first-generation neutrino telescopes

1. first-generation neutrino telescopes

2. Infrequently, a cosmic neutrino is captured in the ice, i.e. the neutrino interacts with an ice nucleus • In the crash a muon (or electron, • or tau) is produced Cerenkov light cone muon or tau interaction Detector • The muon radiates blue light in its wake • Optical sensors capture (and map) the light neutrino

3. 50 m size perspective

4. Optical module 1996-2000 AMANDA II Amundsen-Scott Station South Pole

5. South Pole AMANDA– 1 mile deep

6. Building AMANDA Drilling Holes with Hot Water The Optical Module

7. Christchurch, New Zealand International Antarctic Center

8. Logistics simple!

9. thedome the new station

12. Building AMANDA

15. AMANDA II t i me • up-going muon • 61 modules hit > 4 neutrinos/day on-line size ~ number of photons

16. AMANDA Event Signatures:Muons CC muon neutrino Interaction  track nm + N  m +X

17. 200 TeV e two events

18. Maximum Likelihood method Take into account time profiles of expected photon flight times Bayesian approach - use prior knowledge of expected backgrounds and signals event reconstruction

19. Short track length = more likely to be background Quality parameters: Example 1: The track length

20. The smoothness is a measure of how regular the photon density is distributed along the track. A well reconstructed muon track is more likely to have a high smoothness. Quality parameters: Example 2: The smoothness High Low

21. A well reconstructed event has better agreement between a simple fit and a full likelihood reconstruction. Quality parameters: Example 3: The angular difference between 2 fits

22. Likelihood Zenith angle mismatch between two types of fits. Sphericity of Hits (Brem?) Track Length (is an energy cut, too) Smoothness of hits along the track Number of unscattered photons Combine 6 to a single event quality parameter. Only 3 for completed detector! Quality Parameters

23. quality cut

24. Atm. Neutrinos (): 60/day Atm. Muons: 8.6*106/day Atmospheric muons and neutrinos

25. vertically up horizontally Atmospheric Neutrinos, 97 data ~ 300 events  AMANDA sensitivity understood down to normalization factor of ~ 40% (modeling of ice ...)

26. Understanding Ice and Calibrating AMANDA • In situ light sources • Ice properties • Relative PMT timing, gain • Response to electromagnetic showers • crosstalk • Downgoing cosmic-ray muons • Relative PMT timing, gain • AMANDA-SPASE coincidences • Directionality • Ice properties • Atmospheric neutrinos • Full detector response

27. d=32 m d  17 m 6 m 3 50 200 400 700 muon delay, nsec Amanda: time delay due to scattering

28. Ice Properties • Most challenging initial problems now understood using in situ lasers and LEDs • Disappearance of bubbles • Mapping of dust layers • scatter :6 m - 52 m • abs : 9 m - 240 m

32. Sensitivity to up-going muons demonstrated with CC atm. nm interactions: Sensitivity to cascades demonstrated with in-situ sources (see figs.) & down-going muon brems. AMANDA Is Working Well: 4 nus per day! Data MC 290 atm. nm candidates (2000 data) In-situ light source Simulated light source Horizontal Up-going Zenith • AMANDA also works well with SPASE: • Calibrate AMANDA angular response • Do cosmic ray composition studies.

33.  effective area (schematic): -interaction in earth, cuts 2 -5m2 En 2 3 cm2 100 GeV 100 TeV 100 PeV Detector capabilities •  muons: • directional error: 2.0 - 2.5° • energy resolution:¶0.3 – 0.4 • coverage: 2 •  primary cosmic rays:(+ SPASE) • energy resolution:¶0.07 – 0.10 •  „cascades“: (e±,  , neutral current) • zenith error: 30 - 40° • energy resolution:¶ 0.1 – 0.2 • coverage: 4 ¶[log10(E/TeV)]

34. AMANDA-II Antarctic Muon And Neutrino Detector Array • Construction began in 1995 (4 strings) • AMANDA-II completed in 2000 (19 strings total) • 677 optical modules • 200 m across • ~500 m tall (most densely instrumented volume)

35. Construction began in 1995 (4 strings) • AMANDA-II completed in 2000 (19 strings total) • 677 optical modules • 200 m across • ~500 m tall (most densely instrumented volume) The AMANDA detector

36. Slant Depth Binning  zenith angle cos θ 1 2 3 4 5 1730m 6 7 8 8650m Slant Depth

37. Required background rejection

38. Atmospheric muons in AMANDA-II Atmospheric muons and neutrinos: AMANDA‘s test beams much improved simulation ...but data 30% higher than MC ...  normalize to most vertical bin Systematic errors: 10% scattering ( 20m @ 400nm) absorption (110m @ 400nm) 20% optical module sensitivity 10% refreezing of ice in hole PRELIMINARY threshold energy ~ 40 GeV (zenith averaged)

39. Down-going Muon Flux depth zenith angle

40. Atmospheric n’s as Test Beam Neutrino energy in GeV

41.  spectrum up to 100 TeV  compatible with Frejus data presently no sensitivity to LSND/Nunokawa prediction of dip structures between 0.4-3 TeV In future, spectrum will be used to study excess due to cosmic ‘s Atmospheric n's in AMANDA-II neural network energy reconstruction regularized unfolding PRELIMINARY measured atmospheric neutrino spectrum 1 sigma energy error

42. talk HE2.1-13 for QGSJET generator: (H) = 2.70 ± 0.02 0 (H) = 0.106(7) m-2s-1sr-1TeV-1 Compatible and competitive () with direct measurements Cosmic Ray flux measurement In some cases ice and OM-sensitivity effect can be circumvented ... (E)=0E- empirical separation of ice and OM sensitivity effects PRELIMINARY

43. South Pole Air Shower Experiment (SPASE) AMANDA-II: 200 x 500 cylinder + 3 1km strings, running since 2000 South Pole Dark sector Skiway AMANDA Dome IceCube

44. talk HE 1.1-25 iron AMANDA (correlate to #muons) proton log(E/GeV) SPASE-2 (correlated to #electrons) robust evidence for composition change around knee ... cosmic ray composition studies SPASE-2 (electronic component) - AMANDA B10 (muonic component) - unique combination! AMANDA II

45. talk HE 1.1-25 blue band: detector and model uncertainties red band: uncertainty due to low energy normalization confirms trend seen by other experiments ... Composition change around „knee“ 1015 eV 1016 eV A=30 A=6 publication in preparation 1998 data

46. 1 km 2 km Cosmic ray composition SPASE air shower array preliminary

47. 10-14 10-15 10-16 10-17 10-18 0.50 0.75 1.00  = v/c Relativistic Magnetic Monopoles Soudan KGF Baikal MACRO Orito C - light output  n2·(g/e)2 upper limit (cm-2 s-1 sr-1) Amanda  electrons n = 1.33 (g/e) = 137/ 2 IceCube  8300

48. Excess of cosmic neutrinos? .. for now use number of hit channels as energy variable ... muon neutrinos (1997 B10-data) Electron + tau (2000 data) „AGN“ with 10-5 E-2 GeV-1 cm-2 s-1 sr-1 cuts determined by MC – blind analyses !

49. cascades (2000 data) Excess of cosmic neutrinos? Not yet... .. for now use number of hit channels as energy variable ... muon neutrinos (1997 B10-data) „AGN“ with 10-5 E-2 GeV-1 cm-2 s-1 sr-1 cuts determined by MC – blind analyses !

50. Expected sensitivity 2000 data: ~ 310-7 GeV-1 cm-2 s-1 sr-1 Diffuse flux muon neutrinos Note that limits depend on assumed energy spectrum ... 3·103 – 106 GeV: E2(E) < 8 10-7 GeV-1 cm-2 s-1 sr-1 prel. 2.5 ·106 – 5.6 ·108 GeV: E2(E) < 7.2 10-7 GeV-1 cm-2 s-1 sr-1 AMANDA II (with 3 years data): ~ 10 X higher Sensitivity