Preliminary Plans for an Automatic Scanning Facility for Bubble and Spark Chamber Photographs

This report discusses the feasibility and possible performance of an instrument for scanning bubble chamber photographs. A light line from a rotating slit scans the photographs and produces a signal for track segments in near alignment with the line. The picture is reconstructed from these line segments. Fast analog rather than digital methods are used to analyze the output signal. The subsequent reduction of the data before storage on tape can be handled by a small inexpensive computer on-line. Although the instrument can in principle achieve high precision, this will not be needed for the main initial aim, pattern recognition. In a subsequent "industrial" stage after at least 4 years of development and experience, a more complex instrument, capable of high precision and of measuring in parallel all three stereoscopic films would require a CDC 6600 on-line and could achieve an output of up to 107 triads per year. Copies of the output tape would be used directly by university laboratories for analysing the experiment, or guide more precise film measurements of selected events with a flying spot machine. The design of the instrument allows the scanning parameters to be adapted to the types of photos being scanned and to the event types.