Instrument for Ionization Measuremts in Bubble Chamber Films

A device for ionization measurements of elementary particle tracks in bubble chamber films will be described. This instrument measures the differential gap length distribution, the total blob number and the lacunarity. The process is for the most part automatic using a simple track following and gap detecting technique. Maximum speed is about 0.8 mm/sec for a track with an average bubble diameter of 40¿. Except for a power amplifier the device is completely transistorized. The light sensitive elements are silicon photo elements and a photo resistor. Results from measurements on secondary tracks of the ¿p interaction in the 81 cm hydrogen bubble chamber show good agreement with the theoretical curves.