Data-acquisition system for a time-projection chamber

A data acquisition system has been designed to digitize the trajectory information of muon decay every eight milliseconds. A time projection chamber is used which operates in a solenoidal magnetic field. It has 315 sense wires which induce signals on 5355 pads and thus create approximately 402,000 bits of data for each event or 55 megabits per second. Most of the data are zeros which are handled using a hardware-aided compaction scheme. The meaningful data are extracted by a modular system consisting of three basic building blocks: flash encoders with associated storage, wire hit memory boards, and bit-slice data preprocessors, which are described.