CERN Accelerating science

Article
Report number	arXiv:1210.2813
Title	Observations of High Energy Cosmic-Ray Electrons from 30 GeV to 3 TeV with Emulsion Chambers
Author(s)	Kobayashi, T. (Sagamihara, Aoyama Gakuin U.) ; Komori, Y. (Yokosuka, U. Human Serv.) ; Yoshida, K. (Shibaura Inst. Tech.) ; Yanagisawa, K. (Shibaura Inst. Tech.) ; Nishimura, J. (JAXA, Sagamihara) ; Yamagami, T. (JAXA, Sagamihara) ; Saito, Y. (JAXA, Sagamihara) ; Tateyama, N. (Kanagawa U.) ; Yuda, T. (Tokyo U., ICRR) ; Wilkes, R.J. (Washington U., Seattle)
Publication	2012
Imprint	11 Oct 2012
Number of pages	38
Note	Comments: 38 pages, 10 figures, 3 tables, Accepted for publication in ApJ 38 pages, 10 figures, 3 tables, Accepted for publication in ApJ
In:	Astrophys. J. 760 (2012) 146
DOI	10.1088/0004-637X/760/2/146
Subject category	Astrophysics and Astronomy
Accelerator/Facility, Experiment	CERN SPS CERN SPS
Test beam	H4
Abstract	We have performed a series of cosmic-ray electron observations using the balloon-borne emulsion chambers since 1968. While we previously reported the results from subsets of the exposures, the final results of the total exposures up to 2001 are presented here. Our successive experiments have yielded the total exposure of 8.19 m^2 sr day at the altitudes of 4.0 - 9.4 g/cm^2. The performance of the emulsion chambers was examined by accelerator beam tests and Monte-Carlo simulations, and the on-board calibrations were carried out by using the flight data. In this work we present the cosmic-ray electron spectrum in the energy range from 30 GeV to 3 TeV at the top of the atmosphere, which is well represented by a power-law function with an index of -3.28+-0.10. The observed data can be also interpreted in terms of diffusive propagation models. The evidence of cosmic-ray electrons up to 3 TeV suggests the existence of cosmic-ray electron sources at distances within  1 kpc and times within  1x10^5 yr ago.
Copyright/License	arXiv nonexclusive-distrib. 1.0

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