1

Cosmic Ray Composition in the Knee Region

H. Tanaka

GRAPES-3 Collaboration

2

Cosmic Rays

High Energy Particle from outside of the Earth 107~1020eV Power Low Spectrum 　 E

－ γ

Particle Type Electron, Proton ~ Iron

Origin SNR?

Energy Spectrum

TeV PeV EeV ZeV

3

Knee in Energy Spectrum

What is the cause of knee ?Limit of AccelerationLeakage from the Galaxy or others

1015eV

Measurement of nuclear composition and their energy spectrum could be one of the key to the solution.

H

Fe

?

H

Fe

4

Air Shower Experiments

Tibet ASγ

KASCADEGRAPES-3

GRAPES-3 KASCADE Tibet ASObs. Height 2200m 100m 4300m

Density of Particle Detector

1det / 55m2

1.8%1det / 167m2

1.3%1det / 56m2

0.9%

Other Observations

560m2 Muon Det. 800m2 Muon Array300m2 Hadron Det.

128m2 MTT etc.

80m2 Burst Det.

Features Larger StatisticsLower E Threshold

Larger Statistics Lower E Threshold

GRAPES-3 has both of dens array and large muon detector at the high altitude.

5

SC MU

GRAPES-3 Experiment Location: Tamil nadu, Ooty 2,200m (800g/cm2)

Charged Particle (electron) Detector: Plastic Scintillator 1m2, 5cm thick x400 (8m separations)

Muon Detector:16 detectors (>1GeV) total 560m2

Observation:The number of electrons and the number of muons

6

Shower SizeSize Spectrum

Energy? Composition? MC, muon

LOG

LO G

N2.

5 dI/

dN [m

-2sr

-1s-1

N1

.5]

7

1

2

3

4

5

6

3 4 5 6 7 8LOG10(Ne)

LOG10(N

μ)

H　1014eV

H　1015eV

H　1016eV

Fe　1014eV

Fe　1015eV

Fe　1016eV

Energy

Nuclear　Number

γ　1014eV

γ　1015eV

γ　1016eV

Particle Type and Energy Estimated from Observations (MC)

Estimation of primary energy and nuclear mass number from the numbers of electrons and muonsModel dependency for HE-Hadronic interaction

Air Shower Simulation

Hadronic Interaction Model

* SYBILL 2.1* QGSJET01

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N- Ne diagram (M.C.)

M.C. simulation CORSIKA QGSJET01, SIBYLL2.1,

QGSJET-II

５ nucleousProton, He, N, Al,FeObservation

<n

um

ber

of

dete

cte

d

mu

on

s>

9

Multiplicity DistributionAl / Fe is fixed to 0.8

Ne: 105.0 - 105.2

marker Proton 0.3 He 0.4 N 0.3 Al 0.02 Fe 0.03 ObservationGood sensitivity of

cosmic ray mass

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Energy Spectra Analysis

1

10

100

1000

4 5 6 7Log10(Ne)

dI/dNexNe2.5

ALLHHeNAlFe

MC

Log10(Ne ）

Log1

0(E

/TeV

)

QGSJET

Log(E)

dI/

dE・E

2.5

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All-particle Spectrum

12

Proton Spectrum

Comparing with direct measurements is possible

13

Other Spectra

He N

Al Fe

14

Mean Mass Number

Lower threshold enables data to compare with direct measurements.

H

Fe

He

N

Al

15

SummaryGRAPES-3 can get energy spectra of five groups utilizing muon multiplicity distribution.

Change in proton spectrum and increase in mean mass with energy observed

The results with SIBYLL and QGSJET-II agree with direct and KASCADE measurements.

Extend spectrum to higher energy

16

THANK YOU

17

18

Air Shower Experiments

Tibet ASγ

BASJE

KASCADE

GRAPES-3 SPASE-2

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Method of EAS Observation

BASJE Bolivia (550g/cm2)

46 SDs (1 or 0.83 m2 each)

12 SDs (4 m2 each)

SPASE-2 South Pole (695g/cm2)

30 SDs (0.8m2 each)

KASCADEKarlsruhe (1020g/cm2)

252 SDsCentral DetectorMuon Tracking Detector

Tibet AsγTibet (606g/cm2)

500 SDs (0.5m2 each)

Emulsion chamber Burst detector

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Method of EAS ObservationLocation EAS Array

GRAPES-3 Ooty

800g/cm2

400 SDs

(1m2)

BASJE Chacaltaya

550g/cm2

46SDs(1m2)

12SDs(3m2)

SPASE-2 South Pole

695/cm2

30 SDs

(0.8m2)

KASCADE Karlsruhe

1020g/cm2

252 SDs

(3.2m2)

Tibet ASγ Yangbajing

606g/cm2

789 SDs

(0.5m2)

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Low Flux of Cosmic Ray around Knee

Low Flux 1 particle in 1m2 in a year

(>1015eV) Poor statistics in Direct

Method Air Shower Observation

above 1015eV

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Important Matters in Observing Cosmic Ray around Knee

To get enough statistics (Lower flux for higher cosmic rays)

1 particle in 1m2 in a year Air Shower Observation above 1015eV

Sensitivity of Cosmic Ray Mass The number of Muon

Large Area Muon detector

Solve the Uncertainty of Monte Carlo (high energy phenomena)

Compare the observation with direct measurements Density Shower Array for lower threshold energy

GRAPES-3 Experiment

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The First Report of Knee

“On the Size Spectrum of Extensive Air Showers”

G.V. Kulikov and G.B. KhristiansenJournal of Experiment and Theoretical Physics, 1958Break of size spectrum was reported between 106 – 107.

The cause of knee is not yet clear for 50 years.

How are Recent Observations?

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Energy Spectrum

25

Air Shower Observation

Primary particle

Observation

Muon Detector Particle Detector Array

, e

Low Energy Particle60GeV

High Energy Particle>1013eV

ATMOSPHERE

GROUND

MC

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Direct Measurements

JACEE Japanese American

Cooperative Emulsion Experiment

Balloon Experiment 1 - 1000 TeV The Antarctic

Emulsion Chamber X-ray film Lead Plate

RUNJOB RUssia Nippon JOint

Balloon experiment Balloon Experiment

10 - 1000 TeV Kamchatka to Moskva

JACEE

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Mean Mass Number

Much difference among them!

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Important Matters in Observing Cosmic Ray around Knee

To get enough statistics (Lower flux for higher cosmic rays)

Sensitivity of Cosmic Ray Mass

Solve the Uncertainty of Monte Carlo (high energy phenomena)

29

サイズ推定（横方向フィット）

x = -11.8m y = 27.3m s = 0.91

シャワーサイズ1.82×105

コアからの距離 (m)

検出

粒子

数検

出粒

子数

LOG

5.40.2

1

s

m

s

m r

r

r

rr

NKG 関数

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ミューオントラック検出装置検出装置 1 層 58 本の比例計数

管 (6m×10cm×10cm) 交互に組まれた 4 層で

　トラックを識別 合計 16 台 (560m2) E>1GeV

4 layers

58 counters6m

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EAS DataObservation 2000 – 2001 (560days) Shower Number 6×108

Shower Rate 13Hz

Shower Selection Core Location (>80m) Zenithal Angle θ < 25o

Monte Carlo Simulation CORSIKA

QGSJET-II (CORSIKA6.50)

SIBYLL 2.1 (CORSIKA6.50)

QGSJET01 (CORSIKA6.02)

Primaries Proton, He, N, Al and Fe

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Expanded GRAPES Collaboration(1) TIFR, Mumbai: H.M. Antia, S.K. Gupta, P.K. Manoharan, P.K. Mohanty,

P.K. Nayak, H. Tanaka, S.C. Tonwar

(2) Osaka City University, Japan: S. Kawakami, Y. Hayashi, S. Ogio, A. Oshima

(3) Aligarh Muslim University, Aligarh: Shakeel Ahmad, Badruddin, R. Hasan

(4) APS University, Rewa: A.P. Mishra, P.K. Shrivastava

(5) BARC, Mumbai: R. Koul, G.N. Shah

(6) J.C. Bose Institute, Kolkata: S. Ghosh, P. Joarder, S. Raha, S. Saha

(7) Gauhati University: R. Baishya, A.G. Baruah, K. Boruah, P.K. Boruah, P. Datta,

J. Saikia

(8) IIA Bangalore: D. Banerjee, P. Subramanian

(9) North Bengal University: A. Bhadra

(10) R.D. University, Jabalpur: R. Agarwal, S.K. Dubey, Santosh Kumar

ENDThanks for your kind attention!

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The Number of Electron and Muon

34

Target for present experiment getting the size spectrum and muon multiplicity

distribution Using M.C., energy spectrum of nucleus can

be deduced from these results

To achieve this, compact array (high density SD) and muon detectors with large area are required.

In this experiment our energy range is overlapping with direct measurement (Balloon exp.). It means we have an anchor point, even though our results are totally M.C. dependent.

35

Location of GRAPES-3 Ooty Air Shower Experiment

•Location　Mt.　Ooty,　South　India 　E　76.7°　N　11.4°2,230m　a.s.l.　(800g/cm2)

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Future Expansion Plansto observe higher energy cosmic rays

Radio Telescope(326MHz)

Shower Array

1km2 Array

Muon Detector

New Muon Detector

Radio Array (30-70MHz)

100m2 Hadron Calorimeter

Neutron Monitor

37

空気シャワーシミュレーションCORSIKA

ハドロン相互作用モデル DPMJET

GRT + minijet HDPM

現象論的モデル neXus

GRT + minijet QGSJET

GRT + minijet 空気シャワー向け

SIBYLL minijet 空気シャワー向け

VENUS GRT （ Gribov-Regge Theor

y ）

110m　a.s.l.2-D　Half　maximum

D.Heck　et　al.,　Proc.　ICRC27,　233,　2001　

電子数

ミュ

ーオ

ン数

38

ハドロンモデルの影響

1 PeV 鉄

電子数 ミューオン数

両者とも　 ~ １０％　程度の違い

39

OBS

QGSJET Proton

SIBYLL Fe

QGSJET Fe

SIBYLL Proton

ハドロンモデル依存性

CORSIKA QGSJET SIBYLL

Log( サイズ）

<検

出ミ

ュー

オン

数>

40

Knee のモデル

1. 超新星残骸での加速2. 超新星衝撃による加速3. 斜め衝撃波による加速4. 多様な超新星による加速5. 単一の超新星残骸での加速6. 銀河風での再加速7. 火の玉モデル

8. 銀河からの漏れ出し9. 銀河からの異常拡散10. 銀河磁場中の拡散と漂流11. 乱流銀河磁場中の移流拡散12. 拡散漂流モデル

13. 光分裂と拡散14. ニュートリノとの相互作用

加速 伝播

相互作用

41

Shower Cascade in the AtmosphereAir Shower Phenomena

Nuclear Cascade p, n, , 0, K, K0, …

[decay] 0 + [8×10-17sec]

+ () [3×10-8sec] High Energy: COLLISION Low Energy: DECAY

Electromagnetic Cascade Pair Creation e+ + e-

Bremsstrahlung ee +

Primary particle

Observation

air

42

個々の成分の比較

個々の成分で比較できる！

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シャワー到来方向

検出器へ粒子の入射する時間差から到来方向を推定するガンマ線点源の観測時の際は重要

44

シャワー到来方向推定時

間差

(ns

ec)

（ｍ）

EAS DataObservation 2000 – 2001 (560days) Shower Number 6×108

Shower Rate 13Hz

Shower Selection Core Location (>80m) Zenithal Angle θ < 25o

Monte Carlo Simulation CORSIKA

QGSJET-II (CORSIKA6.50)

SIBYLL 2.1 (CORSIKA6.50)

QGSJET01 (CORSIKA6.02)

Primaries Proton, He, N, Al and Fe

The Number of Electron and Muon