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HK: Physik der Hadronen und Kerne

HK 14: Instrumentation und Anwendungen I

HK 14.2: Vortrag

Dienstag, 20. März 2001, 14:45–15:00, A

Digital triggering and timing for tracking arrays — •W. Gast, R.M. Lieder, L. Mihailescu, and M.J. Rossewij — Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich

Modern digital signal processing techniques have to be employed for the pulse shape analysis in γ-tracking arrays to extract the information about number, released energies, and positions of the interactions. In order to avoid additional analog hardware for basic functions like triggering and timing these functions should be performed by digital means, too. Since the sampled detector signals represent time discrete information new concepts had to be developed. The Slope Condition Counting (SCC) digital trigger algorithm aims at good low threshold performance and reasonable accuracy with low sensitivity to amplitude and shape fluctuations to allow on-line coincidence timing. The Normalized Step Response (NSR) digital timing discriminator aims at high timing accuracy with sub sampling interval resolution comparable to that of an analog Constant Fraction Discriminator (CFD). It was shown, that both algorithms could be implemented on a new Pulse Processing Analog to Digital Converter (PPADC) module to allow on-line processing in real time. The new PPADC module is optimized for the bandwidth and dynamic range of existing preamplifiers with respect to sampling speed and resolution. In this contribution we present experimental results of performance tests of the algorithms obtained with this setup. Work supported by the EU under the TMR contract ERBFMRXCT970123