
Additionally, a Monte Carlo simulation was developed using Geant4, incorporating the optical properties of the system and the complete experimental geometry. The results obtained show agreement between the experimental and simulated responses, allowing the identification of temporal and spectral distributions associated with the detection of Cherenkov photons.
The developed prototype demonstrates the feasibility of using low-cost PMMA-based Cherenkov detectors for cosmic radiation detection, teaching, and scientific instrumentation applications, and also constitutes a scalable platform for future multipurpose particle detection systems.