[en] The UA1 First Level Trigger Processor (TP) is a fast digital machine with a highly parallel pipelined architecture of fast TTL combinational and programmable logic controlled by programmable microsequencers. The TP uses 100,000 IC's housed in 18 crates each containing 21 fastbus sized modules. It is hardwired with a very high level of interconnection. The energy deposited in the upgraded calorimeter is digitised into 1700 bytes of input data every beam crossing. The Processor selects in 1.5 microseconds events for further processing. The new electron trigger has improved hadron jet rejection, achieved by requiring low energy deposition around the electro-magnetic cluster. A missing transverse energy trigger and a total energy trigger have also been implemented

[en] The new first-level trigger processor for UA1 is now near completion. An extremely versatile range of triggers will be provided by this fast hard-wired system. 2 refs, 2 figs

[en] Short communication

[en] The increased luminosity of the improved CERN Collider and the more subtle signals of second-generation collider physics demand increasingly sophisticated triggering. We have built a new first-level trigger processor designed to use the excellent granularity of the UA1 upgrade calorimeter. This device is entirely digital and handles events in 1.5 μs, thus introducing no deadtime. Its most novel feature is fast two-dimensional electromagnetic cluster-finding with the possibility of demanding an isolated shower of limited penetration. The processor allows multiple combinations of triggers on electromagnetic showers, hadronic jets and energy sums, including a total-energy veto of multiple interactions and a full vector sum of missing transverse energy. This hard-wired processor is about five times more powerful than its predecessor, and makes extensive use of pipelining techniques. It was used extensively in the 1988 and 1989 runs of the CERN Collider. (author)

[en] The Cluster Finding Module (CFM) is part of the UA1 Trigger Processor constructed at the Rutherford Appleton Laboratory for use at CERN. The CFM detects and counts two dimensional clusters of electromagnetic particles. This process requires 75nS for detection of either isolated or non-isolated clusters and 75nS to count them. This is equivalent to a peak computational rate of 11,000 mips per module (3,000 mips average). The required high logic density and speed are achieved by using programmable array logic devices (PALs) within a pipelined system. The design has been strongly influenced by the need for in-situ computer testing

[en] The Central Tracking Detector (CTD) of the ZEUS experiment uses a Flash Analogue to Digital Converter (FADC) readout system to measure the arrival time of ionization at sense wires as well as the charge deposited. A digitization frequency of 104 MHz is used and the data is written to pipelined data stores. A Digital Signal Processor (DSP) is used to control the main functions on the card as well as perform data parameterization and compression. Test and operational performance results from the first electron-proton interactions are presented

[en] The very high spatial resolution required by the ZEUS Tracking Detectors and the 96ns periodic interaction between protons and electrons of the Hera collider require real time Analogue Signal Digitization at 104MHz controlled reliably to tight tolerances. Maximum event readout efficiency, fast monitoring of run time errors and testability of front end electronics require pipelining, speed and flexibility. Such an electronic Timing and Control System (TCS) is operational within three main inner detectors of the ZEUS detector and is presented in this paper

[en] A new first-level trigger processor has been built for the UA1 experiment on the Cern SppS Collider. The processor exploits the fine granularity of the new UA1 uranium-TMP calorimeter to improve the selectivity of the trigger. The new electron trigger has improved hadron jet rejection, achieved by requiring low energy deposition around the electromagnetic cluster. A missing transverse energy trigger and a total energy trigger have also been implemented. (orig.)

[en] The increased luminosity of the improved CERN Collider and the more subtle signals of second-generation collider physics demand increasingly sophisticated triggering. We have built a new first-level trigger processor designed to use the excellent granularity of the UA1 upgrade calorimeter. This device is entirely digital and handles events in 1.5 μs, thus introducing no dead time. Its most novel feature is fast two-dimensional electromagnetic cluster-finding with the possibility of demanding an isolated shower of limited penetration. The processor allows multiple combinations of triggers on electromagnetic showers, hadronic jets and energy sums, including a total-energy veto of multiple interactions and a full vector sum of missing transverse energy. This hard-wired processor is about five times more powerful than its predecessor, and makes extensive use of pipelining techniques. It was used extensively in the 1988 and 1989 runs of the CERN Collider. (orig.)

[en] The readout system developed for the ZEUS central tracking detector (CTD) is described. The CTD is required to provide an accurate measurement of the sagitta and energy loss of charged particles as well as provide fast trigger information. This must be carried out in the HERA environment in which beams cross every 96 ns. The first two aims are achieved by digitizing chamber pulses using a pipelined 104 MHz FADC system. The trigger uses a fast determination of the difference in the arrival times of a pulse at each end of the CTD. It processes this data and gives information to the ZEUS global first level trigger. The modules are housed in custom-built racks and crates and read out using a DAQ system based on Transputer readout controllers. These also monitor data quality and produce data for the ZEUS second level Trigger. (orig.)