Study of High Energy Cosmic Rays in the Tibetan Highlands

青藏高原高能宇宙线研究

• 批准号: 07044064
• 负责人: YUDA Toshinori
• 金额: $ 10.75万
• 依托单位: The Univ.of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044064/
• 关键词: Tibet; Yangbajing; Air shower array; Celestial Gamma-ray source; Sun shadow; Burst detector; Primary proton component; Knee region; 一次宇宙線

In 1995, our air shower array, which has been operating at Yangbajing (4300 above sea level in Tibet as a collaboration experiment between Japan and China, was enlarged (the number of detectors increased from 65 to 221), and we are searching for 10 TeV celestial gamma-ray point sources and also studying the primary cosmic rays in ultra-high energy region. This is a unique air shower array capable of detecting 10 TeV cosmic rays with sufficient accuracy and we have already obtained a lot of important scientific results. Using the data obtained from this experiment, we obtained the primary energy spectrum in the energy region from 4x10^{14} to 2x10^{16} eV,showing a gradual steepening at around 2x10^{15} eV.This result will give a strong constraint to the mechanism of high energy cosmic ray acceleration. We also examined a yearly time variation of the Sun's shadow by cosmic rays in the period during 1990 through 1993 (corresponding to near maximum or declining phase of the solar activity cycle, and found that there exists a strong correlation between the movement of the sun's shadow and the phase of the solar activity. Eventually, our observation will obtain new information about the solar and interplanetary magnetic fields.In 1996, we also constructed a high density air shower array (detector separation is 7.5m) and a detector complex of emulsion chambers and burst counters with the total area of 80 m^2 near the center of the old array. The former is to search for supra TeV gammma ray sources and the latter is to observe the primary proton spectrum around the knee region and will be continued until summer of 1999. A preliminary results will be obtained around the end of this year since the data are now under analysis.

1995年，我们在青藏高原羊八井（海拔4300米）进行的中日合作实验中，对原有的空气簇射阵进行了扩建（探测器由65个增加到221个），并进行了10 TeV天体γ射线点源的搜寻和超高能区的初级宇宙线研究。这是一个独特的空气簇射阵列，能够以足够的精度探测10 TeV的宇宙射线，我们已经获得了许多重要的科学成果。利用该实验获得的数据，我们得到了4 × 10 ^{14}~ 2 × 10 ^{16} eV能区的初级能谱，在2 × 10 ^{15} eV附近，初级能谱逐渐变陡。这一结果将对高能宇宙线加速机制提供有力的约束。我们还考察了1990 ~ 1993年（对应于太阳活动周期的极大期或衰退期）宇宙线日影的年时间变化，发现日影的运动与太阳活动的位相有很强的相关性。1996年，我们还在旧阵列中心附近建造了一个高密度空气簇射阵列（探测器间距为7.5米）和一个由乳胶室和爆发计数器组成的探测器组合体，总面积为80平方米。前者是寻找超TeV γ射线源，后者是观测膝区附近的初级质子谱，将持续到1999年夏季。由于数据正在分析中，因此将在今年年底左右获得初步结果。

项目成果

M.Amenomori et al.: "Shadowing of cosmic rays by the Sun near maximum or at the decling phase of solar activity" The Astrophysical Journal,. (in press). (1996)

M.Amenomori 等人：“太阳活动接近最大值或衰退阶段时太阳对宇宙射线的阴影”《天体物理学杂志》。

M.Amenomori et al.: "Shadowing of cosmic rays by the Sun near maximum or at the declining phase of solar activity" ApJ. Vol.464. 954-958 (1996)

M.Amenomori 等人：“太阳活动接近最大值或衰退阶段时太阳对宇宙射线的阴影”ApJ。

C.S.Zhang, K.Kasahara and T.Yuda: "Neural network approach to obtain the primary proton flux at the knee from a hybrid-experiment of EC and AS array in Tibet" NIM. Vol.A376. 263-270 (1996)

C.S.Zhang、K.Kasahara 和 T.Yuda：“通过西藏 EC 和 AS 阵列混合实验获取膝部初级质子通量的神经网络方法”NIM。

M.Amenomori et al.: "Search for 10 TeV burst-like events coincident with the BATSE bursts using the Tibet air shower array" Astronomy and Astrophysics. 311. 919-926 (1996)

M.Amenomori 等人：“使用西藏空气簇射阵列搜索与 BATSE 爆发同时发生的 10 TeV 类爆发事件”天文学和天体物理学。

M.Amenomori et al.: "The cosmic ray energy spectrum between 10^<14.5>0^<16.3> eV covering the “Knee"region" The Astrophysical Journal,. 426(in press). (1996)

M.Amenomori 等人：“覆盖“膝盖”区域的 10^<14.5>0^<16.3> eV 之间的宇宙射线能量谱”《天体物理学杂志》，426（出版中）。