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Cosmic rays with Lofar

Cosmic rays with Lofar. Sven Lafebre et al. Radboud University, Nijmegen (NL). Overview. Part I: The Lofar telescope Part II: Cosmic ray observation modes. Lopes: a test case. Lofar. Lopes-like hardware Baselines up to 300 km. Lofar layout. Remote stations. Compact core.

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Cosmic rays with Lofar

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  1. Cosmic rays with Lofar Sven Lafebre et al. Radboud University, Nijmegen (NL)

  2. Overview Part I:The Lofar telescope Part II:Cosmic ray observation modes 6th Rencontres du Vietnam

  3. Lopes: a test case

  4. Lofar • Lopes-like hardware • Baselines up to300 km

  5. Lofar layout Remote stations Compact core

  6. Sensors in Lofar • 13 000 low band ant.(30 – 80 MHz) • 13 000 high band ant.(110 – 230 MHz) • 200 MHz sampling More sensors: • Geophones • Agricultural applications

  7. Timeline 52 M€ grant from Dutch government First test station Deploying starts Test using final hardware Operational 2003 2004 2005 2006 2007 2008

  8. Lofar science • The age of reionization(6 < z < 12) • Extragalactic surveys(radio galaxies) • Transient objects(exoplanets, pulsars) • Cosmic rays

  9. CR spectrum coverage

  10. Radio detection of air showers • Air showers produce charged particles • Trajectories are curved by magnetic field • Synchrotron radiation is emitted • Coherent up to ~100 MHz

  11. HECR mode In-beam trigger • Station looks at part of the sky • Beamed station data is triggered for pulses • Higher level triggers at central computing facility Estimated energy range:1015–1017 eV

  12. VHECR mode All sky trigger • Single dipoles are monitored • Simple coincidence trigger • Crude direction is fitted • Higher level triggers at central computing facility Estimated energy range:1017–1019 eV

  13. Radio detection off the Moon • Shower inside the Moon • Askaryan effect produces radiation • Radiation can cross Moon surface at ~100 MHz NuMoon project:J. Bacelar, A. van den Berg,R. Braun, G. de Bruyn,H. Falcke, O. Scholten,B. Stappers, R. Strom Gorham et al, 2000

  14. UHEP mode Moon observations • Beamed station data is triggered for pulses • Higher level triggers at central computing facility Estimated energy range:1021–1022 eV Scholten et al, 2006, in press

  15. Conclusion Lofar • A new generation radio telescope with many astrophysical applications • Full telescope operational: fall 2008 • More stations can be added later… Cosmic rays • Geosynchrotron effect allows direct measurements of air showers up to 1019 eV • Looking at the Moon may provide us with super GZK data up to 1022 eV within months

  16. The Lofar collaboration www.lofar.org The Lopes collaboration www.lopes-project.org The NuMoon collaboration (no website yet) NuMoon

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