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HK: Fachverband Physik der Hadronen und Kerne

HK 10: Instrumentierung II

HK 10.7: Vortrag

Montag, 15. März 2010, 18:00–18:15, HG ÜR 6

Design and beam-test of an FPGA based tracking trigger for a scintillating fibre array — •Anselm Esser — Institut für Kernphysik, Universität Mainz

The electron-arm detector of the Kaos spectrometer at the Mainz Microtron MAMI consists of two planes of 18 432 scintillating fibres with 4608 read-out and trigger channels. Due to the geometrical arrangement of the fibres, each particle hit causes a set of correlated signals in neighbouring channels. The implemented algorithm detects these signal clusters and rejects noisy signals or hits from particles which cross the detector under small angles. The particle trajectories are reconstructed by identifying temporal coincidences between the detector planes. An angular acceptance test is performed on-line for the reconstructed track, to assure its origin from the target.

The hardware set-up comprises about 40 VUPROM modules with 256 I/O channels each. Each 6U VME module, developed by the Electronics Department of GSI, is equipped with a Virtex-4 FPGA chip, capable of operating at 400 MHz. This setup allows easy reprogramming via VMEbus. Furthermore, output and control information is accessible during trigger operation.

Trigger design, implementation and performance results from measurements with the fibre detectors positioned under very forward angles to the electron beam will be discussed.