Study of High Energy Cosmic Particles in Tibet

自1995年以来，西藏- ii型空气阵雨阵列在西藏羊八井（海拔4300米）运行，用于寻找10 TeV伽玛射线点源，以及高能宇宙射线的研究。1996年，在“藏- 2”号内部还设置了高密度空气阵雨阵列，其探测器放置在7.5 m栅格上，用于探测能量在3 TeV以上的阵雨事件。随着高密度风淋阵的出现，我们首次用传统的风淋阵探测到蟹状星云的信号。此外，我们还成功地探测到了1997年处于非常高状态的AGN Mrk501的信号。在1996年夏季至199g夏季进行了空气淋点阵列与核心探测器（由乳化液室和爆炸探测器组成）的混合实验。铁芯检测仪的总面积为80m2。对包含在空气簇淋中的一束高能粒子的观测提供了关于初级粒子中质子成分的直接信息。利用人工神经网络方法对爆炸探测器获得的数据集进行处理，得到了200tev ~ 1000tev之间的质子能谱。1999年秋天，我们建造了一个新的空气淋室阵列，由545个探测器组成，放置在一个7.5米的正方形网格上。探测器阵列的有效覆盖面积约为22000平方米。淋浴的阈值能量约为3 TeV，触发频率约为700 Hz。该阵列自1999年11月中旬开始运作。

Since 1995, an air shower array (Tibet-II) has been operating at Yangbajing (4,300m above sea level) in Tibet to search for 10 TeV gamma-ray point sources, as well as to study the primary cosmic rays at high energies. In 1996, a high density air shower array whose detectors are placed on a 7.5 m grid was also set up inside the Tibet-II to detect shower events with energy above 3 TeV. With the advent of this high density air shower array, a signal from the Crab Nebula has been detected for the first time with a conventional air shower array. Furthermore, we also succeeded to detect signals from the nearby AGN Mrk501 which was in a very high state in 1997.A hybrid experiment of air shower array and core detector (consisting of emulsion chambers and burst detector) was done during the period from 1996 summer through 199g summer. The total area of the core detector is 80 m2. Observation of a bundle of high energy particles contained in the air shower provides a direct information about the proton component in the primary particles. Applying an artificial neural network method to the data set obtained from the burst detectors, we obtained the energy spectrum of protons between 200 TeV and 1000 TeV.In the fall of 1999, we constructed a new air shower array consisting of 545 detectors which are placed on a 7.5 m square grid. The effective area covering the detector array is about 22,000 m2. The threshold energy of showers is about 3 TeV and the trigger rate is about 700 Hz. The array has been operated since the middle of November 1999.