A muon spectrometer is an instrument used in particle physics research to detect and measure the properties of muons, which are a type of subatomic particle similar to electrons but heavier. Muon spectrometers typically consist of detector systems designed to track the trajectories of muons as they pass through a material, allowing researchers to study the muon's momentum, energy, and interactions with other particles. They are used in a variety of experiments to study fundamental particles and their properties, as well as in applications such as medical imaging and industry.