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This paper describes the deduction of pulse arrival times from digital waveforms recorded with a multichannel data-acquisition (DAQ) system. A linear rise approximation (LRA) arrival timing method provides restricted timing resolution for pulses with nonlinear rise. It reaches 1/20th of the sampling period, if the relation between signal shaping and sampling rate is optimized. We introduce a nonlinear rise approximation (nLRA), which reduces the sampling phase error (SPE) down to less than 1/100th of the sampling period. The proposed timing algorithm uses a single free parameter that can easily be adjusted for various radiation detectors. The technique permits using a rather slow pulse shaping and low sampling rates, thus strongly reducing power consumption and the costs of the system. A high-density DAQ system integrating over 2000 channels inside an OpenVPX crate is presented. A prototype has been tested in the proton beam at cooler synchrotron (COSY) at Jülich Research Center (Germany). [ABSTRACT FROM AUTHOR]

The PANDA (AntiProton Annihilations at Darmstadt) experiment is being built at the new Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany. PANDA will measure antiproton-proton annihilation reactions in the charm quark mass range to investigate the nature of the strong interaction. This particle physics experiment will run at very high reaction rates of 10–20 MHz. Our work is related to an ADC (analog-to-digital converter) based data acquisition system for the PANDA Straw Tube Tracker (STT). The STT will be able to deliver data rates up to 20 GByte/s through over 4600 signal channels and could require major efforts for the hardware implementation as well as high offline processing power. Test beam studies were carried out in order to specify a proper system architecture with feasible hardware and to reduce output data stream to a level suitable for offline processing. We analyze the straw tube response to both the proton beam and ^55Fe irradiation. Furthermore, we present real-time processing using the neighboring straw information and introduce the technique to reconstruct the tracks. [ABSTRACT FROM PUBLISHER]