1. The AMANDA and IceCube 高エネルギーν天文学：宇宙探査の窓
Physics Motivation
AMANDA detector
Recent Experimental Results
IceCube Project overview and Status
EHE Physics Example: Detection of GZK neutrinos
吉田　滋 (千葉大学理)

2. You cannot expect too many n!
p g (p,n) p 2g
TeV/EGRET
observations !!
Cosmic Ray
observations!
m n
Synchrotron
cooling
e n n
You cannot expect too high energies

3. Theoretical bounds Suppressed by Synchrotron Cooling MPR W&B
DUMAND test string
FREJUS
NT-200
MACRO
opaque for neutrons
MPR
neutrons can escape
atmospheric 
W&B
Mannheim, Protheroe and Rachen (2000) – Waxman, Bahcall (1999)
 derived from known limits on extragalactic protons + -ray flux

4. EHE(Extremely HE) n Synchrotron cooling of m …
Production sites with low B
Intergalactic space!!
GZK Production
Z-burst
Topological Defects/Super heavy Massive particles

5. Shall we Dance?

6. Amundsen-Scott South Pole Station
Where are we ?
South Pole
Dome
road to work
AMANDA
Summer camp
1500 m
Amundsen-Scott South Pole Station
2000 m
[not to scale]

7. AMANDA-B10 10 strings 302 OMs AMANDA-II 19 strings 677 OMs
(inner core of AMANDA-II)
10 strings
302 OMs
Data years:
AMANDA-II
19 strings
677 OMs
Trigger rate: 80 Hz
Data years: >=2000
“Up-going”
(from Northern sky)
“Down-going”
(from Southern sky)
Optical Module
PMT looking downward
PMT noise: ~1 kHz

8. Event detection in the ice
O(km) long m tracks
South Pole ice:
the most transparent natural
medium ?
event reconstruction by Cherenkov light timing
~15 m
<labs> ~ nm
<lsca> ~ nm
AMANDA-II
m tracks
pointing error : º - 2.5º
σ[log10(E/TeV)] :
coverage : p
Cascades (particle showers)
pointing error : º - 40º
σ[log10(E/TeV)] :
coverage : p
cosmic rays (+SPASE)
combined pointing err : < 0.5º
σ[log10(E/TeV)] :
Nucl. Inst. Meth. A 524, 169 (2004)
cascades
a neutrino telescope
Qmn0.65o(En/TeV)-0.48
(3TeV<En<100TeV)
Longer absorption length → larger effective volume

9. Atmospheric n's in AMANDA-II
 neural network energy reconstruction
 regularized unfolding
PRELIMINARY
measured atmospheric neutrino spectrum
 spectrum up to 100 TeV
 compatible with Frejus data
presently no sensitivity to LSND/Nunokawa
prediction of dip structures between TeV
In future, spectrum will be used
to study excess due to cosmic ‘s
1 sigma energy error
We can also say a few words about localy created nus
we have improvement compared to B10, better reco and energy measurement...sufficient statistics to do unfolding in statistically meaningfull way....

10. Oscillation in AMANDA‘s range
SuperK values:
Dm² = 2,4 * 10-3 eV²
sin²(2QMix) = 1,0
1 TeV
100 GeV
50 GeV
30 GeV
Problem: lower energy threshold
~ 100 GeV - 1 TeV
P( nm  nm )
10 GeV
positive identification not possible
flight length / km
110°
180°

11. Oscillation in AMANDA‘s range
Variation of Dm² (En =100GeV)
10-3 eV²
significant
oscillation in
AMANDA‘s
range
exclusion
regions in
sin²(2Q)-Dm²
-plane
2,4 * 10-3 eV²
10-2 eV²
P( nm  nm )
2,8 * 10-2 eV²
flight length / km
110°
180°

12. Excess of cosmic neutrinos? Not yet ...
talk HE 2.3-4
Excess of cosmic neutrinos? Not yet ...
.. for now use number of hit channels as energy variable ...
muon neutrinos (1997 B10-data)
accepted by PRL
cascades (2000 data)
„AGN“ with 10-5 E-2
GeV-1 cm-2 s-1 sr-1
cuts determined by MC – blind analyses !

13. The highest energy event (~200 TeV)
300 m

14. Theoretical bounds and future
DUMAND test string
FREJUS
NT-200
MACRO
opaque for neutrons
MPR
NT-200+
AMANDA-II
IceCube
AMANDA-97
AMANDA-00
neutrons can escape
atmospheric 
W&B
Mannheim, Protheroe and Rachen (2000) – Waxman, Bahcall (1999)
 derived from known limits on extragalactic protons + -ray flux

15. n telescope : point source search
Maximum significance 3.4 s
compatible with atmospheric n
~92%
Preliminary
3369 n from northern hemisphere
3438 n expected from atmosphere
Search for clustering in northern hemisphere
compare significance of local fluctuation to
atmospheric n expectations
un-binned statistical analysis
no significant excess
 also search for neutrinos from unresolved sources

16. Extend this information to the AMANDA exposure time, caveat:
g-rays observation are generally very short and for limited periods…
Tibet data quite cover the (HEGRA) High period
Second Assumption:
use X-ray data to define relative High/Low time for the whole time 2000/2003
AMANDA observational time High state/total time:
~210/807 or also
~1 year/4 years of AMANDA exposure

17. can be compared to our best upper limit (sensitivity shown here)
Low state:
can be compared to our best upper limit (sensitivity shown here)
about factor 2
Fit of the measured spectrum from HEGRA (Low)
Allowed range for the emitted flux
AMANDA sensitivity
Correction for extra-galactic g absorption¶:
TeV g-ray spectra are modified by red-shift dependent absorption by intergalactic IR-UV background
¶O.C.De Jager & F.W.Stecker, Astrophy.J. 566 (2002),

18. Current best estimate High state:
can be compared to the AMANDA sensitivity for ~ 200 days of live time (1 year exposure)
Sensitivity n/g~1 BUT without accounting for oscillations (a factor 2 in the n flux should be added!!)
Current best estimate
Fit of the measured spectrum from HEGRA (Low)
Allowed range for the emitted flux
AMANDA sensitivity (NB: this under the assumption that the source would show ~ 800 days of high state!)

19. Search for  correlated with GRBs
-1 hour
+1 hour
10 min
Blinded Window
Background determined on-source/off-time
Background determined on-source/off-time
Time of GRB (Start of T90 )
Low background analysis due to space and time coincidence!
PRELIMINARY
Year
Detector
NBursts
NBG, Pred
NObs
Event U.L.
1997
B-10
78 (BT)
0.06
2.41
1998
94 (BT)
0.20
2.24
1999
96 (BT)
2000
A-II
(2 analyses)
44 (BT)
0.83/0.40
0/0
1.72/2.05
97-00
B-10/A-II
312 (BT)
1.29
1.45
24 (BNT)
0.24
2.19
46 (New)
0.60
1.88
114 (All)
1.24
1.47
GRB catalogs:
BATSE, IPN3 & GUSBAD
Analysis is blind:
finalized off-source (± 5 min) with MC simulated signal
BG stability required within ± 1 hour
Muon effective area (averaged over zenith angle)  50,000 PeV
(BT = BATSE Triggered BNT = BATSE Non-Triggered New = IPN & GUSBAD)
97-00 Flux Limit at Earth*: E2Φν≤ 4·10-8 GeV cm-2 s-1 sr-1
*For 312 bursts w/ WB Broken Power-Law Spectrum (Ebreak= 100 TeV, ΓBulk= 300)

20. WIMP annihilations in the center of Earth
Sensitivity to muon flux from neutralino annihilations in the center of the Earth:
PRELIMINARY
Muon flux limits
Look for vertically upgoing tracks
Eμ > 1 GeV
NN optimized (on 20% data) to
- remove misreconstructed atm. μ
- suppress atmospheric ν
- maximize sensitivity to WIMP signal
Combine 3 years:
Total livetime (80%): 422 days
Disfavored by
direct search
(CDMS II)
Soft channel: b-bbar; Hard channel: WW pairs
New solar system WIMP diffusion model -> more realistic neutralino velocity distribution (Lundberg&Edsjoe)
Detection threshold (mu): ~50GeV (extrapolate to get limits for E>1 GeV)
No WIMP signal found
Limit for “hardest” channel:

21. WIMP annihilations in the Sun
Increased capture rate due to
addition of spin-dependent processes
Sun is maximally 23° below horizon
Search with AMANDA-II possible
thanks to improved reconstruction
capabilities for horizontal tracks
Exclusion sensitivity from
analyzing off-source bins
2001 data
0.39 years livetime
PRELIMINARY
Muon flux limits
Eμ > 1 GeV
IceCube best case = 10 calendar years, only atm nu bgr, no PMT noise
MESSAGE: at least for the Sun we have a chance to compete with direct searches
No WIMP signal found
Best sensitivity (considering livetime)
of existing indirect searches using
muons from the Sun/Earth

22. AMANDA as supernova monitor
AMANDA-II
AMANDA-B10
IceCube
30 kpc
AMANDA as supernova monitor
~MeV
Bursts of low-energy (MeV) νe from SN
► simultaneous increase of all
PMT count rates (~10s)
Since 2003:
SNDAQ includes all AMANDA-II channels
Recent online analysis software upgrades
can detect 90% of SN within 9.4 kpc
less than 15 fakes/year
 can contribute to
SuperNova Early Warning System
(with Super-K, SNO, Kamland, LVD, BooNE)
coverage
B10: 70% of Galaxy
A-II: 95% of Galaxy
IceCube: up to LMC
Analysis of 200X data
in progress

23. The IceCube Neutrino Telescope
Project overview and Status
EHE Physics Example: Detection of GZK neutrinos

24. Who are we ? Bartol Research Inst, Univ of Delaware, USA
Pennsylvania State University, USA
University of Wisconsin-Madison, USA
University of Wisconsin-River Falls, USA
LBNL, Berkeley, USA
UC Berkeley, USA
UC Irvine, USA
Univ. of Alabama, USA
Clark-Atlanta University, USA
Univ. of Maryland, USA
IAS, Princeton, USA
University of Kansas, USA
Southern Univ. and A&M College, Baton Rouge
Chiba University, Japan
University of Canterbury,
Christchurch, New Zealand
Universidad Simon Bolivar, Caracas,Venezuela
Université Libre de Bruxelles, Belgium
Vrije Universiteit Brussel, Belgium
Université de Mons-Hainaut, Belgium
Universität Mainz, Germany
DESY-Zeuthen, Germany
Universität Wuppertal, Germany
Uppsala Universitet, Sweden
Stockholm universitet, Sweden
Kalmar Universitet, Sweden
Imperial College, London, UK
University of Oxford, UK
Utrecht University, Utrecht, NL

25. First year deployment (Jan 2005) 4 IceCube strings (240 OMs)
IceTop
160 tanks
frozen-water tanks
2 OMs / tank
First year deployment (Jan 2005)
4 IceCube strings (240 OMs)
8 IceTop Tanks (16 OMs)
IceTop
IceCube
AMANDA
IceCube
80 strings
60 OMs/string
17 m vertical spacing
125 m between strings
IceTop Tank deployed in 2004
10” Hamamatsu R-7081

26. Road to South Pole
9 hours
6 hours

27. How EHE events look like
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.
Eµ=10 TeV ≈ 90 hits
Eµ=6 PeV ≈ 1000 hits

28. Digital Optical Module (DOM)
HV Base
“Flasher Board”
Main Board
(DOM-MB)
10” PMT
13” Glass (hemi)sphere

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

30. World-wide DOM collaboration
Stockholm
Electronics
Assembly
Calibration
Screening.
Wisconsin
LBL
DESY
Chiba

31. Photomultiplier: Hamamatsu R7081-02 (10”, 10-stage, 1E+08 gain)
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.

32. SPE Charge Spectrum

33. Setup photo
This is the actual picture of the setup. Laser, chamber, IceCube PMT, backward and forward monitor PMT, and the enegy meter.
(and Kotoyo and my hand)

34. Expected Data Rates PMT noise rate of 1 kHz is expected
"Scintillation" of glass introduces correlations!
Two DOMs/twisted pair ( $, kg, flights,...)
Rates/pair (bits/s) for coincidence mode
(with zero suppression and compression)
None: 18 kbytes/s x 2 x 10 = ~400 kbits/s
Soft: 6-8 kbytes x 2 x 10 = ~160 kbits/s
Hard: <1 kbyte/s x 2 x 10 = ~20 kbits/s
Demonstrated in the lab: 1 Mbit/s

35. IceCube Software

36. ROMEO – Optical detector simulator
ROOT Ttask base
Full detector simulation

37. JULIeT – Particle Propagator
Monte-Carlo Simulation m
, n
, t
Numerical Calculation

38. Angular resolution as a function of zenith angle
Waveform
information
not used.
Will improve
resolution for
high energies !
0.8°
0.6°
above 1 TeV, resolution ~ degrees for most zenith angles

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

40. HEAPA 2004
Project status
Startup phase has been approved by the U.S. NSB and funds have been allocated.
100 DOMs are produced and being tested this year.
Assembling of the drill/IceTop prototypes is carried out at the pole last season.
Full Construction start in 04/05 (this year!!); takes 6 years to complete.
Then 16 strings per season, increased rate may be possible.

41. Right now at the pole

42. GZK EHEn detection What is the GZK mechanism?
HEAPA 2004
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

43. mN mX e+e- 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-

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

45. Atmospheric muon! – a major backgrond But so steep spectrum
Upward-going
Downward going!!
Atmospheric muon! – a major backgrond
But so steep spectrum
HEAPA 2004

46. Down-going events dominate…
Atmospheric m is strongly attenuated…
11000m Up
Down
2800 m
1400 m
HEAPA 2004

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

48. Uncertainty in Prompt Lepton Cross Sections
AMANDA II
(neutrinos)
The uncertainty ~3 orders
Need for accelerator data extrapolation
Crossover between 40TeV and 3 PeV
ZhVd

49. Constraining Charm Neutrino models by analysis of downgoing Muon Data
AMANDA II
(neutrinos)
Very preliminary sensitivity on ZHV-D model
Systematics to be well understood
Potential to set a more restrictive limit than neutrino diffuse analyses
ZHVd
AMANDA II
(muons)

50. IceCube EHE n Sensitivity
90% C.L. for 10 year observation
Published in Phys. Rev. D
S.Yoshida, R.Ishibashi, H,Miyamoto, PRD (2004)

51. IceTop : EeV detection n m Threshold ~ 1018 eV to veto this background
Penetrating muon bundle in shower core
Incident cosmic-ray nucleus
Threshold ~ 1018 eV
to veto this background n
Potential to reject this background for EeV neutrinos by detecting the fringe of coincident horizontal air shower in an array of water Cherenkov detectors (cf. Ave et al., PRL 85 (2000) 2244, analysis of Haverah Park)
back

52. Grand Summary RICE Fly‘s Eye AGASA NT-214 AUGER nt OWL, EUSO Macro
Frejus
Baikal
Amanda-B
NT-214
AMANDA-II & ANTARES
AUGER nt
IceCube
& km3 in sea
OWL, EUSO
Courtesy: Learned & Mannheim; Spiering