A General Purpose Nuclear Data Acquisition System Based on an Auxiliary Crate Controller

This paper describes a readout system for nuclear and atomic physics experiments at the Heavy Ion Accelerator UNILAC. Input modules reside in CAMAC crates and are set up conventionally via the CAMAC Branch Highway. For data taking, control is transferred to auxiliary crate controllers which transfer data directly through DMA to the DEC POP-11 or VAX host computer. The readout sequence is determined for each event by bit patterns or preprogrammed lists actuated by external triggers. Four modes of operation and provision for cascading several CAMAC crates ensure expansibility and the flexibility required for a diverse range of experiments. Overall data rates in excess of 2 × 105 words per second have been achieved for single parameter events.