Gas Electron Multiplier-Based Cosmic Muon Tracking System for Characterizing Cherenkov Detectors

Cherenkov detectors are widely used in experimental nuclear and particle physics for particle identification and counting. Typically, Cherenkov light produced by relativistic charged particles traversing a radiator is detected using photomultiplier tubes (PMTs), with the light yield dependent on the properties of the incident particles.

The MOLLER (Measurement Of a Lepton Lepton Electroweak Reaction) experiment at Thomas Jefferson National Accelerator Facility in Virginia aims to perform a high-precision measurement of the weak mixing angle, an essential parameter of the electroweak theory via Møller scattering. A Cherenkov detector with fused silica radiators and air light guides has been proposed as one of the main detector sub-systems for the experiment. To evaluate the performance of the prototype Cherenkov detector modules using cosmic muons, a triple Gas Electron Multiplier (GEM) based tracking system has been developed at UMass, Amherst. This system consists of three triple-GEM chambers to reconstruct cosmic muon trajectories. The setup has been utilized to study the photoelectron (PE) yield response of the Cherenkov modules, including its angular dependence. A detailed characterization of GEM chambers has also been carried out using Fe-55 source and cosmics.

In this poster, the experimental setup, the track reconstruction methodology, and the results obtained from the GEM characterization and prototype Cherenkov detector modules, including the angular dependence will be discussed.