Study of Ultra-high Energy Cosmic Rays at Tibetan Highlands

青藏高原超高能宇宙线研究

• 批准号: 01044039
• 负责人: YUDA Toshinori
• 金额: $ 3.84万
• 依托单位: Institute for Cosmic Ray Research, University 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: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01044039/
• 关键词: Air shower array; Yangbajing; Gamma ray point source; Fast timing; Scintillation counter; TKO; Cyg. X-3

A new air shower experiment, aiming to search for celestial gamma ray point sources, has been started from 1989 with Chinese scientists at Yangbajing (4,300m a. s. l., 90.5^ﾟE and 30.1^ﾟN) in Tibet. The present array consists of 49 scintillation counters for fast timing (FT), each of which has an area of 0.5 m^2 and is placed in a grid pattern with a spacing of 15 m. Other 16 density counters surround the FT counter array to select the showers whose core fall inside the array. The TKO and CAMAC system, controlled by a 32 bit micro-computer, is employed in this experiment. The data are recorded on a 8 mm video tape of about 2 GB capacity. A Rb clock with a stability of <54 mus/month is equipped to receive the arrival time of air showers precisely. The operation, atarted fully from June of 1990, is now successively continued with a high trigger rate of about 20 Hz to search for gammaray point sources in the energy region lower than 100 TeV. For the time being, only our array can detect s … More uch rather low energy gamma-rays effectively, since the observation site is located at high altitude.The performance of the present array was examined by using the experimental data, comparing those with a Monte Carlo simulation. This shows that the arrival direction of air showers can be determined with an angular resolution of about 0.5^ﾟ at 100 TeV. Also the energy resolution is estimated to be about 30% for a 100 TeV gamma ray. The detectable shower energy is estimated to be about 20 TeV, and the non-bias energy corresponds to about 40 TeV for gamma ray showers. Our experiment is therefore considered to have a distinctive feature among a lot of air shower arrays working now in the world, giving a capability of observing gamma ray point sources in the several 10 TeV energy region where both of mirror and array experiment on the ground are inaccessible.We still need to operate this array at least for more than one year to examine whether Cyg. X-3 and other point source candidates really emit high energy gamma rays steadily or not. The first result will be given in this fall. Less

从1989年起，中国科学家在西藏羊八井(4300米，S，L，90.5^ﾟE和30.1^ﾟN)开始了一项新的大气簇射实验，目的是寻找天体伽马射线点源。目前的阵列由49个用于快速计时(FT)的闪烁计数器组成，每个闪烁计数器的面积为0.5m^2，并以15m的间隔排列成栅格图案。其他16个密度计数器围绕FT计数器阵列，以选择其核心落在阵列内的簇射。本实验采用32位微型机控制的TKO和CAMAC系统。数据被记录在约2 GB容量的8 mm录像带上。RB时钟的稳定度为&lt；54mus/月，可精确接收空气骤雨的到达时间。这次行动从1990年6月开始，现在以20赫兹左右的高触发率陆续进行，以寻找低于100TeV能区的伽马雷点源。目前，只有我们的阵列可以检测到S…利用实验数据对该阵列的性能进行了检验，并与蒙特卡罗模拟结果进行了比较。这表明，在100TeV时，空气簇射的到达方向可以用大约0.5^ﾟ的角分辨率来确定。此外，对于100TeV的伽马射线，能量分辨率估计约为30%。可探测的簇射能量估计约为20TeV，对于伽马射线簇射，无偏置能量约为40TeV。因此，我们的实验被认为是目前世界上许多工作的空气簇射阵列中的一个显著特点，使我们能够在几个10TeV能区观测伽马射线点源，在那里无法进行地面反射镜和阵列实验。我们还需要运行这个阵列至少一年以上来检查Cyg。X-3等点源候选者是否真的稳定地发射高能伽马射线。第一个结果将在今年秋天公布。较少

项目成果

雨森 道紘 他: "Status and performance of the AS array of the Tibet ASγ experiment," AIP国際会議論文集(米国物理学会). (1991)

Michihiro Amemori 等人：“西藏 ASγ 实验的 AS 阵列的状态和性能”，AIP 国际会议论文集（美国物理学会）（1991 年）。

M. Amenomori et al.: "Status and performance of the AS array of the Tibet AS gamma experiment" AIP Conference papers,. (1991)

M. Amenomori 等人：“西藏 AS 伽玛实验的 AS 阵列的现状和性能”AIP 会议论文，。

A. X. Huo et al.: "Tibet AS gamma experiment" Proc. of 21st International Cosmic Ray Conf., Adelaide, 1990. 2. 427-430 (1990)

A. X. Huo等：“西藏AS伽马实验”Proc.

K. Hibino et al.: "A new project to search for high energy gamma ray point sources in Tibet" Nuclear Physics B (Proc. Suppl). 10B. 219-227 (1989)

K. Hibino 等人：“在西藏寻找高能伽马射线点源的新项目”核物理 B（Proc. Suppl）。