A massively parallel track-finding system for the LEVEL 2 trigger in the CLAS detector at CEBAF

Conference · Tue Feb 01 04:00:00 EST 1994 · IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States)

OSTI ID:6595278

Doughty, Jr, D C; Collins, P; Lemon, S ^[1]; Bonneau, P ^[2]

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1. Christopher Newport Univ., Newport News, VA (United States)
2. Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)

The track segment finding subsystem of the LEVEL 2 trigger in the CLAS detector has been designed and prototyped. Track segments will be found in the 35,076 wires of the drift chambers using a massively parallel array of 768 Xilinx XC-4005 FPGA's. These FPGA's are located on daughter cards attached to the front-end boards distributed around the detector. Each chip is responsible for finding tracks passing through a 4 x 6 slice of an axial superlayer, and reports two segment found bits, one for each pair of cells. The algorithm used finds segments even when one or two layers or cells along the track is missing (this number is programmable), while being highly resistant to false segments arising from noise hits. Adjacent chips share data to find tracks crossing cell and board boundaries. For maximum speed, fully combinatorial logic is used inside each chip, with the result that all segments in the detector are found within 150 ns. Segment collection boards gather track segments from each axial superlayer and pass them via a high speed link to the segment linking subsystem in an additional 400 ns for typical events. The Xilinx chips are ram-based and therefore reprogrammable, allowing for future upgrades and algorithm enhancements.

• DOE Contract Number: AC05-84ER40150
• OSTI ID: 6595278
• Report Number(s): CONF-930640--
• Conference Information: Journal Name: IEEE Transactions on Nuclear Science (Institute of Electrical and Electronics Engineers); (United States) Journal Volume: 41:1Pt1
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430303 -- Particle Accelerators-- Experimental Facilities & Equipment
440104* -- Radiation Instrumentation-- High Energy Physics Instrumentation
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ACCELERATORS
CEBAF ACCELERATOR
CHERENKOV COUNTERS
COMPUTERS
DATA ACQUISITION SYSTEMS
DESIGN
DRIFT CHAMBERS
ELECTRONIC CIRCUITS
LINEAR ACCELERATORS
MAGNETIC SPECTROMETERS
MEASURING INSTRUMENTS
MICROELECTRONIC CIRCUITS
MICROPROCESSORS
MULTIWIRE PROPORTIONAL CHAMBERS
PARTICLE TRACKS
PROGRAMMING
PROPORTIONAL COUNTERS
PULSE CIRCUITS
RADIATION DETECTORS
SCINTILLATION COUNTERS
SHOWER COUNTERS
SPECTROMETERS
TRIGGER CIRCUITS