Cosmic Ray Spark Chamber

In the 1960’s and ’70s, spark chambers were commonly used as detectors in particle physics experiments. They served as visual detectors with moderate spatial resolution (≈ ±0.5 mm) and time resolution (≈ ±0.5 μs). Higher spatial and temporal resolution detectors, such as drift chambers and silicon detectors, have since replaced these. However, the spark chamber is still well suited for lecture demonstration — the detection of cosmic rays (usually muons) can easily be made visible to a large audience. About 80% of the cosmic ray flux at sea level is composed of muons, with electrons and protons making up the remainder. For more details on our setup see