Cosmic Rays in IceCube Patrick Berghaus University of Delaware - - PowerPoint PPT Presentation

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Cosmic Rays in IceCube Patrick Berghaus University of Delaware IceCube Components IceTop Surface Array: Surface: 1km 2 area 2835 m a.s.l LE electromagnetic -1450 m InIce Volume Detector: 1km 3 volume -2450 m HE muons -2620 m Patrick

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Cosmic Rays in IceCube

Patrick Berghaus University of Delaware

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Patrick Berghaus Cosmic Rays in IceCube

IceCube Components

Surface: 2835 m a.s.l

1450 m
2450 m
2620 m

IceTop Surface Array: 1km2 area LE electromagnetic InIce Volume Detector: 1km3 volume HE muons

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Patrick Berghaus Cosmic Rays in IceCube 3

Electromagnetic Particles (10s-100s of MeV) LE Muons (1-10 GeV) HE Muons (TeV) Shower Axis

IceTop Surface Array InIce

Primary Energy: 1-100s PeV InIce Muon Multiplicity: 10s-1000s

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Patrick Berghaus Cosmic Rays in IceCube 4

CR Energy range of IceCube/IceTop

IceCube CR events IceTop Coincident Knee Second Knee? Ankle

Main Science Goals: Primary composition change around Knee Transition to Extragalactic CR at “Second Knee”?

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Patrick Berghaus Cosmic Rays in IceCube 5

IceTop Deployment

Freezing Unit 2 Tanks per Station Temporary Cover

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IceTop Station

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65cm Snow Height 93cm 130cm DOM DOM water perlite snow

x2 x78

IceTop Tank

view from above, unfrozen

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Patrick Berghaus Cosmic Rays in IceCube 8

Oldest (2005/06) Newest (2009/10) a.u.

Effect of Snow Coverage

(Reconstructed Shower Core Position)

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IceTop Calibration Procedure

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Muon Peak /EM Bkg

Tank Calibration

Source: T. Waldenmaier, DESY-Zeuthen

Snow reduces EM signal, muons unaffected

Snow Height

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Zenith Angle Shower Core Position

Snow Effects in Detector Simulation

Here: Parametrization of detector response in dependence of particle type and snow height Soon: Full GEANT-4 simulation Red: Default Response Parametrization Blue: Snow Attenuation and individual Snow Height for each tank

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Patrick Berghaus Cosmic Rays in IceCube 12 arXiv: 0711.0353

IceTop Shower Reconstruction

“Double-Logarithmic Parabola”: MC-derived empirical description (slope) (amplitude)

Eprim = f(S125, θzen)

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IceTop Event

All IceTop Waveforms

Estimated Energy: 183 PeV Zenith Angle: 50° color: time size: signal Reconstruction

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Raw IceTop-only CR Spectrum

Below Knee (E-2.7) Above Knee (E-3)

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InIce Muon Flux (IC22, 2008)

arXiv:0902.0021

Neutrinos Muons 99.999% of events (directly) from CR

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Patrick Berghaus Cosmic Rays in IceCube 16 astro-ph:0803.2943

IC22 (1month), PRELIMINARY!

Muon Spectrum

Derived from muon tracks near the horizon Higher angles: High-multiplicity muon bundles dominate over single HE muons

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minimum ionizing (muons in large air showers) proportional losses (high-E muons)

few TeV continuous stochastic

hep-ph/0407075

Muon Energy Losses in Matter (Ice)

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Size: PMT Signal Color: Time

High-Energy Muon

Catastrophic E-loss (Bremsstrahlung) >50 TeV

Small signal from continuous E-losses Identify stochastic losses to distinguish HE muons from high-multiplicity muon bundles

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Patrick Berghaus Cosmic Rays in IceCube 19

Source: T. Gaisser

ν µ

At 60°, light meson decay dominates up to ≈500TeV

Prompt Leptons from Charm Decay

Charm represents major systematic uncertainty for neutrinos above 100 TeV For vertical muons, prompt component becomes dominant at ≈200 TeV

Light mesons: Flux α 1/cosθzen Prompt: constant angular Flux

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Shower Axis

IceTop Reco: ∆log10E≃0.1 (prim) ∆θ≃1◦ ∆r≃20 m InIce Reco: ∆log10E≃0.3 (µ) ∆θ≃0.7◦ ∆r≃30 m Reconstructions are completely Independent Relation between energies depends On CR primary type

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Size: PMT Signal Color: Time

Shower core fully contained in IceTop array High-Multiplicity HE Muon Bundle In InIce/DeepCore

IceTop/InIce Coincident Event

Muon energy estimated from sum of DOM signals

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400 ns

500 pe

High-pt muons Shower Core Scattered Photons

DOM Waveforms

DOM readout triggered by outlying muons: Characteristic for large CR bundles

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IceTop/InIce Energy Correlation

<QMC(A)> = <Qdata> <log A> = He at Eprim ≈ 10PeV

PRELIMINARY

IceTop (EM) InIce (HE muons)

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S. Tilav et al., arXiv:1001.0776

Atmospheric Temperature IceTop (barometric) InIce (temperature) Teff: Temperature weighted by muon production probability

≈20%

Seasonal Variations

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First Extraterrestrial IceCube Signal

13 Dec. 2006: Solar Flare seen in IceTop Count Rate

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