Cosmic Ray Physics with the IceCube Observatory

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 1

Hermann KolanoskiHermann Kolanoski

Humboldt-UniversitHumboldt-Universitäät zu Berlin and t zu Berlin and DESYDESY

for the IceCube Collaborationfor the IceCube Collaboration

Cosmic Ray Physics Cosmic Ray Physics with the with the

IceCube ObservatoryIceCube Observatory

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 2

IceCube DetectorDetector Completion Dec 2010

IceCube with IceTop is a 3-dim Air Shower Detector

unprecedented volume

CR Analyses

•air showers in IceTop

•muon (bundle)s in IceCube

•atm. neutrinos in IceCube

•IceCube - IceTop coinc.

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 3

Energy range of IceCube/IceTop< PeV > EeV

Anchor to direct measurement of

composition ~300 TeV

Look for transition to extra-galactic <

EeV

(IceTop EAS)

(in-ice µ,ν)

Outline

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 4

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 5

Final IceTop Detector Array 2011

final detector:81 stations (162 tanks)

mostly ~ 125 m; In-fill array: 3 inserts +5 closest stations

In-fill

~125 m

Calibration: Vertical Equivalent Muons

1 VEM ≈ 125 PE

signal distribution in untriggered

calibration runs

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 6

IceTop Signal Recording

charge [PE]

volta

ge

time [ns]

leading edge

baseline

3.3 ns; 128 bins 420 ns

DOMs

snow height on tanksmuon signal

e.m. background

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 7

Trigger and Data SelectionSingle DOM above threshold (~0.2 VEM):

digitization of waveform (3.3 ns bins)

Local Coincidence (‘HLC hits’): both tanks above threshold

readout of full waveform to IceCube Lab

Soft Local Coincidence (‘SLC hits’):all DOMs above threshold send a timestamp and integrated charge

catch single muons

Single tank trigger for calibration with single muons

Reconstruction: standard ( 3 stations) 0.3 PeVinfill extension: 100 TeV

Select extended air showers:

Shower Size Spectrum with IT73

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 8

IT73 (90% of final) cos𝛉 > 0.8 A = 52×104 m2 >3 stations

10

100

1000events per bin

per year

(log10S125 = 0.05)

IT73 data(preliminary)

IT73 simulation

Work in progress

Effective Area

IceTop only

IC-IT coinc.

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube

IT73/IC79 configuration, >3 stations , cos𝛉>=0.8, A=0.52 km2

9

Cosmic Ray Spectrum

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 10

IceTop IT73 only:>5 stations cos𝛉>=0.8, A=52.1×104 m2

‘flattening’, also observed in IT26,

Kascade-G.

work on systematics in progress

CR Spectrum with IT26

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 11

preliminary

arXiv 1202.3039, submitted to ApP

CR Spectrum: Comparison with other Experiments

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 12

Cosmic Rays: spectrum and composition

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 13

IceCubes

ho

we

r a

xis

HE MuonsTeV’s

electro-mag. particles: MeV’s

LE MuonsGeV’sIceTop

IceCube/IceTop's Strength

EM

IN-ICE COMPOSITION SENSITIVE VARIABLES I

S125: shower size at the surface

K70: size of muon bundle in-ice

IceTopIn

-ice

Pure Iron

Pure proton

Neural Networkoutput

IC/IT40 Composition Analysis

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 14

FIRST ATTEMPT FOR COMPOSITION (IC40)

Preliminary

Preliminary

Preliminary

IC/IT40 Composition Analysis: Results

~ 1month of IC40 subarray (with little snow)

energy from 1 to 30 PeV (only)

systematics dominated

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 15

major progressexpected for the next

analyseswith larger detector

Submitted to Astrop. Phys.

separation power(expected to improve)

IN-ICE COMPOSITION SENSITIVE VARIABLES II

IT73/IC79 Composition Analysis

16

In-ic

e

IceTop

Muon stochastic loss

Avg. muon energy loss

for same deposited energy:

more stochastic loss

more HE muons lighter elements

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube

Exploit additional mass sensitive observables

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 17

Supporting Composition Measurements

1 VEM charge enhanced if

signalem signalmuon

Muon counting in air shower dataZenith angle dependence of shower size

Proton assumption

Iron assumption

IT26 spectrum analysis 1-100 PeV- arXiv:1202.3039

preliminary

preliminary

Surface muon content

simulation

PeV Gamma with InIce Veto against muons

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 18

HI column densities

IceTop shower with no activity in IceCube

upper limit E = 1.2 – 6.0 PeV (90% c.l.)

--- sensitivity E = 1 – 10 PeV (90% c.l.)

• sensitivity for E = 1 PeV (90% c.l.)

preliminary

PeV Gamma: Point source sensitivity

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 19

TeV-sources extrapolatedto 1PeV without cut-off

IceCube 5 year sensitivity to point sources

lowest declination reached by the Galactic plane

preliminary

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 20

Low energy transient rate variations from Sun, SN, GRB, ...

Since than: IceTop increased spectral sensitivity taking differential rates at multiple thresholds

[ApJ Lett 689 (2008) L65]Sun flare observation Dec 13, 2006:

rate increase at 2 different thresholds

Galactic CR Spectrum

• GOES spacecraft

GRB sensitivity: Large events but unmonitored part of the sky

GeV 10 ,200 ,cm erg10 oo25 EF

May 17, 2012 – GLE 71

H.Kolanoski - Cosmic Ray Physics with IceCube 21

MPE

SPE1

SPE2SPE3

IceTop Rates plotted here are averages of the four groups

shown above.

• ~1% enhancement in SPE1 & SPE2• Tiny enhancements in SPE3/MPE• Unusual slow decay or second phase

ECRS, July 3-8, 2012

Observations

preliminary

Cosmic rays in IceCube (deep ice)

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 22

High Energy Muons in the Deep Ice

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 23

muon bundlesingle HE muon

Nµ~A0.23 E0.77

Muon Multiplicity

Q3.

5 d

N/d

Q

Q ~ Nµ

Test composition models

10 TeV 10 EeV

enlarged energy range witout coincidence

Spectra from Muon Bundles

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 24

preliminary

preliminary

preliminary

room for prompt muons from charm?

Comparison to Poly-Gonato Model

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 25

Poly-Gonato (+G-H3a extra-galactic)

E1

.7-w

eig

hte

d

total (polygonato + extragal.)no efficiency correction included

heavier than iron(extrapolated from

low energies)

extragalactic

room for prompt muons?

Atmospheric

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 26

at high energies remaining background

for comic neutrinos

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 27

Cosmic Rays: High-pT muonsHigh-pT muons modeled by QCD simulation (π, K, c, …)

O(10 m)

> 135 m

bundle

LS muon

power law

exponential

pQCD

preliminary

preliminary

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 28

High-pT Muons: Zenith Angle Distribution

DPMJET

QGSJET

MC=data

strong disagreementfor QGSJET & Sybill

π

K

c

Zenith angle dependences:

• π, K interaction vs. decay competition

• prompt: no dependence larger K/π ratio and/or more prompt?

d > 135 m

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 29

Cosmic Ray Anisotropy Large Scale ─ Compared to Northern Sky

the orientation of the dipole momentdoes not correspond to the relative motion

in the Galaxy (Compton-Getting effect)

diffusive transport from nearby sources?observed small scale (10°) structures few pc distance

in-ice only

Cosmic Ray Anisotropy

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 30

IceCube

IceTop

• CR Rate ~ 10 Hz in IT81 (E > 100 TeV)

• ~3 x 108 events / year

• Sensitive to > 10-4 anisotropy

• CR Rate ~ 2 kHz in IC86 (E > 10 TeV)

• ~6 x 1010 CR events / year

• Sensitive to > 10-5 anisotropy

Measurements with IceCube and IceTop

Air showers in IceTop :

in principle much betterenergy resolution, binning limited by statistics

potential of including composition sensitivity

Muons in IceCube:

lower energy; larger zenith range;higher sensitivitiessmall scale structures

IC59 - 400 TeV

IC59 - 20 TeV

IT73 - High energy (~2 PeV), preliminary

Energy Dependence of CR Anisotropy

31

• Anisotropy changes in position, size

• Above 400 TeV there’s indication of an increase in strength.ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube

preliminary (IT73)

Summary

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 32

• Cosmic Ray energy spectrum (‚flattening‘ at ~ 23 PeV)

• CR composition (first coinc. results, different methods model test), PeV γ rays

• connecting direct measurements with dominantly extra-galactic CR

• physics of airshowers: high-pT muons, composition, K/π, charm, …

• transient events: heliospheric physics, GRB, …

• CR anisotropy in PeV range, likely increase with energy

IceCube/IceTop is a unique 3-dim Air Shower Detector

Results:

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 33

Backup Slides

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 34

35

ENERGY RESOLUTION

SNOW CORRECTIONS

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 36

Feb. 2012

cos

0 z

meas eSS

Snow corrected(in shower reco)

Events selected bycore location

CR Spectrum: Comparison with IT26 and IT40

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 37

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 38

Strategies of Composition Analyses

proton

N

X / g cm-2

earlier

e/m

μ

first interaction

observationN

X / g cm-2

e/m

μearlier

more

heaviernucleus

• IceTop & InIce

IceTop EM vs InIce MUON

• IceTop

- zenith angle of e.m. - curv. of shower front

- GeV-muons in IceTop:

• IceTop & Radio

(future?)- shower max. Xmax

Complementary methods

reduce model dependency~ 680 g cm-2

Big Coincident Event

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 39

CR Spectrum: Comparison with other Experiments

ECRS, July 3-8, 2012 H.Kolanoski - Cosmic Ray Physics with IceCube 40