'Megahpol' - a fast on-line noncomputer multiparameter data reduction system

This note describes why we eliminated on-line computers from our experiments and how we replaced them with a faster “MEGAHPOL” (MEGA-event Hardware-Programmed On-Line) data reduction system. MEGAHPOL is capable of reducing data in multiparameter experiments involving readout of up to 100 scintillation counters at a rate of 100 000 events per second. Integrated circuit interface elements are wired according to a program determined by the physics objectives. The interface reduces the contents of the counters into one word which is stored in a special purpose multi-channel analyzer. At the end of each 30 min run the analyzer memory, containing typically 10 7 events binned in up to 4096 combinations, is dumped onto magnetic tape.