A digitized spark chamber for automatic data retrieval

A spark chamber is described in which the usual plate electrodes are replaced by wire grids. Toroidal ferrite memory cores threaded on these wires are set by the spark current and yield information about spark location when they are interrogated by circuits like those used in computer memories. This system may be read out very rapidly (on the order of 110 μs) if desired, permitting operation of the associated spark chamber at a rate determined by the recovery properties of the chamber itself, provided means are available to handle the large amount of information produced. Resolution of about 0.4 of a wire spacing was obtained and it is expected that the use of close wire spacings will make the main uncertainty in track location be the accuracy with which sparks indicate the true track position. Comparisons are made with other systems proposed for automatic retrieval spark chambers and test results from runs in a cyclotron beam are given. The chamber and associated circuits were designed for on-line operation with the Maniac III computer. Development work is being continued.