Some Solutions to Data-Handling Problems Associated with the Magnetostrictive Spark Chamber

Abstract

The invention of the magnetostrictive spark chamber has created problems in detecting, digitizing, and storing the data from arrays of such chambers. These arrays are expected to vary widely in size from one experiment to another. The system of electronics developed for such use should be easily adapted to arrays of different size, and economically feasible for use with the largest arrays. Such a system is described. The basic components of the system are a preamplifier, timing discriminators, and digitizing and storage electronics. The preamplifier, designed to be mounted at the spark chamber, uses an integrated-circuit operational amplifier. It amplifies and clips the pulses from the transducer. The zero-crossing timing discriminator uses a tunnel diode in a cock-trigger circuit. The timing characteristics of the discriminator with expected variations in input pulse shape are described. The digitizing of spark location is accomplished with start/stop scalers operating with a 20-MHz clock. Scalers of 12-bit capacity can be used with chambers as large as 1 meter on a side. The digitizing and storage electronics has been designed in modular form. The number of channels (transducers) and the number of sparks per gap can be expanded or contracted as required by a given experiment. The system can be used with any of three modes of connecting the transducers: parallel, series, or parallel-series. The use of integrated circuits has led to simplifications in the design and economies in production.