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astro-ph/0206371

astro-ph/0206371. Outline. Concept * Deployment Status Event Rate Calculation Interaction rate * Simulation of signal generation * Propagation * Detector response V eff * Event Reconstruction Backgrounds & Filters * August 2000 data Data summary * Limits * Discussion

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astro-ph/0206371

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  1. astro-ph/0206371

  2. Outline • Concept * • Deployment Status • Event Rate Calculation • Interaction rate * • Simulation of signal generation * • Propagation * • Detector response • Veff * • Event Reconstruction • Backgrounds & Filters * • August 2000 data • Data summary * • Limits * • Discussion • Systematics * • LPM & hadronic showers *

  3. Radio Detection of High Energy Neutrinos * Goals PeV: AGN 1 km3 EeV: GZK 103 km3 Cherenkov radiation from n-induced in-ice shower S ~ DQ ~ 0.25 Es/GeV l ~ RM ~ 10 cm Transparency > 1 km Thermal noise @ 250 k

  4. Pole: Deployment • 16 Rx (10 cm dipole) • 5 Tx • 3 Horns • 4 Oscilliscopes (x4) • DAQ • PCs • Pulse Generator • Dry hole Kansas: • Network analyzer • Antenna range

  5. Interactions and shower simulations * • Interaction Model • ne isotropic from upper hemisphere (2p) • charged current only • Gandhi et al. ’98 cross-section ds/dy with ~20% reduction for Oxygen (EMC effect) • Shower simulation • GEANT 3.21 30% smaller than ZHS (but …GEANT 4 ??) • LPM from Alvarez & Zas • no contribution from hadronic cascade

  6. Radio Attenuation in Ice * e = e’ + i e” Red – Westphal (Greenland) + Matsuoka (high freq) Black – Kawada(lab) + Matsuoka (high freq) (from Matsuoka) RICE bandpass Solid – Provorov (used by RICE) Dashed – Matsuoka + Westphal RICE bandpass

  7. Pulse shape simulation * A lot of work has gone into calibration of antennas, amps, cables, DAQ. See astroph/0112372 Background taken from data sample Disc. threshold

  8. Results of MC simulation * 60,000 e- showers at E = 1 EeV Black dots – sample Red dots – location of events which trigger RICE ~ 5% efficiency Limited by attenuation Limited by Cherenkov angle

  9. RICE effective volume for e-,g showers * Multiply by 2p sr Range due to varying attenuation by 0.5-2 Range due to varying signal strength by 0.5-2

  10. Reconstruction & Man made noise This is actually a transmitter event ! • dt =50 ns for noise • dt = 25 ns for n • dr = 10 m nearby • dr = 0.1 R , < 1 km • dq ~ 10 deg • dE/E ~ 0.5

  11. Thermal Background * Red – Simulated detected showers (1 EeV) Black – Simulated noise – uncorrelated background Warnings: shower vertices are “true” positions not reconstructed. Should be OK inside 1 km. shower vertices are monoenergetic.

  12. Results of Data Analysis * 333.3 hrs livetime

  13. Limits on diffuse ne flux from e- showers * • Stecker & Salamon (AGN) • Protheroe (AGN) • Mannheim (AGN) • Protheroe & Stanev (TD) • Engel, Seckel & Stanev (GZK) • Ranges are central 80% AMANDA (Hundtermark)

  14. Potential Systematic Effects *

  15. LPM and hadronic showers * “Hadronic” Es = 20% En Without LPM With LPM

  16. Limits on power law fluxes PRELIMINARY Top set: ne CC only Bottom set: all n’s CC+NC AMANDA (Hundtermark) GZK challenge!

  17. Summary • Radio detection has a bright future • Demonstrated ability to reject surface backgrounds and work close to thermal limit • Major uncertainty is • attenuation in ice (high energy) • calibration (low energy) • Veff (E > 1018eV) > 20 km3 sr [ne CC only] • Limits will improve by 4-10 with inclusion of hadronic channels • Limits may improve by 10 (again) with analysis of 1 yr data.

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