Muon, pion and kaon lifetime measurements

We describe a simple experimental setup that can be used to measure the lifetimes of muons, pions and kaons from the secondary cosmic-ray radiation. It uses a sealed container filled with 35 1 of liquid scintillator and simple data acquisition hardware. The detector uses a 2'' photomultiplier (PMT) that collects the scintillation light produced by charged particles crossing the detector volume. The electronics used consists of 4 NIM modules, a digital oscilloscope and a PC. This equipment is multipurpose and can be conventionally found in any modern physics laboratory. The results obtained by fitting data to the muon, pion and kaon lifetimes are the following: τμ =2.208±0.027 μs, τπ=24.6±3 ns and τK= 12.5±2 ns. The measured plus-to-minus charge ratio of cosmic ray muons for a latitude of 20 deg. North is 1.28±0.06. These values are in good agreement with the literature