IceCube Neutrino Telescope and the GZK n detection

1. TAUP2003 IceCube Neutrino Telescope and the GZK n detection Shigeru Yoshida, Chiba University

2. The IceCube Collaboration Institutions: 11 US, 9 European institutions and1 Japanese institution; ≈150 people • Bartol Research Institute, University of Delaware, USA • BUGH Wuppertal, Germany • Dept. of Physics, Chiba University, JAPAN • Universite Libre de Bruxelles, Brussels, Belgium • CTSPS, Clark-Atlanta University, Atlanta USA • DESY-Zeuthen, Zeuthen, Germany • Institute for Advanced Study, Princeton, USA • Dept. of Technology, Kalmar University, Kalmar, Sweden • Lawrence Berkeley National Laboratory, Berkeley, USA • Department of Physics, Southern University and A\&M College, Baton Rouge, LA, USA • Dept. of Physics, UC Berkeley, USA • Institute of Physics, University of Mainz, Mainz, Germany • Department of Physics, University of Maryland, USA • University of Mons-Hainaut, Mons, Belgium • Dept. of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA • Dept. of Astronomy, Dept. of Physics, SSEC, University of Wisconsin, Madison, USA • Physics Department, University of Wisconsin, River Falls, USA • Division of High Energy Physics, Uppsala University, Uppsala, Sweden • Fysikum, Stockholm University, Stockholm, Sweden • University of Alabama, USA • Vrije Universiteit Brussel, Brussel, Belgium

3. South Pole Dark sector Skiway AMANDA Dome IceCube

4. IceTop AMANDA South Pole Skiway 1400 m 2400 m IceCube • 80 Strings • 4800 PMT • Instrumented volume: 1 km3 (1 Gt) • IceCube is designed to detect neutrinos of all flavors at energies from 107 eV (SN) to 1020 eV

5. Design parameters: Time resolution:≤ 5 nsec (system level) Dynamic range: 200 photoelectrons/15 nsec (Integrated dynamic range: > 2000 photoelectrons) (1.p.e. /10ns ~ 160mA 10^7G ~8mV 50 W) 4V saturation500p.e. Digitization depth: 4 µsec. Noise rate in situ: ≤500 Hz Tube trig.rate by muons 20Hz DAQ design: Digital Optical Module- PMT pulses are digitized in the Ice DOM 33 cm

6. ATWD 300MHz 14 bits. 3 different gains (x15 x3 x0.5) Capture inter. 426nsec 10 bits FADC for long duration pulse. Capture Waveform information (MC) E=10 PeV String 5 String 4 String 3 String 1 String 2 Events / 10 nsec 0 - 4 µsec

7. Selection criteria (@ -40 °C) Noise < 300 Hz (SN, bandwidth) Gain > 5E7 at 2kV (nom. 1E7 + margin) P/V > 2.0 (Charge res.; in-situ gain calibration) Notes: Only Hamamatsu PMT meets excellent low noise rates! Tested three flavors of R7081. Photomultiplier:HamamatsuR7081-02 (10”, 10-stage, 1E+08 gain)

8. N

9. Digital Optical Module (DOM) Main Board Test Card

10. SPE Discriminator Scan – PMT Pulses Input (71DB)

11. The big reel for the hotwater drill

12. Energy Spectrum Diffuse Search Blue: after downgoing muon rejection Red: after cut on Nhit to get ultimate sensitivity

13. Effective area of IceCube Aeff / km2 cos  Effective area vs. zenith angle after rejection of background from downgoing atmospheric muons • Effective area vs. muon energy • - after trigger • - after rejection of atm  • after cuts to get the ultimate • sensitivity for point sources • (optimized for 2 benchmark spectra)

14. TAUP 2003 In three years operation… • E2dNn/dE ~10-8 GeV/cm2 s sr (diffuse) • E2dNn/dE ~7x10-9 GeV/cm2 s (Point source) • 200 bursts in coincidence (GRBs – WB flux) For 5s detection

15. Construction: 11/2004-01/2009 Grid North 100 m AMANDA South Pole SPASE-2 Dome Skiway Next season: Buildup of the Drill and IceTop prototypes

16. TAUP 2003 Project status • Approved by U.S. the National Science Board • Startup funding is allocated. 100 DOMs are produced and being tested this year. • Assembling of the drill/IceTop prototypes is carried out at the pole this season. • Full Construction start in 04/05; takes 6 years to complete. • Then 16 strings per season, increased rate may be possible.

17. TAUP 2003 GZK EHEn detection • What is the GZK mechanism? • EHE n/m/t Propagation in the Earth • Expected intensities at the IceCube depth • Atmospheric m – background • Event rate

18. UHE (EeV or even higher) Neutrino Events Arriving Extremely Horizontally • Needs Detailed Estimation • Limited Solid Angle Window (srNA)-1 ~ 600 (s/10-32cm2) -1(r/2.6g cm-3) -1 [km] Involving the interactions generating electromagnetic/hadron cascades mN mX e+e- TAUP 2003

19. Products ne nm nt m t p e/g ne Weak Weak nm Weak Weak nt Weak Weak Incoming e/g Cascades Decay Weak Pair/decay Bremss Decay m Pair Pair PhotoNucl. DecayPair Decay Pair Bremss Decay Decay Weak t Pair PhotoNucl. p Cascades

20. TAUP 2003

21. ± π + e － e １．４ｋｍ １ｋｍ Ice γ ν lepton １ｋｍ Rock ν Upward ν

22. Muon(Neutrinos) from nm nt Nadir Angle TAUP 2003

23. Suppression By t decay Tau(Neutrinos) from nm nt TAUP 2003

24. GZK Neutrino Production 0.6 x 10-27 cm2 2.725 K 411 photons / cm3 π ν ＋ ＋ γ μ ＋ ν e p γ p n E = 10 20 eV Conventional Mechanism of EHE neutrinos!! E 0.8 x 10 20 eV ~

25. Yoshida and Teshima 1993 Yoshida, Dai, Jui, Sommers 1997 TAUP 2003

26. Upward-going TAUP 2003

27. Downward going!! TAUP 2003

28. ν Downward lepton γ γ ± π + + e e － － e e １．４ｋｍ １ｋｍ Ice γ ν lepton １ｋｍ Rock ν Upward

29. 11000m 2800 m 1400 m Down-going events dominates… Up Down TAUP 2003

30. Intensity of EHE m and t [cm-2 sec-1] TAUP 2003

31. Atmospheric Muons! • Major Backgrounds but so steap spectrum!

32. Atmospheric m is strongly attenuated… Up Down TAUP 2003

33. Flux as a function of energy deposit in km3 • dE/dX~bE DE~DXbE

34. Atmospheric m is strongly attenuated… Up Down TAUP 2003

35. Intensity of EHE m and t [cm-2 sec-1] TAUP 2003

36. How EHE events look like Eµ=10 TeV ≈ 90 hits Eµ=6 PeV ≈ 1000 hits The typical light cylinder generated by a muon of 100 GeV is 20 m, 1PeV 400 m, 1EeV it is about 600 to 700 m.

37. t/mappeared in 10 PeV- EeV are our prime target on GZK n detection. 1/100-1/500 of primary n intensity! Downwardt and m make main contributions in PeV -EeV Energy Estimation would be a key for the bg reduction Because atmospheric m spectrum ~ E3.7 TAUP 2003 Summary GZK n is DETECTABLE by IceCube 0.2-40 events/year (BG 0.05 events/year)