Data acquisition for the LLNL fractional-charge search

A data acquisition system has been implemented on an experiment to detect the presence of fractional charges in bulk matter. The experiment utilizes a liquid-droplet generation technique coupled to a large electrostatic charge spectrometer. Charges are determined by measuring the deflection of each droplet after falling 5 m in the spectrometer field. Data acquisition is accomplished via a flying-spot light source and a photomultiplier tube connected to fast nuclear instrumentation (NIM) and computer automated instrumentation (CAMAC) electronics. An LSI 11/73 mini-computer is used for data taking as well as data analysis. Data can be accumulated at rates up to 20,000 droplets per second. 6 refs., 9 figs.