チャカルタヤ山における空気シャワー実験

本田　建　 (山梨大学 )

Knee 領域の Energy Spectrum

K.Honda1,N.Ohmori3,K.Shinozaki4,N.Inoue4,M.Tamada5,N.Kawasumi2,N.Ochi,

K.Hashimoto2,I.Tsushima2,A.Ohsawa6,H.Aoki7,K.Yokoi8,T.Matano9,

N.Martinic10,R.Ticona10,C.Aguirre10

[1]Faculty of Engineering, Yamanashi University, Kofu, 400-8511, Japan[2]Faculty of Education, Yamanashi University, Kofu,400-8510, Japan[3]Faculty of Science, Kochi University, 780-8520, Japan[4]Faculty of Science, Saitama University, 388-8570, Japan[5]Faculty of Science and Technology, Kinki University, 577-8520, Japan[6]Institute for Cosmic Ray Research, University Tokyo, 277-8582, Japan[7]Faculty of Science, Souka University, 192-8577, Japan[8]College of science and Engineering, Aoyama Gakuin University, 157-8572, Japan[9]Shibakubo-cho 3-28-10,Tanashi,188-0014 Japan[10]Institute de Investigaciones Fisicas Universidad Mayor de San Andres, Bolivia

Collaborator

Air Shower Array at Mt. Chacaltaya (The hybrid experiment with AS and EC)

• 5200 m a.s.l ( 540 g/cm2)

• Scintillation detector

for density

0.25 m2 36 　　●　　 1.0 m2 9 　■□

for Fast Timing

0.25 m2 8 　 ○ 1.0 m2 5 □

Density det. (0.25m2)

Density det. (1.0m2)

FT det. (0.25m2)

FT det. (1.0m2)

20m

X

Y

dJ/dE = dJ/dNest × dNest/dE

The resolution of size (Array design)

The effect of detector

(thickness of scintillator) Analysis method

(analysis program)

Experimental Condition

Interaction Model Chemical composition

Physics

Energy Spectrum Nobs spectrumNest spectrum

dJ/dNest = dNest/dNobs dJ/dNobs

Simulation

CORSIKA ＋ QGSJET 　 modelPrimary composition

(1) proton only ～ above 2×104 GeV

(2) iron only ～ above 5×104 GeV

Include the detector response for each detector (plastic scintillator with 5cm thickness)

Simulated EAS data were re-analyzed to get the Shower Size(Ne) with our analysis method

Ｓｉｍｕｌａｔｉｏｎ

dNest/dE　　　　　　　 dNest/dNobs 　

E

Nest

Nest

Nobs

data reduction

• data analysis に Soft trigger を使用。 trigger detector に 1 particle 以上 （ trig=1) trigger detector に 2 particle 以上 （ trig=2) ………• Simulation data も同様に Soft trigger を使用して analysi

s した。　　 Soft trigger 別の dNest/dNobsを求め、それぞれについて

Detection Efficiency を求めた。• 各Ｔｒｉｇによる Energy spectrum を求める。

Observation data Nobs spectrum trig=1

R<10m

Θ＜ 30°

2.692.5x106

3.0

Observation data Nobs spectrum trig=2

2.71 4.4x106

2.97 R<10m

Θ＜ 30°

Observation data Nobs spectrum trig=3

2.74

2.98

9.0x106

R<10m

Θ＜ 30°

Simulation data Nest spectrum trig=2

Energy Spectrumtrig=2 trig=3

Energy Spectrum

2.5

3.0

3.5

4.0

4.5

5 6 7 8

Chacaltaya proton-onlyChacaltaya proton-onlyChacaltaya proton-onlyChacaltaya iron-onlyChacaltaya iron-onlyChacaltaya iron-onlyEAS-TOPKASCADEAkENO

Lo

g(d

I/d

E*E

2.5 )

(m-2

s-1sr

-1E

(GeV

)1.5 )

Log( E(GeV) )

Chacaltaya1992-1995r < 6m, err0QGSJET-model

END