The CLEO III RICH detector

The Ring Imaging Cherenkov (RICH) detector is the newest addition to the array of detectors in CLEO III. The detector was added to make it easier for experimenters to tell the difference between pions and kaons, two particle which leave very similar tracks in the other detectors. The detector design takes advantage of the Cherenkov effect. Charged particles traveling at almost the speed of light create a UV photon shock-wave as they pass into the more dense material of the radiator. These Cherenkov photons strike the photon detector plates in a ring centered on the particle's path. The ring size increases with the particle velocity. By measuring the radius of the ring, the physicists can calculate how fast the particle was moving. This data plus the measurements made in other detectors, helps them to identify the particle.
Click to learn more about the RICH detector

The RICH detector is sandwiched between the drift chamber and the calorimeter layer. (for more details, click on the picture)
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The particle path is the purple line,the Cherenkov photon path is the orange zig-zag line.

This page was developed by five high school science teachers from the Detroit, Michigan metropolitan area and funded by the National Science Foundation RET Program. The teachers are: Ron Arscheene (Utica Community Schools), Gary Lalli (St. Florian), Robert Santavicca (Detroit Public Schools), Wilbert Sherrod (Detroit Public Schools), and Eric Wisniewski (Dearborn Public Schools).