Secondary electron spectrum from 30 GeV to 10 TeV in the upper atmosphere

Yoshiko Komori, Tadashi Kobayashi, Kenji Yoshida, Jun Nishimura

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In the previous paper [1], we have evaluated the secondary electron spectrum in the upper atmosphere using our direct measurements of atmospheric gamma-ray spectrum in the 30 GeV- 10 TeV energy range. We have solved the simultaneous equations of electron and gamma-ray spectrum using the cascade shower theory combined by the gamma-ray production rate in the atmosphere. In this paper we present more precise solutions taking into account some nuclear decay modes, particularly, Dalitz decay mode which produces pair electrons directly from neutral pions, contributing about 10% to the secondary spectrum. The analytic results solved exactly are compared with those of the Monte Carlo simulation(MC), and the secondary electron/gammaray ratio shows the good agreement with each other. The contribution of Dalitz electrons increases the importance at the higher altitude, and cannot be negligible in the TeV electron balloon measurements. Our observed atmospheric gamma-ray spectrum is 20% higher than the results of MC as indicated previously [2], so that the estimates of secondary electrons become higher than 20% than those of MC. Although the discrepancy still remains, for the correction of primary electron spectrum we use the secondary spectrum obtained from the measured gamma-ray spectrum, because it does not include uncertainties of nuclear interaction models of MC.

Original languageEnglish
Title of host publication31st International Cosmic Ray Conference, ICRC 2009
PublisherUniversity of Lodz
Publication statusPublished - 2009
Event31st International Cosmic Ray Conference, ICRC 2009 - Lodz
Duration: 2009 Jul 72009 Jul 15

Other

Other31st International Cosmic Ray Conference, ICRC 2009
CityLodz
Period09/7/709/7/15

Fingerprint

upper atmosphere
gamma ray spectra
electrons
simulation
simultaneous equations
nuclear interactions
decay
balloons
high altitude
showers
cascades
pions
gamma rays
atmospheres
estimates

Keywords

  • Atmosphere
  • Nuclear interaction
  • Secondary electrons

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

Komori, Y., Kobayashi, T., Yoshida, K., & Nishimura, J. (2009). Secondary electron spectrum from 30 GeV to 10 TeV in the upper atmosphere. In 31st International Cosmic Ray Conference, ICRC 2009 University of Lodz.

Secondary electron spectrum from 30 GeV to 10 TeV in the upper atmosphere. / Komori, Yoshiko; Kobayashi, Tadashi; Yoshida, Kenji; Nishimura, Jun.

31st International Cosmic Ray Conference, ICRC 2009. University of Lodz, 2009.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Komori, Y, Kobayashi, T, Yoshida, K & Nishimura, J 2009, Secondary electron spectrum from 30 GeV to 10 TeV in the upper atmosphere. in 31st International Cosmic Ray Conference, ICRC 2009. University of Lodz, 31st International Cosmic Ray Conference, ICRC 2009, Lodz, 09/7/7.
Komori Y, Kobayashi T, Yoshida K, Nishimura J. Secondary electron spectrum from 30 GeV to 10 TeV in the upper atmosphere. In 31st International Cosmic Ray Conference, ICRC 2009. University of Lodz. 2009
Komori, Yoshiko ; Kobayashi, Tadashi ; Yoshida, Kenji ; Nishimura, Jun. / Secondary electron spectrum from 30 GeV to 10 TeV in the upper atmosphere. 31st International Cosmic Ray Conference, ICRC 2009. University of Lodz, 2009.
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abstract = "In the previous paper [1], we have evaluated the secondary electron spectrum in the upper atmosphere using our direct measurements of atmospheric gamma-ray spectrum in the 30 GeV- 10 TeV energy range. We have solved the simultaneous equations of electron and gamma-ray spectrum using the cascade shower theory combined by the gamma-ray production rate in the atmosphere. In this paper we present more precise solutions taking into account some nuclear decay modes, particularly, Dalitz decay mode which produces pair electrons directly from neutral pions, contributing about 10{\%} to the secondary spectrum. The analytic results solved exactly are compared with those of the Monte Carlo simulation(MC), and the secondary electron/gammaray ratio shows the good agreement with each other. The contribution of Dalitz electrons increases the importance at the higher altitude, and cannot be negligible in the TeV electron balloon measurements. Our observed atmospheric gamma-ray spectrum is 20{\%} higher than the results of MC as indicated previously [2], so that the estimates of secondary electrons become higher than 20{\%} than those of MC. Although the discrepancy still remains, for the correction of primary electron spectrum we use the secondary spectrum obtained from the measured gamma-ray spectrum, because it does not include uncertainties of nuclear interaction models of MC.",
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AU - Kobayashi, Tadashi

AU - Yoshida, Kenji

AU - Nishimura, Jun

PY - 2009

Y1 - 2009

N2 - In the previous paper [1], we have evaluated the secondary electron spectrum in the upper atmosphere using our direct measurements of atmospheric gamma-ray spectrum in the 30 GeV- 10 TeV energy range. We have solved the simultaneous equations of electron and gamma-ray spectrum using the cascade shower theory combined by the gamma-ray production rate in the atmosphere. In this paper we present more precise solutions taking into account some nuclear decay modes, particularly, Dalitz decay mode which produces pair electrons directly from neutral pions, contributing about 10% to the secondary spectrum. The analytic results solved exactly are compared with those of the Monte Carlo simulation(MC), and the secondary electron/gammaray ratio shows the good agreement with each other. The contribution of Dalitz electrons increases the importance at the higher altitude, and cannot be negligible in the TeV electron balloon measurements. Our observed atmospheric gamma-ray spectrum is 20% higher than the results of MC as indicated previously [2], so that the estimates of secondary electrons become higher than 20% than those of MC. Although the discrepancy still remains, for the correction of primary electron spectrum we use the secondary spectrum obtained from the measured gamma-ray spectrum, because it does not include uncertainties of nuclear interaction models of MC.

AB - In the previous paper [1], we have evaluated the secondary electron spectrum in the upper atmosphere using our direct measurements of atmospheric gamma-ray spectrum in the 30 GeV- 10 TeV energy range. We have solved the simultaneous equations of electron and gamma-ray spectrum using the cascade shower theory combined by the gamma-ray production rate in the atmosphere. In this paper we present more precise solutions taking into account some nuclear decay modes, particularly, Dalitz decay mode which produces pair electrons directly from neutral pions, contributing about 10% to the secondary spectrum. The analytic results solved exactly are compared with those of the Monte Carlo simulation(MC), and the secondary electron/gammaray ratio shows the good agreement with each other. The contribution of Dalitz electrons increases the importance at the higher altitude, and cannot be negligible in the TeV electron balloon measurements. Our observed atmospheric gamma-ray spectrum is 20% higher than the results of MC as indicated previously [2], so that the estimates of secondary electrons become higher than 20% than those of MC. Although the discrepancy still remains, for the correction of primary electron spectrum we use the secondary spectrum obtained from the measured gamma-ray spectrum, because it does not include uncertainties of nuclear interaction models of MC.

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