1. introduction 2. icecube detector 3. neutrino detection principles 4. status of the construction...
TRANSCRIPT
1. Introduction2. IceCube Detector3. Neutrino Detection Principles4. Status of the Construction and Performance5. Summary
IceCubeneutrino telescope@SouthPole
- a new window on the universe
Joanna Kiryluk LBNL/UC Berkeley
UHE
Cosmic Rays
€
p+ γ → Δ → π + n→ ...GZK cutoffGreisen, ZatsepinAnd Kuzmin (1966)
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
What’s the origin of Cosmic Rays with E up to 1020 eV ?The puzzle unresolved almost a century after CR discovery
?SNR
- do not point back to the source
protons: directions scrambled by magnetic
fields -rays : straight-line
propagation
Multi-Messenger AstronomyWhere do UHE cosmic rays come from?
protons, -rays & neutrinos as probes of the high-energy Universe
- do not point back to the source
but reprocessed in the sources (difficult to prove that they are associate with CR); extragalactic backgrounds absorb E>TeV
Multi-Messenger AstronomyWhere do UHE cosmic rays come from?
protons, -rays & neutrinos as probes of the high-energy Universe
protons: directions scrambled by magnetic
fields -rays : straight-line
propagation
Neutrinos:Neutrinos: straight-line propagation, unabsorbed, but difficult to detect
Expected n flux from galactic point sources, example SNR: RXJ 1713-3946
Christian Stegmann et al. , J.Phys.Conf.Serv.60 (2007) 243
€
p+ γ → n + π +
€
π → μ+υμ
→ {e + υ μ + υ e} + υ μ
cosmic rays interact with the microwave
background
cosmic rays disappear, neutrinos appear
NeutrinosfromGZKinteractions
Expect ~ 1 event per km2 per year
GZK neutrinos - very low but guaranteed flux (GZK CRs exist!)
(Ultra-) high-energy neutrino detectors
Neutrino telescopes:Primarily aimed at > TeV μ, e.g. IceCube /AMANDA, Antares … Also sensitive to PeV, EeV , but limited area
New directions with effort to detect:Giant air showers detectors sensitive to ~EeV e.g. AugerRadio detection - threshold in EeV range , e.g. Anita
Extraterrestrial neutrinos - discovery potential!
The only confirmed extraterrestrial low energy neutrino sources detected so far are the Sun and the supernova SN1987A
USA: Bartol Research Institute, Delaware Pennsylvania State University UC Berkeley UC Irvine Clark-Atlanta University University of Maryland IAS, Princeton University of Wisconsin-Madison University of Wisconsin-River Falls Lawrence Berkeley National Lab. University of Kansas Southern University and A&M
College, Baton RougeUniversity of Alaska, Anchorage
Sweden: Uppsala Universitet Stockholm Universitet
UK: Imperial College,
London Oxford University
Netherlands: Utrecht University Belgium:
Université Libre de Bruxelles
Vrije Universiteit Brussel Universiteit Gent Université de Mons-Hainaut
Germany: Universität Mainz DESY-Zeuthen Universität Dortmund Universität Wuppertal Universität Berlin MPI Heidelberg RWTH Aachen
Japan: Chiba university
New Zealand: University of
Canterbury
THE ICECUBE COLLABORATION
33 institutions, ~250 members http://icecube.wisc.edu
ANTARCTICAAmundsen-Scott Station
Science potential with IceCube is vast:
Neutrino point source search (μ Diffuse searches ( e, μ and more sensitive if there are more sources
IceCube physics topics
Atmospheric neutrinos Cosmic Ray (C.R.) composition Supernova (SN) Gamma Ray Bursts Search for exotic particles and new physics.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
http://www.sciencemag.org/content/vol315/issue5808
Vol 315 (2007)
The IceCube Detector
Counting House
1450 m
2450 m
AMANDA
IceTop Surface air shower array
InIce 70+ strings, each with 60
digital optical modules (DOM)
17 m between modules
125 m string separation
Instrumenting 1km3 of Antarctic Iceto detect extraterrestrial neutrinos
IceCube will detect neutrinos of all flavors at energies from 1011 eV to 1020 eV
Digital Optical Module (DOM)
DOM - a complete data acquisition system: - internal digitization and time stamping the photonic signals from the PMT- can perform PMT gain and time calibration- transmitting digital data to the surface
PMT
MainBoard
Main Board (most of electronics)- PMT output collected with fast waveform digitizer chips that sample the signal 128 times at 200-700 MSPS - PMT signal is fed into 3 parallel 10-bit ADC with a nominal gain ratios 0.25:2:16. Combined they provide wide dynamic range from single p.e. to thousands p.e.
Time Resolution from LED flashers
Method: flash an LED on a DOM and measure the arrival time of light reaching a nearby DOM
RMS variation of time delay measured with flashers for 59 DOM pairs on one string.
For most of the DOMs resolution better than 2 ns
DOM 51
DOM 52
DOM 53
DOM 54
Photon arrival time delay at DOM 52 when DOM 53 is flashing.
Muon neutrino Electron neutrino
Phototubes
(km long) Track:
+ increased detection volume
+ μ points along μ, i.e. to source
- cosmic ray μ background
- ok energy measured
Cascade: e-m or hadronic showers -must be in detector- μ background (brems’ng)- limited pointing capability + good energy measurement
Neutrinos: How do we see them?
Energy Res. : log(E)~0.3Angular Res.: 0.8 -2 deg
Neutrinos Signature (Simulations)
QuickTime™ et undécompresseur TIFF (non compressé)
sont requis pour visionner cette image.
E = 375 TeV
Energy Res. log(E)~0.1-0.2Poor Angular Resolution
QuickTime™ et undécompresseur TIFF (non compressé)
sont requis pour visionner cette image.300m
+N+...
+hadrons
Muon neutrino Electron neutrino Tau neutrino
a) Eµ=10 TeV ~ 90 hits
b) Eµ=6 PeV ~1000 hits
E = 10 PeV
Double-bang signature above ~ 1 PeVVery low backgroundPointing capability
E ~ dE/dx, E> 1 TeV
Origin of the neutrinos observed in the detector
M.Kowalski [astro-ph/0505506]
atmospheric neutrinos (mostly μ) dN/dE~E-3.7
neutrinos from charm decayIn the atmosphere dN/dE~ E-2.8
astrophysical neutrinos dN/dE~E-2.0 (model)
signal
Extraterrestrial Neutrinos: Signals and backgrounds
Low energy: Distinguish: - μ (CR vs ) by their direction- (atmospheric vs extrater.) by energy
Above 105 TeV - small μ and bg produced in CR interactions with the Earth atmosphere.
Distinguish flavor by their topology
High energy:
Neutrinos (all flavors) interact in(or close to) the detector via:Muon channel:
Cascade channel:
€
e(τ ) + N → e(τ ) + X (CC)ν e(μ ,τ ) + N →ν e(μ ,τ ) + X (NC)
€
μ + N → μ + X (CC)
AMANDA
IceCube
Skiway
Amundsen-Scott South Pole Station
Geographic South Pole
IceCube at the South Pole
Drill Site Counting House
Getting there is half the fun
New C-17 Old C-141 (photo by RGS)
Transportation upgrades to Antartica….
Schedule and Logistics
The new South-Pole station
Can work from December to mid-February Logistics are a huge concern Power - expensive! 3 winterover scientists operate and maintain instrument during winter Weather is always a factor
Field team deals very well with issues and harsh conditions
Hotwater drill system
Drill tower
Hose reel
DOMs
Hole Drilling
Design goal: 40 hours to drill a hole
36 h
Successfully used for three holes. Expected to save about 2 holesper season.
2007: Independent firn drillD
ep
th (
m)
Time
2500 m deep, 60 cm dia. holes 5 Megawatt hot water drill Speeds to 2.2 m/minute
IceCube Deployments to Date AMANDA
21
3029
40
50
3938
49
59
4647
48
5857
6667
74
65
73
78
56
72
2004-2005
1 string deployedFirst dataastro-ph/0604450
2005-2006
8 string deployed
2006-2007
13 strings deployed
1+8+13 = 22 strings to dateGoal >=14 strings/season
Completion by 2011.
More than 25 % of full detector installed.
1424 sensors deployed, and 1403 sensors (98.5%) are commissioned and being used
Comparison to AMANDA-II: 85 of 677 sensors (12.5%) are not usable for technical reasons
April 29 2007 (commissioning)
IceDust layer (low rate)
2007 13-strings Deployment Physics Run - started May 2007 Updated DAQ, triggers, monitoring system
1450m 2450m 0 50m
Measurements: in-situ light sources, atmospheric muons and Dust Loggers (records dust layers with cm resolution):
Ice Properties: scattering and absorption
Average optical ice parameters:
Dust Logger signal
depth (m)
depth (m)D
OM
Occ
upan
cy
abs~110m@400nmsca~ 20m@400 nm
Scattering length varies from 6 to 30m depending on depth and location of dust layers (deposited by e.g. volcanic events over past thousands of years)
Understanding ice properties - key to modeling IceCube
Probability a DOM is hit in evts that have >7 hits on a string
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Dust Logger
QuickTime™ and aH.264 decompressor
are needed to see this picture.
Bubble Camera - 2007 deployment
DOM 60
Weight Stack
Sphere 1
Sphere 2
String 57
Particle (μ) Tracking
Charged particles emit Cherenkov radiation angle = Cos-1(1/n) = 410
The photons scatter (L ~ 25 m) Some (<10-6) photons are observed in photodetectors We measure points 0-30 meters from the μ track Angular resolution < 10 for long tracks
μNoise
€
μ + N → μ + X
bremsstrahlung
pair-creation
e+e-
πphoto-nuclear
μ tracks lose energy by emitting , e+e- pairs and hadronic interactions (via virtual )
DOM
Atmospheric muon neutrinos in 2006 2006 data: 90 days with 9 stringsData selection done online at S. Pole and transferred by satellite North
Neutrino-induced muon candidate
Dust layer
IC-9strings (first) analysis: Atmospheric muon neutrinos in 2006
Reconstructed Zenith Angle (deg)
Contamination at the horizon likely due to mis-reconstructed events (single shower) as being below the horizon.
After cuts: 234 events measured (211 expected from atm. MC) Reconstructed direction
Reconstructed Azimuth Angle (deg)
Horizon
arXiv:0705.1781 [astro-ph]
Event rate: 610 Hz Raw data: 180 GB/day Uptime to date: 92% Events recorded by June 28, 2007 1.65 x 10^9 Continuous data taking …
Sufficient data to observe (diffuse) non-atmospheric neutrinos?
IC-22 run statusMay 23, 2007 - start of IceCube science run
Downgoing muons (background) Azimuth distribution illustrates
detector response.
String Commissioning
pDAQ IC36+Commissioning(95%)
Calibration(Geometry, DOMs)
P&F IC36+Commissioning
Dec Jan Feb Mar April
IC22 Science run IC36+ Science run
IC 36+ verification
FinishLatecomers
IC22 IC36+ Schedule
Current status: Ready to go….winterovers arrive on ice Oct 22!!Bulk of drillers arrive on Oct 31
Future Plans Above ~ 1016 eV, the expected rates in IceCube are small
A ~100 km3 detector is needed to see GZK Protons and have limited range. Only probe sensitive to ‘EHE universe’ > 50 megaparsecs away
Coherent radio and/or acoustic detection of EHE showers may allow for an affordable detector
Summary IceCube construction is well underway
- More than 25% complete.- Completed detector in 2011.
Physics analysis underway.IceCube IC-9 atmospheric muon neutrino resultsIC-22 analyses on-going
Stay tuned!
ANITA
ANITAGondola &
Payload
Antenna array
Overall height ~8m
Solarpanels
Antarctic Impulsive Transient Antenna Experiment
searching for GZK neutrinos with radio
detection in Antarctic iceneutrino
Cascade: ~10m length
air
Ice- radio transparent medium
RFCherenkov
Utilizes Askaryan effect
STATUS: 35 day flight this season 2006/7
~15 days of good data - Haven’t unblinded yet
- Might see a GZK neutrino, if luckyPayload was crunched on landing
Next flight in 2008/9
ARIANNA concept
100 x 100 station array, ~1/2 Teraton
~300m
Ross Ice Shelf, Antarctica
Sensitivity and limits
S. Barwick
ANITA sensitivity, 45 days total:~5 to 30 GZK neutrinos
IceCube: high energy cascades ~1.5-3 GZK events in 3 years
Oscar Blanch-Bigas
Neutrino fluxes - upper limits
Supernova Monitor
Amanda-II
IceCube
0 5 10 sec
Count rates
LMC
AMANDA II:95% of Galaxy
IceCube:Milky Way + LMC
msec time resolution
You are here
Data Acquisition and Trigger
“Full” DAQ software & triggerSelect time regions of interest using
multiplicity, topologyEvents == time windowCollect data for these windows
Data filtering (muon, cascade)Reconstruct eventsSelect interesting events for satellite
transmission
Monitoring, calibration, logging, control functions,…
Master Clock
Distribution
InIce