宇宙線大氣簇射μ子定點密度及原初能譜“膝”的研究

劉俊, 耿慶熹, 楊洪濤, 劉長欽, 張品, 高曉宇, 經才騮, 查敏, 荊貴茹, 朱清棋, 張增, 吳本韓

Research output: Contribution to journalArticle

Abstract

用梁王山宇宙線觀測站的資料研究宇宙線大氣簇射 μ子定點密度譜,譜呈現明顯的拐折。通過MonteCarlo模擬,得到拐點對應的能量約為 1.7× 10 15eV ,拐點前後原初能譜指數差約為 0 .4 3,證實了KASCADE實驗 μ子定點密度譜呈現拐折的首次觀測結果,又一次推證了原初宇宙線能譜膝的存在。
With the extensive air shower (EAS) array at Mt. Liang Wang (735 g·cm², 245°N, 102.9° E, Kunming China) it is able to measure the muon density spectrum at a fixed distance from the core of EAS in the knee region. The spectra at two different fixed core distances (25m ≤ core distance < 30m, 30m ≤ core distance < 35m) were obtained from 4.4 × 10⁴ events collected in 1994 with criteria 5 × 10⁴ ≤ size ≤ 1.6 × 10⁷ and 10° ≤ θ < 30° that show obvious kinks. Monte Carlo simulations for the EAS development and detection with same selection criteria in the array triggering and the analysis procedure have been performed in order to relate the local muon densities to primary energy. As a result, we have deduced that the average position of the knee (Eknee) is at about 1.7×10¹⁵ eV and the average difference of the slopes of the primary energy spectrum before and after the knee (Δγ) is about 0.43. This work corroborates the first result (Eknee = 5PeV, Δγ = 0.3) reported by KASCADE. It authenticates reliably the existence of the knee at the primary energy spectrum by another composition of EAS - muon composition (more direct than electron composition). Based on the results obtained by two experiments, the difference of slopes of cosmic ray primary energy spectrum before and after the knee is close to 0.4 that is accepted widely, while the energy of the knee is different from the accepted 3PeV. Copyright © 2003 中國科學院高能物理研究所.
Original languageChinese
Pages (from-to)109-112
Journal高能物理與核物理
Volume27
Issue number2
Publication statusPublished - Feb 2003

Citation

劉俊、耿慶熹、楊洪濤、劉長欽、張品、高曉宇等(2003):宇宙線大氣簇射μ子定點密度及原初能譜“膝”的研究,《高能物理與核子物理》,27(2),頁109-112。

Keywords

  • 原初宇宙線能譜
  • μ子定點密度譜
  • Local muon density spectrum
  • Knee
  • Energy spectrum of primary cosmic rays
  • Alt. title: Study of EAS local muon density spectrum and the knee in the energy spectrum of primary cosmic rays