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Calorimetry Of The RICE Detector

Calorimetry Of The RICE Detector. Soebur Razzaque University of Kansas For the RICE Collaboration. Radio Ice Cherenkov Experiment (At the South Pole). RICERS MIT : I. Kravchenko Florida State U. : G. M. Frichter U. Delaware : D. Seckel, G. M. Spiczak

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Calorimetry Of The RICE Detector

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  1. Calorimetry Of TheRICE Detector Soebur Razzaque University of Kansas For the RICE Collaboration

  2. Radio Ice Cherenkov Experiment(At the South Pole) RICERS • MIT : I. Kravchenko • Florida State U. : G. M. Frichter • U. Delaware : D. Seckel, G. M. Spiczak • U. Canterbury : J. Adams, S. Seunarine • U. Kansas : C. Allen, A. Bean, D. Besson, D. J. Box, R. Buniy, D. McKay, L. Perry, J. Ralston, S. Razzaque, D. W. Schmitz. Thanks to AMANDA for logistic support

  3. RICE Physics • Aim ” Detect UHE neutrinos (n), with En > 1015 eV • Technique ” Coherent Radio signal from Cherenkov radiation • Astrophysics – n’s give best reach in distance and energy ” probe remote sources AGN’s, GRB’s, Monopole decays, Topological defects ” seek n • HEP – n N cross-section, flavor oscillations, non-SM physics. • Geophysics – n tomography of Earth’s mantle. • New Physics ?

  4. Radio Detection Jelly, ~1960 : Radio signal from air showers Optical vs. Radio (P.B. Price) • Askaryan, 1962 : • Net charge imbalance • Coherent radio power emission RF transparent Antarctic ice : Latten ~ 1 - 10 km for n ~ 1 - 0.1 GHz Saltzberg et. al., 2000 : Experimental proof of radio signal from electromagnetic cascade in dense media

  5. RICE Concept RICE Concept Air Firn Layer Cascade shower ~100 m UHE ne Radio transparent Ice qc ~ 56 0 300 m e ne w n/p x n N CC-interaction ~ 80% of En to e C-pulse

  6. MAPO Martin A. Pomerantz Observatory House of AMANDA, SPASE and RICE electronics Photo by AMANDA personnel

  7. Antenna Deployment • 200 m x 200 m x 200 m Array • 100 m – 300 m depths As of 2002 20 Receivers (Rx) 5 Transmitters (Tx) 3 TEM Surface horns 200 MHz High-pass Filter 52/60 dB amp. ~ 300 m cable Scope 36 dB in-ice amp. CAMAC Dipole Antenna 0.2 – 1 GHz 30 cm 14 Rx in AMANDA-B holes 6 Rx in dedicated RICE holes

  8. Event Triggers and Veto Rates Preset time window: Dt = 1.2 ms ; Preset discriminator threshold: Vth ~ 400 mV Triggers Raw trigger rate ~ 30 Hz • 4 Rx hits within Dt above Vth • 1 Rx hit and 30 fold AMANDA • 1 Rx hit and big SPASE pulse OR DAQ AND Vetoes NOT Veto time ~ 10 ms/event • 1 surface horn hit • Surface noise match in software OR Forced/unbiased trigger every 600 s

  9. Data Acquisition Write data to disk ~ 10 s/event Typical live time ~ 80%

  10. Waveform HP54542A scopes 500 MHz bandwidth 1 GSa/s 8912 ns traces Shallowest TDC time in Rx Channel Rise time resolution ~ 2 ns Typical ring time ~ 20 ns Deepest Time (ms)

  11. Timing Calibration Time of hit (TDC time) ” First excursion exceeds 6srms srms - from unbiased triggers (updated every 600 s) dtij (measured) – dtij (expected) after calibration • Short duration pulse from Tx • Channel-to-channel (ij) timing delays dtij (measured) from at least 4-hits. • Calculate dtij (expected) from re-constructed source locations. • Minimize - c2 (dtij) • Timing calibration ~10 ns/Rx Events Timing resolution ~ 1.5 - 2 ns after calibration Time difference (ns)

  12. Vertex Re-construction Re-constructed 97Tx3 Pulse Source • Analytic Method • Solve | rRx - rsource | = (c/n) t • for each of 4-hit Rx • Grid-based Method 2 km x 2 km x 2 km grid • with 10 m spacing • Minimum - c2 gives vertex • Source Direction Superimpose a Cherenkov cone of 560 half-width Vertex error ~ 5 m

  13. Gain Calibration • In situ measurements • Full circuit (amps + cable + splitters etc.) • 1 mW CW signal from Tx • 0-1 GHz in 1000 bins • Study Rx response HP8713C NWA Circuit Gain for 97Tx3 to Ch. 11 (98Rx5) Compare to expected gain from KUATR data with following • heff (w) of the Rx • Tx/Rx efficiency (q, j) • Cable losses • Simulated thermal noise • No absorption in ice Return-power/Transmit-power (dB) Expected Full circuit gain uncertainty +/- 6 dB Frequency (MHz)

  14. (Expected – Measured) Full Circuit Gain 3 Tx broadcasting To 16 Rx 200 – 700 MHz range 1 MHz bins Summed over freq. Events Measured uncertainty is better than expected +/- 6 dB

  15. MC Event Generation Specify vertex location Specify neutrino energy Event GEANT simulation of Radio signal in ice 1 km Thermal noise simulated at each antenna amp. gain + cable loss calculation < 2 km < 2 km Receiver time (+/- 2 ns) Voltage (+/- 6 dB in gain) Reconstruction

  16. Re-constructed and Simulated Depth of a Tx Analytic 4-hit vertexing

  17. MC Simulation of Vertex Depth Resolution 10,000 Events with En = 10 PeV 4-hit vertexing algorithm True interaction depth Z meters Few events Many events DZ (Reconstructed – True) meters

  18. MC Simulation of Angular Resolution Events with En = 10 PeV > half events with Dq < 100 Events Dq (True – Reconstructed) degrees

  19. MC Simulation of Energy Resolution < 10-hits > 10-hits Events log10(reconstructed E / true E)

  20. Flux Limit RICE Array Effective Volume • Veff (En) from MC • Flux model + snN” dN/dVdt (showers/vol./yr.) • Veff (En) x dN/dVdt ” dN/dEdt (no. events/E-bin/yr.) • Integrate dE x dN/dEdt ” dN/dt (no. of events/yr.) • How large can flux be And still see zero events from Poisson statistics @ 95% CL ? ” Upper limit on flux Effective Volume (km3) Cascade Energy (PeV)

  21. RICE Limits on Electron Neutrino Flux 102 Preliminary 100 Flux limits at 95% CL 10-2 10-4 dN/d(ln E) (cm-2 sr-1 yr-1) 10-6 10-8 10-10 10-12 10-2 100 102 104 Neutrino Energy (PeV)

  22. Conclusion • Basic calibrations (Timing, Amplitude) are done primarily using data in situ • Monte Carlo simulation of the detector is written ” reproduces gross features of calibration data • Upper limit on neutrino flux is produced based on • effective volume of the experiment • 4 different flux models • 1 month of data • RICE demonstrates: Radio detection can be used for • Vertex re-construction • Angular resolution • Energy resolution • Real, working detection method with considerable potential • Cost-effective

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