The Status of IceCube Mark Krasberg University of Wisconsin-Madison RICH 2004 Conference, Playa del...
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Transcript of The Status of IceCube Mark Krasberg University of Wisconsin-Madison RICH 2004 Conference, Playa del...
The Status of IceCubeMark Krasberg
University of Wisconsin-Madison
RICH 2004 Conference, Playa del Carmen, Mexico
Dec 3, 2004
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IceCube – a next generation observatory a cubic kilometer 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 of photoelectrons • entire waveform read out
Expected performance wrt AMANDA• increased effective area/volume• superior angular resolution • superior energy resolution
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PMT noise: ~1 kHzOptical Module
“Up-going”(from Northern sky)
“Down-going”(from Southern sky)
AMANDA-II19 strings677 OMs
Trigger rate: 80 HzData years: >=2000
PMT looking downward
Measurements:►in-situ light sources►atmospheric muons
Average optical ice parameters:λabs ~ 110 m @ 400 nm
λsca_eff ~ 20 m @ 400 nm
bubbles
dust
A
dust
ice
Scattering Absorption
Polar Ice Optical Properties
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IceCube Science Goals
• High energy neutrinos from transient sources (GRBs and Supernovae)
• Steady and variable sources of high energy neutrinos (AGNs and SNRs)
• Sources of high energy cosmic rays• WIMPs (Dark Matter)• Unexpected or exotic phenomena• Cosmic Ray Physics
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IceCube ConceptDeep In-Ice Array 80 strings / 60 DOMs each 17 m DOM 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 of Antarctic ice for UV – blue Cherenkov light
Ice Top Surface Array 2 frozen-water tanks (2 DOM’s each) above every string
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Amundsen-Scott South Pole Research Station
8 + N + N + + XX
CC muon neutrino muon neutrinointeractioninteraction
tracktrack
AMANDA
muon
event
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Track Reconstruction in Low Noise Environment
• Typical event: 30 - 100 PMT fired• Track length: 0.5 - 1.5 km• Flight time: ≈4 µsecs • Accidental noise pulses:
10 p.e. / 5000 PMT / 4 µsec AMANDA
IceCube
IceTop
1200 m
Energy ReconstructionSmall detectors: Muon energy is difficult to measure because of fluctuations in dE/dx IceCube: Integration over large sampling + scattering of light reduces the energy loss fluctuations.
Eµ=6 PeV, 1000 hitsEµ=10 TeV, 90 hits
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1 PeV (300m)
decays
- flavors and energy ranges
e
Log(energy/eV)12 18156 219
e
• Filled area: particle id, direction, energy• Shaded area: no particle id
pulse
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IceCube effective area and angular resolutionfor muons
Galactic center
E-2 spectrum
quality cuts and background suppression (atm reduction by ~106)
further improvement expected
using waveform info
Median angular reconstruction
uncertainty ~ 0.8
MacroBaikalAmanda
Diffuse Fluxes - Predictions and Limits
IceCubeSensitivity after 3 years
Point sources: event rates
Atmospheric
NeutrinosAGN* (E-2)
Sensitivity(E-2/(cm2 sec GeV))
All sky/year
(after quality cuts)100,000 -
Search bin/year 20 2300 -
3 year: Nch > 40
(E > 7 TeV)0.82 1370 2.4 x 10-9
Flux equal to 3x current AMANDA limit
dN/dE = 10-6*E-2/(cm2 sec GeV)
Compared to AMANDA-II:7 times more PMT
--> 50 to 100 times more atmosph. neutrinos@ better angular and energy resolution
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IceCube Digital Optical Module
Digital Optical Module • records timestamps
• digitizes waveforms
• transmits to surface at
request via digital
communications
•can do local coincidence
triggering
optical sensor10 inch Hamamatsu R-7081
mu metal cage
PMT
penetrator HV board
flasher board
DOMmain board
pressure sphere
optical gel
delay board • design requirement
Noise rate ~1 kHz• SN monitoring within
our Galaxy
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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)
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DOM Waveform Capture
t
• Altera Excalibur ARM922t P+ 400k gate FPGA on a single chip
• CPU runs data acquisition, testing facility, and diagnostic utilities
• FPGA controls communications interface, time critical control of DAQ hardware, fast feature extraction of waveforms
• 2× ATWD – each with 4 channels capable of digitizing 128 samples at rates from 0.25 – 1.0 GHz. 2 of them for ‘ping-pong’ mode.
• 3 gain channels in ATWD for complete coverage of PMT linear region
• 10-bit, 40 MHz FADC for capture of extended photon showers in the ice (6 s wide).
High Gain
Medium Gain
Low Gain
400 ns window
Calibration
1. Calibration of sensors in the lab at temperatures between -20 and -55C (deep ice: -18C to -42C)
2. LED Flashers on each module, 12 LEDs, in 6 directions and 2 angles (10^10 photons)
3. Special “high energy” lasers
4. Timing calibration is feature of DOM: 5 nsec
5. IceTop: High level cross calibration of muon tracks with air showers.
6. Shadow of the Moon (at 25 to 30 degree elevation): Muon rate of about 1500 Hz will allow to calibrate angular resolution in astrophysical coordinates in short time scales.
21
DOM Testing
DFL (Dark Freezer Lab) is large, dark, cold container which holds N test stations (N is site-dependent) each of which schematically looks like the figure.
Optical fiber system carries light from optics breadboard (diode laser, LED pulser, monochromator-tuned lamp) to each DOM.
Optics spreads light evenly out across PMT photocathode.
22
Dark Freezer laboratory: Test all optical sensors for ~2 weeksat temperatures -55°C to +20°C
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24
PMT HV Calibration
C
O
U
N
T
S
CHARGE
VOLTAGE
G
A
I
N
Nominal HV Setting
25
Final Acceptance Test Results
Detection of Synchrotron across the street
• In-Ice Noise Rate ~ 1 kHz
• Time Resolution < 3ns
• Noise Stability Monitor detected
Synchrotron radiation from the SRC,
Physical Sciences Lab, Wisconsin
26
Triggering on Cosmic Rays
Single PE trigger Local Coincidence triggering for DOMs with 1.5m vertical separation
27
A six hour flight from New Zealand to McMurdo Station, via C-141 “Starlifter”A six hour flight from New Zealand to McMurdo Station, via C-141 “Starlifter”
Getting to the South PoleGetting to the South Pole
28A three hour flight from McMurdo to South Pole Station, via C-130 “Hercules”A three hour flight from McMurdo to South Pole Station, via C-130 “Hercules”
29Hose-reel at
South Pole (Jan 2004)
Hose-reel with hose,built at Physical Sciences Laboratory
UW-Madison (Nov 2003)
30
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SummaryIceCube is deploying 256 DOMs next month!
IceCube is expected to be • considerably more sensitive than AMANDA • provide new opportunities for discovery• with IceTop – a unique tool for cosmic ray physics
• Data taking begins early next year
IceCube strings IceTop tanks4 8 Jan 200516 32 Jan 200632 64 Jan 200750 100 Jan 200868 136 Jan 200980 160 Jan 2010
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IceCube drill camp construction site of the first hole,
Nov 25, 2004
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USA (12)USA (12)
Europe (12)Europe (12)
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• Universität Dortmund, Germany
• Universite Libre de Bruxelles, Belgium• Vrije Universiteit Brussel, Belgium• Université de Mons-Hainaut, Belgium• Universität Mainz, Germany• DESY-Zeuthen, Germany• Universität Dortmund, Germany
• Universität Wuppertal, Germany• Uppsala university, Sweden• Stockholm university, Sweden• Imperial College, London, UK• Oxford university, UK• Utrecht,university, Netherlands
• Universität Wuppertal, Germany• Uppsala university, Sweden• Stockholm university, Sweden• Imperial College, London, UK• Oxford university, UK• Utrecht,university, Netherlands
• Chiba university, Japan• University of Canterbury, Christchurch, NZ
• Chiba university, Japan• University of Canterbury, Christchurch, NZ
ANTARCTICA
• Universidad Simon Bolivar, Caracas, Venezuela