Document

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)
You cannot expect too many n!
pg
(p,n) p
2g
TeV/EGRET
observations !!
mn
enn
Cosmic Ray
observations!
Synchrotron
cooling
You cannot expect too high energies
Theoretical bounds
DUMAND test string
FREJUS
MACRO
opaque for neutrons
NT-200
MPR
neutrons can escape
Suppressed by
Synchrotron Cooling
W&B
Mannheim, Protheroe and Rachen (2000) – Waxman, Bahcall (1999)
 derived from known limits on extragalactic protons + g-ray flux
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
Shall we Dance?
Where are we ?
South Pole
Dome
AMANDA
1500 m
Summer camp
Amundsen-Scott South Pole Station
2000 m
[not to scale]
AMANDA-B10
(inner core of AMANDA-II)
10 strings
302 OMs
Data years: 1997-99
AMANDA-II
19 strings
677 OMs
“Up-going”
“Down-going”
(from Northern sky)
(from Southern sky)
Trigger rate: 80 Hz
Data years: >=2000
Optical Module
PMT noise: ~1 kHz
PMT looking downward
Event detection in the ice
O(km) long m tracks
South
Pole ice: by
event
reconstruction
the most transparent natural
Cherenkov light timing
medium ?
~15 m
AMANDA-II
m tracks
cascades
<labs> ~ 110 m @ 400 nm
pointing error :
1.5º - 2.5º
<lsca> ~ 20 m @ 400 nm
σ[log10(E/TeV)] :
0.3 - 0.4
2p
coverage :
Cascades (particle showers)
a neutrino telescope
Qmn0.65o(En/TeV)-0.48
(3TeV<En<100TeV)
pointing error :
30º - 40º
σ[log10(E/TeV)] :
0.1 - 0.2
coverage :
4p
cosmic rays (+SPASE)
combined pointing err : < 0.5º
Longer absorption length → larger effective volume
σ[log10(E/TeV)] :
0.06 - 0.1
Nucl. Inst. Meth. A 524, 169 (2004)
Atmospheric n's in
AMANDA-II
 neural network energy reconstruction
 regularized unfolding
measured atmospheric neutrino spectrum
 spectrum up to 100 TeV
 compatible with Frejus data
1 sigma energy error
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 n‘s
Oscillation in AMANDA‘s range
SuperK values:
Dm² = 2,4 * 10-3 eV²
1 TeV
sin²(2QMix) = 1,0
100 GeV
P( nm  nm )
50 GeV
30 GeV
Problem: lower
energy threshold
~ 100 GeV - 1 TeV
10 GeV
positive
identification
not possible
flight length / km
110°
180°
Oscillation in AMANDA‘s range
Variation of Dm² (En =100GeV)
10-3 eV²
significant
oscillation
in
AMANDA‘s
range
P( nm  nm )
2,4 * 10-3 eV²
10-2 eV²
exclusion
regions in
sin²(2Q)-Dm²
-plane
2,8 * 10-2 eV²
flight length / km
110°
180°
Excess of cosmic
neutrinos? Not yet ...
talk HE 2.3-4
.. 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 !
The highest energy event (~200 TeV)
300 m
Theoretical bounds and
future
DUMAND test string
FREJUS
MACRO
opaque for neutrons
NT-200
AMANDA-97
AMANDA-00
MPR
neutrons can escape
NT-200+
AMANDA-II
W&B
IceCube
Mannheim, Protheroe and Rachen (2000) – Waxman, Bahcall (1999)
 derived from known limits on extragalactic protons + g-ray flux
n telescope : point source search
Maximum significance 3.4 s
compatible with atmospheric n
Preliminary
2000-2003
3369 n from northern hemisphere
3438 n expected from atmosphere
 also search for neutrinos from unresolved sources
Search for clustering in northern hemisphere
• compare significance of local fluctuation to
atmospheric n expectations
~92%
• un-binned statistical analysis
• no significant excess
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
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 extragalactic 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), 738-743
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!)
Search for nm 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
Low background
analysis due to
space and time
coincidence!
(Start of T90 )
PRELIMINARY
GRB catalogs:
BATSE, IPN3 & GUSBAD
Analysis is blind:
finalized off-source (± 5 min)
with MC simulated signal
BG stability required within ± 1
hour
Year
Detector
NBursts
NBG, Pred
NObs
Event U.L.
1997
B-10
78 (BT)
0.06
0
2.41
1998
B-10
94 (BT)
0.20
0
2.24
1999
B-10
96 (BT)
0.20
0
2.24
2000
A-II
44 (BT)
0.83/0.40
0/0
1.72/2.05
(2 analyses)
97-00
B-10/A-II
312 (BT)
1.29
0
1.45
2000
A-II
24 (BNT)
0.24
0
2.19
2000
A-II
46 (New)
0.60
0
1.88
2000
A-II
114 (All)
1.24
0
1.47
Muon effective area (averaged over
zenith angle)  50,000 m2 @ PeV
97-00 Flux Limit at Earth*: E2Φν≤ 4·10-8 GeV cm-2 s-1 sr-1
(BT = BATSE Triggered
*For
BNT = BATSE Non-Triggered
New = IPN & GUSBAD)
312 bursts w/ WB Broken Power-Law Spectrum (Ebreak= 100 TeV, ΓBulk= 300)
WIMP annihilations in the center of
Earth
Sensitivity to muon flux from neutralino
annihilations in the center of the Earth:
xx  qq, l  l - , W, Z, H n m
Muon flux limits
Look for vertically upgoing tracks
NN optimized (on 20% data) to
- remove misreconstructed atm. μ
- suppress atmospheric ν
- maximize sensitivity to WIMP signal
Eμ > 1 GeV
Combine 3 years: 1997-99
Total livetime (80%): 422 days
No WIMP signal found
Limit for “hardest” channel:
xx  τ  τ - n m
xx  W  W- n m
M x  50 GeV
M x  100- 5000 GeV
Disfavored by
direct search
(CDMS II)
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
No WIMP signal found
Best sensitivity (considering livetime)
of existing indirect searches using
muons from the Sun/Earth
Muon flux limits
Eμ > 1 GeV
AMANDA as supernova monitor
~MeV
AMANDA-II
Bursts of low-energy (MeV) νe from SN
AMANDA-B10
► simultaneous increase of all
PMT count rates (~10s)
Since 2003:
SNDAQ includes all AMANDA-II channels
IceCube
30 kpc
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
The IceCube Neutrino
Telescope
Project overview and Status
EHE Physics Example: Detection of
GZK neutrinos
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
1200 m
IceTop
IceTop
160 tanks
frozen-water tanks
2 OMs / tank
First year deployment (Jan 2005)
4 IceCube strings (240 OMs)
8 IceTop Tanks (16 OMs)
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
Road to South Pole
9 hours
6 hours
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
Digital Optical Module (DOM)
HV Base
“Flasher Board”
Main Board
(DOM-MB)
10” PMT
13” Glass
(hemi)sphere
Capture Waveform
information (MC)
String 1
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
String 2
String 3
String 4
nt
E=10 PeV
String 5
World-wide DOM
collaboration
Stockholm
LBL
Electronics
Wisconsin
Assembly
Calibration
DESY
Assembly
Calibration
Chiba
Calibration
Screening.
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.; insitu gain calibration)
Notes:
•
•
Only Hamamatsu PMT
meets excellent low noise
rates!
Tested three flavors of
R7081.
SPE Charge Spectrum
Setup photo
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
IceCube Software
CORSIKA
JULIeT
Photonics
MMC/NuSim
ROMEO
DOM Sim
ROMEO – Optical detector simulator
ROOT Ttask base
Full detector simulation
JULIeT – Particle Propagator
Monte-Carlo
Simulation
m, t ,n
Numerical Calculation
Angular resolution as a function of zenith angle
0.8°
0.6°
 above 1 TeV, resolution ~ 0.6 - 0.8 degrees for most zenith angles
Energy Spectrum Diffuse
Search
Blue: after downgoing muon rejection
Red: after cut on Nhit to get ultimate sensitivity
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.
Right now at the pole
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
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-
Products
ne
ne
nm
nt
e/g
m
Weak
nm
Weak
Weak
Weak
Weak
Cascades
e/g
t
p
p
Weak
nt
m
t
Decay
Decay
Weak
Decay
Decay
Pair/decay
Pair
Bremss
Decay
Weak
Pair
Bremss
Decay
Decay
Pair
Pair
Pair
PhotoNucl.
Decay
PhotoNucl.
Cascades
Upward-going
Downward going!!
Atmospheric muon! – a major backgrond
But so steep spectrum
HEAPA 2004
Down-going events dominate…
Atmospheric m is strongly attenuated…
11000m
Up
Down
2800 m
1400 m
HEAPA 2004
Flux as a function of
energy deposit in km3
dE/dX~bE
DE~DXbE
Uncertainty in Prompt Lepton
Cross Sections
• The uncertainty ~3 orders
AMANDA II
(neutrinos)
ZhVd
• Need for accelerator data
extrapolation
• Crossover between 40TeV
and 3 PeV
Constraining Charm Neutrino models
by analysis of downgoing Muon Data
AMANDA II
(neutrinos)
• Very preliminary sensitivity
on ZHV-D model
ZHVd
• Systematics
understood
AMANDA II
(muons)
to
be
well
• Potential to set a more
restrictive limit than neutrino
diffuse analyses
IceCube EHE n Sensitivity
90% C.L. for 10 year observation
Published in Phys. Rev. D
S.Yoshida, R.Ishibashi, H,Miyamoto, PRD 69 103004 (2004)
IceTop : EeV detection
Incident cosmic-ray
nucleus
n
m
Penetrating muon bundle
in shower core
Threshold ~ 1018 eV
to veto this background
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
Grand Summary
RICE
Fly‘s Eye
Frejus
Macro
Baikal
Amanda-B
AGASA
NT-214
AMANDA-II
& ANTARES
AUGER nt
IceCube
& km3 in sea
OWL, EUSO
Courtesy: Learned & Mannheim; Spiering

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