TAUP 2003 Ice Cube Neutrino Telescope and the

TAUP 2003 Ice. Cube Neutrino Telescope and the GZK n detection Shigeru Yoshida, Chiba University

The Ice. Cube Collaboration Institutions: 11 US, 9 European institutions and 1 Japanese institution; ≈150 people 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 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, 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, 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, Belgium

South Pole Dark sector Skiway AMANDA Dome Ice. Cube

Ice. Cube Ice. Top AMANDA South Pole Skiway 80 Strings 4800 PMT Instrumented volume: 1 km 3 (1 Gt) Ice. Cube is designed 1400 m to detect neutrinos of all flavors at energies from 107 e. V (SN) to 1020 e. V 2400 m

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

Capture Waveform information (MC) ATWD 300 MHz String 1 14 bits. 3 different gains (x 15 x 3 x 0. 5) Capture inter. 426 nsec 10 bits FADC for long duration pulse. Events / 10 nsec 0 - 4 µsec String 2 String 3 String 4 E=10 Pe. V String 5

Photomultiplier: Hamamatsu R 7081 -02 (10”, 10 -stage, 1 E+08 gain) • Selection criteria (@ -40 °C) • • Noise < 300 Hz (SN, bandwidth) Gain > 5 E 7 at 2 k. V (nom. 1 E 7 + margin) P/V > 2. 0 (Charge res. ; insitu gain calibration) Notes: • • Only Hamamatsu PMT meets excellent low noise rates! Tested three flavors of R 7081.

N

Digital Optical Module (DOM) Main Board Test Card

SPE Discriminator Scan – PMT Pulses Input (71 DB)

The big reel for the hotwater drill

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

Aeff / km 2 Effective area of Ice. Cube 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)

In three years operation… TAUP 2003 E 2 d. Nn/d. E ~10 -8 Ge. V/cm 2 s sr (diffuse) E 2 d. Nn/d. E ~7 x 10 -9 Ge. V/cm 2 s (Point source) 200 bursts in coincidence n(GRBs – WB o i t flux) c e t e d s 5 r o F

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

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/Ice. Top 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.

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

UHE (Ee. V or even higher) Neutrino Events Arriving Extremely Horizontally • Needs Detailed Estimation • Limited Solid Angle Window (sr. NA)-1 ~ 600 (s/10 -32 cm 2) -1(r/2. 6 g cm-3) -1 [km] Involving the interactions generating electromagnetic/hadron cascades N X e+e- TAUP 2003

Products ne ne n nt e/g Weak t p Weak e/g p Weak nt t Weak n Incoming Weak Cascades Decay Weak Pair/decay Pair Bremss Decay Weak Pair Bremss Decay Pair Photo. Nucl. Decay Photo. Nucl. Cascades

TAUP 2003

Muon(Neutrinos) from n nt Nadir Angle TAUP 2003

Tau(Neutrinos) from n Suppression By t decay TAUP 2003 nt

GZK Neutrino Production p E = 10 20 e. V γ π＋ n ＋ μ ν e ＋ γ ν p E ~ 0. 8 x 10 20 e. V 0. 6 x 10 -27 cm 2 2. 725 K 411 photons / cm 3 Conventional Mechanism of EHE neutrinos!!

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

Upward-going TAUP 2003

Downward going!! TAUP 2003

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

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

Intensity of EHE and t [cm-2 sec-1] GZK I (E>10 Pe. V) It(E>10 Pe. V) model RATE [/yr/km 2] m=4 Zmax=4 Down 5. 90 10 -19 5. 97 10 -19 0. 37 Up 3. 91 10 -20 6. 63 10 -20 0. 03 Down 8. 88 10 -17 9. 10 10 -17 53. 4 Up 5. 72 10 -19 9. 73 10 -18 4. 64 m=7 Zmax=5 TAUP 2003

Atmospheric Muons! Major Backgrounds but so steap spectrum!

Atmospheric is strongly attenuated… Up TAUP 2003 Down

Flux as a function of energy deposit in km 3 d. E/d. X~b. E DE~DXb. E

Atmospheric is strongly attenuated… Up TAUP 2003 Down

Intensity of EHE and t [cm-2 sec-1] GZK model I (E>10 Pe. V) It(E>10 Pe. V) Energy Deposit RATE [/yr/km 2] m=4 Zmax=4 Down 4. 75 10 -19 2. 94 10 -19 0. 24 Atm m 1. 74 10 -19 0. 05 7. 21 10 -17 4. 83 10 -17 37. 9 m=7 Zmax=5 Down TAUP 2003

How EHE events look like The typical light cylinder generated by a muon of 100 Ge. V is 20 m, 1 Pe. V 400 m, 1 Ee. V it is about 600 to 700 m. Eµ=10 Te. V ≈ 90 hits Eµ=6 Pe. V ≈ 1000 hits

TAUP 2003 Summary t/ appeared in 10 Pe. V- Ee. V are our prime target on GZK n detection. 1/100 -1/500 of primary n intensity! Downward t and make main contributions in Pe. V -Ee. V Energy Estimation would be a key for the bg reduction Because atmospheric spectrum ~ E 3. 7 GZK n is DETECTABLE by Ice. Cube 0. 2 -40 events/year (BG 0. 05 events/year)