A FADC-based Data Acquisition System for the KASCADE-Grande Experiment

Wolfgang Walkowiak

Experimental Particle Physics University of Siegen, Germany for the KASCADE-Grande collaboration

IEEE Nuclear Science Symposium October 18, 2004

IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen E-mail: [email protected] Cosmic Rays and Cosmic ray particle

interacts with molecules Extensive Air Showers in atmosphere (h=20km) Flux of Cosmic Rays 2 1 particle per m s creates extensive air shower (EAS) g ~ 2.7 Knee: 1 particle per m2 year

g ~ 3.1 ~106 secondary particles (for 1015 eV proton)

sampled and recorded in e/m/g detector array 1 particle per km2 year The physicist's interest: KASCADE- [S.P.Swardy et al., Grande The primary particle's type? Sci. Amer., 1997] The primary particle's momentum?

IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen KASCADE-Grande KASCADE array Experiment Grande-array (700 m x 700 m) of 37 former EAS-Top stations allows measurements up of EAS to 1018 eV One Grande station contains 10 m2 of plastic scintillator read out by photomultipliers

Grande station

IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen Motivation for the FADC-DAQ-System

Simulated pulse Simulated pulse Sampled pulse 66.5 m from 493.8 m from shape provides shower core shower core additional information to analysis! 4 ns sampling provides time resolution on 1 ns scale Improvement of data quality 1018 eV Fe-induced shower (full MC simulation)

IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen Concept of the FADC-DAQ-System

System features: Self triggering Dead-time free High resolution (12 bit FADC) High time resolution (250 Msamples/sec) Optical data transfer IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen FADC Digitizer Board

Comparator: programmable threshold starts FADC readout

2 PM inputs: high & low gain

2 x 4 FADCs (AD 9238): 12 bit resolution 62.5 MHz sampling freq. each 4 FADCs cascaded with 4 ns offset Fast optical -> 250 MHz effective link to DAQ sampling frequency station

IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen Receiver Board VME

Optical receiver for 1 Grande station

Input from up to 8 Grande stations

Buffering of up to 8 K FADC samples, ie 16 x 1 ms periods per input channel

LVDS interface for data transfer to PCI card

IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen PCI Interface Card From receiver board

PCI bus Features: Commercial PCI prototyping board Custom made electronics on piggyback board Direct Memory Access (DMA) for fast data transfer to PC Data transfer rate achieved: 85 MB/s Commercial PCI Piggyback (needed: 20 MB/s) prototyping board board

IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen Buffering of data up to 45 s Event Building Search for coincidences Event selection criteria adjustable by software Flexible for future extensions Stations deliver: 3737 xx 2.2.55 MBMB//ss

reduced to

100 kB/s to storage

IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen System Installation

Two Grande stations data - high gain recently equipped with FADC-DAQ system. Typical data rate: 2.5 kHz per station for single muon events (threshold dependent) Data taking with data - low gain complete FADC-system is scheduled to start is beginning of 2005. x a d e

Looking ahead to m o o 3 years of exciting data. z

IEEE Nuclear Science Symposium 2004, Rome Wolfgang Walkowiak, University of Siegen