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Radiowave shower detection (GV, also) – cf optical/acoustic

Radiowave shower detection (GV, also) – cf optical/acoustic. Basic parameters: Transparency ~ 2 km vs. 40 m ice/water Radio ‘coherence’  quadratic growth of signal power at >20 cm wavelengths (vs. linear for optical/PMT)

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Radiowave shower detection (GV, also) – cf optical/acoustic

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  1. Radiowave shower detection (GV, also) – cf optical/acoustic Basic parameters: Transparency ~ 2 km vs. 40 m ice/water Radio ‘coherence’  quadratic growth of signal power at >20 cm wavelengths (vs. linear for optical/PMT) Now extensive experience in situ (RICE) + 3 beam tests at SLAC by GLUE/ANITA groups RMoliere

  2. Why believe radio? • Attenuation length in situ data • Test beam data consistentcoherenceGHz

  3. In situ absolute system gain calibration (~dE/E) using calibrated radio sources • RICE (gain error~3 dB) • ANITA (~ 0.5 dB) • In situ reconstructed radio sources (Tx) • Observation of l=10 m radio coherence in coincidence w/ EAS (LOPES/KASCADE) • Signal strength~Allen formula (from 60’s)

  4. Lower bar for radio (optical/EAS) AUGER, EUSO -geometry of inclined shower detection VERY distinctive Contained events better-reconstructed than events outside detector

  5. Efforts + Ideas • RICE, ANITA (In progress) • LOPES, CODALEMA, South-Pole-effort-with-which-I’m-not-very-familiar (Jeff Peterson,CMU) • Air shower detection • AURA, SALSA, ARIANNA • In planning/seed-funding • ROAST + other stationary elevated options • Europa (3-10 km thick ice [+salts and/or sulfuric acid] @ 91 K) • Surface Wave coupling of radio waves (evanescent solutions of Maxwell’s eqns.)

  6. In-Progress Efforts

  7. RICE ANITA beam test (SLAC, June 2006)

  8. ARIANNA – ice characterization 06-07 (steve barwick talk)

  9. Air shower detection of EAS (Heino Falcke, plenary) Threshold~100 PeV, LOPES must be externally triggered by ground detectors. 5 highly inclined events in 2004 data.

  10. SALSA

  11. Salt • Experimental site on continental US? • Surface layer+water  ‘insulating barrier’, but: • Uncertain salt properties, site-to-site • Lab measurements encouraging but not fully fleshed out (Latten~50 m  1 km) • High Drilling Costs • (~1M/hole vs. 50K/12 cm, 1 km deep hole at Pole)

  12. Upper limits (Saltzberg)

  13. Upper limits (Hussain) Cautions: 1) presented upper limits can `float’ horizontally (no energy resolution), 2) different model parameters used for different modes, 3) 90% vs. 95% C.L. limits, 4) results depend on binning

  14. Do we need multiple radio expts? • Threshold~experimental scale (coincidence trigger requirement) • 1013 eV threshold (104 elements, 20 m spacing, surface array [Greenland]) viewing upcoming Sgr*A neutrinos • 100 m spacingDense packed expt (RICE, e.g.); showers typically several km distant1017 eV • 38 km height; showers typically 100 km distant1019 eV threshold (ANITA)

  15. Atm. Nu:IceCube = X:radio; X NOT air showers RICE ANITA

  16. PMT noise:IC=Thermal noise:radio • Band-limited response from noise ~ band-limited response from signal • Probability for a false trigger in one N-sample waveform~Nexp(-x2/2s2), assuming Gaussian noise spectrum, with x=trigger threshold criterion (2.5-sigma, e.g.). • GLUE/ANITAGaussian • RICEnon-Gaussian tails: x=5, N=8192P=0.03/channel • For a big array, thermal noise is statistically characterizable: vertices cluster within array, with vertex distribution determined by coincidence window • Caution: most expts. Operating very close to the ‘edge’!

  17. RICE trigger rate(threshold)

  18. Trigger multiplicity vs. Reconstruction multiplicity • Trigger: Minimum of 4-hits needed to solve ct0=(x,y,z) • (quadratic ambiguity) • (RICE) biggest problem = N ‘real’ hits + M `noise’ hits • minimum hit multiplicity from 45 to `isolate’ noise hit via residuals, e.g.

  19. Acoustic compared to Radio +)10 km Latten? +) 20 khz-50 khz digitization and signal transmissioncan do all triggering/DAQ on surface with no high-frequency signal losses +) Ray tracing insulates acoustic waves produced at surface from interior +) No battle with RF backgrounds 0) both polarizations -) 1/f noise forces threshold up to 1019 eV BEST IF YOU CAN DO BOTH!

  20. Secular* Grail: Simultaneous obs.!GZK evts / hybrid dector (c. 2010) N.B: coincidences offer lower thresholds (50%?), enhanced event reconstruction (Justin Vandenbrouke WG talk tomorrow) *(an obscure reference to local KS politics; not crucial to understanding talk as a whole)

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