Advances in a minimum guidance system for measuring bubble chamber film

Abstract

Hardware and software improvements have been achieved in a CRT film measuring system (PEPR). The use of histogramming techniques with a spot slice scan has greatly improved measuring accuracy, and close tracks can be resolved down to 25–30 μm on film. The track follower adaptively uses spot or line element scans according to learned track characteristics and local noise criteria. Very tight checks are applied to fitted track curves and their association with the vertex. Comprehensive operator interaction techniques have been developed for aiding difficult events. For an 11.2 GeV/ c π −p CERN 2 m exposure the single pass efficiency for complete events through track match and geometrical reconstruction has improved from 70% to 90%. The track point and ionisation measurements are also greatly improved. Track reconstruction residuals peak at 2.5–3 μm on film.