Recognition and measurement of bubble chamber tracks using a flying spot digitizer

The bubble chamber is a device whereby charged particles resulting from nuclear interactions can be observed visually as three- dimensional curved tracks. From ten thousand to several hundred thousand stereo-triads of photographs may have to be analysed in a single experiment. The Flying Spot Digitizer (FSD) is one particular device for converting a bubble chamber image into digital form for input to a computer. The paper describes the basic techniques which have been developed at Cern for the recognition and precise measurement of interesting tracks from the set of about 100,000 coordinate pairs from the FSD representing each stereo-image. Some aspects of the three-dimensional reconstruction of tracks from such measurements are also considered. (7 refs).