IceCubea kilometer-scale deep-ice observatory
in Antarctica
Olga BotnerUppsala university, Sweden
Neutrino 2004, June 14-19, 2004
http
:// i
cecu
be.w
isc.
edu
http
:// i
cecu
be.w
isc.
edu
copyright ©West Nottinghamshire College 2003
The location – at the bottom of the world
Distance
from Paris
15440 km
and landing
Aerial View of the Amundsen-Scott Research Station
going there …
Photo http://www.ifa.hawaii.edu/~hsieh/
IceCube – a ”next generation” observatory
kilometer-scale successor to AMANDA
detection of Cherenkov light from the charged particles produced when a interacts with rock or ice
direction reconstructed from the time sequence of signals
energy measurement – counting the number deposited p.e. waveform read out
Expected performance wrt AMANDA increased effective area/volume superior angular resolution superior energy resolution
astronomy requires km-scale detectors astronomy requires km-scale detectors
ultrahigh energy ’s associated with the sources of
high energy cosmic rays top-down scenarios: decays of massive cosmological relics bottom-up scenarios: ”cosmic accelerators” accreting black holes (eg AGN) colliding neutron stars/black holes
fireball (eg GRB)
cosmogenic ’s supernova ’s dark matter WIMP, Kaluza-Klein exotica monopoles, Q-balls, mini black holes
p + (p or ) e ,
The Science
IceCube conceptDeep ice array 80 strings / 60 OM’s each 17 m OM spacing 125 m between strings hexagonal pattern over 1 km2
geometry optimized for detection of TeV – PeV (EeV) ‘s based on measured absorption
& scattering properties ofAntarctic ice for UV – blue
Cherenkov light
Surface array IceTop 2 frozen-water tanks (2 OM’s each) on top of every string
IceTop + IceCube: 1/3 km2 srfor coincident tracks
VETO against
All downward events E > 300 TeV with trajectories inside IceTop
Larger events falling outside
CALIBRATION
of angular response with tagged
Expect ~100 tagged air showers/day
with multi-TeV ’s in IceCube
Muon survey of IceCube
FY04:6
FY05:12FY06:16
FY07:16
FY08:16 FY09:14
Large showers with E ~ 100-1000 PeVwill clarify transition from galactic toextra-galactic cosmic rays
IceCube layout
Measure
energy spectrum
chemical composition
Measure
energy spectrum
chemical composition
Cosmic Ray physics
Showers triggering 4 stations give ~300 TeV threshold for EAS array
Showers triggering 4 stations give ~300 TeV threshold for EAS array
IceCube - Icetop coincidences
Investigate transition to
extragalactic CR
Investigate transition to
extragalactic CR
Small showers (2-10 TeV)associated with the dominant background detected as 2-tank coincidences at a station.
Small showers (2-10 TeV)associated with the dominant background detected as 2-tank coincidences at a station.
Energy range 1015 eV - 1018 eV
Digital Optical module (DOM)
a self-contained ”mini”-
DAQ
records timestamps digitizes stores transmits to surface at request
an optical sensor10 inch Hamamatsu R-7081
mu metal cage
PMT
penetrator HV board
flasher board
DOMmain board
pressure sphere
optical gel
delay board
Dark noise rate < 1 kHz SN monitoring within
our Galaxy
DOM Mainboard
fast ADC recording at 40 MHz over 5 s
event duration in ice
2xATWD
FPGA
Memories
HV Board Interface
CPLD FPGA (Excalibur/Altera) reads out the ATWD
handles communications time stamps
waveformssystem time stamp resolution 7 ns wrt
master clock
FPGA (Excalibur/Altera) reads out the ATWD
handles communications time stamps
waveformssystem time stamp resolution 7 ns wrt
master clock
oscillator (Corning Frequency Ctl) running at 20 MHz
maintains f/f < 2x10-10
2 four-channel ATWDsAnalog Transient Waveform
Digitizerslow-power ASICs
recording at 300 MHz over first 0.5s
signal complexity at the start of event
2 four-channel ATWDsAnalog Transient Waveform
Digitizerslow-power ASICs
recording at 300 MHz over first 0.5s
signal complexity at the start of event
Dead time < 1%
Dynamic range - 200 p.e./15 ns- 2000 p.e./5 s
energy measurement (TeV – PeV)
-time stamped w.f. recorded & analyzed
- downgoing muons detected
- photon timing accuracy in ice < 8 ns
- local clock calibration < 5 ns r.m.s.
- 15% of waveforms have > 1 p.e.
IceCube design works
IceCube physics performance simulations benefit from AMANDA experience
IceCube will be able to identify tracks from for E > 1011 eV cascades from e for E > 1013 eV for E > 1015 eV
Background mainly downgoing cosmic ray ’s(+ time coinc. ’s from uncorrelated air showers) exp. rate at trigger level ~1.7 kHzatm. rate at trigger level ~300/day
Rejected using direction/energy/flavor id temporal/spatial coincidence w. source
for E < 1PeV focus on the Northern sky
for E > 1PeV sensitive aperture increases w. energy full sky observations possible
Eµ=10 TeV
IceCube effective area and angular resolutionfor muons
Galactic center
E-2 spectrum
quality cuts and bkgr suppression (atm reduction by ~106)
further improvement expected
using waveform info
further improvement expected
using waveform info
Median angular reconstruction
uncertainty ~ 0.8
Diffuse flux / Point sourcesObjective (after removal of atm background): reject the steep energy spectrum of atm retain as much signal as possible from a (generic) E-2 spectrum
Use optimized energy cut E number of hit OM’s
Eµ=6 PeV, 1000 hitsEµ=10 TeV, 90 hits
Diffuse hard E cutE > 100 TeV
Point sources softer E cut
+ spatial correlation
Assume generic flux dN/dE = 10 –7 E-2 (cm-2s-1sr-1GeV)
Expect
~103 events/year after atm rejection
~75 events/year after energy cut
cf background 8 atm
atm v
signal
Sensitivity (1 y): 8.110-9 E-2
(cm-2s-1sr-1GeV)
blue: after atm rejectionred: after Ecut
Diffuse flux
Steady point sourcesSearch cone 1 opening half-angle+ ”soft” energy cut (< 1 TeV)
Transient point sources – eg GRB
Essentially background-free search energy, spatial and temporalcorrelation with independent observation
For ~1000 GRB’s observed/yearexpect (looking in Northern sky only) signal: 12 background (atm ): 0.1
Sensitivity GRB (1 y): ~0.2 WB
Excellent prospects for detection of GRB ’s within 1-2 years-> if models realistic
Sensitivity point sources (1 y):
5.510-9 E-2 (cm-2s-1GeV)
Cascadese e
Lcascade ~10 m small cf sensor spacing”spherical” energy deposition
at 1 PeV, Øcascade ~ 500 m
~10% in log(E/TeV)
E = 375 TeV
IceTop veto on cosmics
IceTop veto on cosmics
C.O.G. insidearray
C.O.G. insidearray
“double bang”
~300m for PeV
E << 1 PeV 2 cascades coincideE 1 PeV ”double bang”E >> 1 PeV ”lollipop” (partialcontainment, reconstruct track
+ 1 cascade)
sensitivity to all flavors4 coverage
For diff
use fl
ux expect sim
ilar s
ensitivity
in the ca
scade ch
annel as i
n the m
uon channel
Considera
ble impro
vement of o
verall s
ensitivity
Neutralino dark matterastro-ph/0401113 (Lundberg/Edsjö)WIMP orbits in the solar system
perturbedRates from the Earth affected Rates from the Sun less affected
Direct and indirect searches complementary Past/present history of solar syst. Low/high energy tail of vel. distr.
Disfa
vored
by direct search
Sun
Earth
AMANDA system IceCube
AMANDA IceCubePower consum. 2 MW 5MWTime to 2400 m 120-140 h 35-40 hFuel (gal/hole) 10000-12000 7000-8000 Set-up time 5 – 6 weeks 18-25 d
AMANDA IceCubePower consum. 2 MW 5MWTime to 2400 m 120-140 h 35-40 hFuel (gal/hole) 10000-12000 7000-8000 Set-up time 5 – 6 weeks 18-25 d
Goals
18 holes/season
2450 m deep
straight within 1m
quality logged
Goals
18 holes/season
2450 m deep
straight within 1m
quality logged
Enhanced Hot Water Drill
Hose-reel atSouth Pole (Jan 2004)
Hose-reel with hose,built at Physical Sciences Laboratory
UW-Madison (Nov 2003)
In-D oor deploym ent
DOM Hub
Cable Winch
Slip Ring
Deployment Room
Tower Operations Structure(TOS)
OMs
DAQ
Entire string can be operated as soon as the OMs are connected.
Can operate string during drop
Mounting, testing + drop of string with 60 OMs
expected to take ~ 20 hours
Mounting, testing + drop of string with 60 OMs
expected to take ~ 20 hours
Status of IceCube project many reviews – international and within the U.S. - strongly emphasize
the exciting science which can be performed with IceCube
in Jan 2004, the U.S. Congress approvedthe NSF budget including the full IceCube MRE
significant funding approved also in Belgium, Germany and Sweden
in Feb 2004, NSF conducted a baseline review “go ahead”
deployment over 6 yearsIceCube strings IceTop tanks4 8 Jan 200516 32 Jan 200632 64 Jan 200750 100 Jan 200868 136 Jan 200980 160 Jan 2010
AMANDA / IceCube integrationAmanda now runs with TWR data similar in structure to IceCube work on a s/w trigger
Position of 1st IceCube strings as close to Amanda as possible for verification & cross-calibration … but logistics and
safety requirements
1. 1st IceCube strings: Amanda as calibration device 2. IceCube ~ 20 strings + Amanda: powerful combined detector3. Full IceCube: Amanda included as a fully integrated,
low threshold subdetector
CONTINUOUS SCIENCE OUTPUT DURING CONSTRUCTIONCONTINUOUS SCIENCE OUTPUT DURING CONSTRUCTION
drill development on schedule for operation at Pole in Jan 2005
instrumentation production for the 4 string first season starts this summer
50% PMTs delivered – on schedule 3 DOM production sites
Wisconsin 290 1st season DESY 60 1st season Sweden 50 1st season
spheres ordered – 40K depleted Benthos (dark noise ~0.8 kHz) DOM mainboard – designed @ LBNL tests OK DAQ S/W developed data transfer DOM DOM Hub Data Collection prog tested implementation for first season’s DAQ cables – Ericsson, Sweden / JDR, Netherlands preparing for analysis of early data (calibration, testing)
4 DOM’s are collecting IceTop data using test s/w
Status of IceCube construction
View of DOMs
IceTop tank with hood at the South Pole – Nov 2003
IceTop Stations with DOMs – January 2004
Digitized muon signals from DOMs
Am
plit
ude
(AT
WD
cou
nts)
vs
tim
e (n
s)
power cable
signal, freeze control,
temperature controlcables
1st challenge – successful deployment
of strings 2004/2005
Summary
IceCube is for real ! - and moving ahead at full speedAMANDA experience provides for huge benefits
- both logistics-wise and for simulations/reconstruction
IceCube is expected to be considerably more sensitive than AMANDA provide new opportunities for discovery with IceTop – a unique tool for cosmic ray physics
first data for Neutrino 2006
data taking during construction first data augment AMANDA data later AMANDA an integral part of IceCube
USA (12)USA (12)
Europe (11)Europe (11)
VenezuelaVenezuela
JapanJapan
New ZealandNew Zealand
• Bartol Research Institute, Delaware, USA• Univ. of Alabama, USA• Pennsylvania State University, USA• UC Berkeley, USA• Clark-Atlanta University, USA• Univ. of Maryland, USA
• Bartol Research Institute, Delaware, USA• Univ. of Alabama, USA• Pennsylvania State University, USA• UC Berkeley, USA• Clark-Atlanta University, USA• Univ. of Maryland, USA
• IAS, Princeton, USA• University of Wisconsin-Madison, USA• University of Wisconsin-River Falls, USA• LBNL, Berkeley, USA• University of Kansas, USA• Southern University and A&M College, Baton Rouge, USA
• IAS, Princeton, USA• University of Wisconsin-Madison, USA• University of Wisconsin-River Falls, USA• LBNL, Berkeley, USA• University of Kansas, USA• Southern University and A&M College, Baton Rouge, USA
• Universite Libre de Bruxelles, Belgium• Vrije Universiteit Brussel, Belgium• Université de Mons-Hainaut, Belgium• Universität Mainz, Germany• DESY-Zeuthen, Germany
• Universite Libre de Bruxelles, Belgium• Vrije Universiteit Brussel, Belgium• Université de Mons-Hainaut, Belgium• Universität Mainz, Germany• DESY-Zeuthen, Germany
• Universität Wuppertal, Germany• Uppsala university, Sweden• Stockholm university, Sweden• Imperial College, London, UK• University of Oxford, UK• NIKHEF, Utrecht, Netherlands
• Universität Wuppertal, Germany• Uppsala university, Sweden• Stockholm university, Sweden• Imperial College, London, UK• University of Oxford, UK• NIKHEF, Utrecht, Netherlands
• Chiba university, Japan• University of Canterbury, Christchurch, NZ
• Chiba university, Japan• University of Canterbury, Christchurch, NZ
ANTARCTICA
• Universidad Simon Bolivar, Caracas, Venezuela
THE END
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