A three‐dimensional ripple trigger for the DELPHI time projection chamber

The use of a contiguity processor for fast selection of events in the DELPHI detector has already been proposed. This note presents a general description of a contiguity processor and its implementation in gate arrays. A three-dimensional ripple trigger for the Time Projection Chamber (TPC) and a fast shower builder processor for the High-density Projection Chamber (HPC) both based on contiguity ideas, are presented.