A Study of Neutral Particles from Cygnus X-3 above 10^<18>eV

占地面积100平方公里的秋野巨型风淋阵（AGASA）自1990年以来一直在运行。这个新阵列积累的事件数量比20km^2的观测次数要多，20km^2已经运行了5年多。对1991年11月的数据进行分析，以寻找天鹅座X-3方向上的过量现象，结果显示，在1991年1月的强射电暴之后，一个月的事件数量增加了4西格玛。没有其他时间段显示出明显的过剩。AGASA的累积数据集显示，天鹅座X-3方向有2.5sigma的过剩，仍然低于强有力地主张源发射的必要水平。需要更多的数据来阐明天鹅座X-3中性辐射的特征。我们用几种方法改进了实验，以提高对中性源发射的灵敏度。安装一个探测器校准系统，使我们有更好的上升时间和增益确定性。可探测到的阵雨的阈值能量已经降低到10^<17>eV，由此产生的触发率更低（-0.1Hz）。中心实验室的新工作站收集数据并将数据写入磁光盘。这些在线系统由我们在东京的研究所使用电信进行监测和控制。在测量定向过剩、测试周期性和寻找爆发的分析上也作了改进。

The Akeno Giant Air Shower Array (AGASA), covering 100km^2 area, has been in operation since 1990. This new array has accumulated more events than the number observed with the 20km^2 which has been in operation for over 5 years. Analysis of the data up through Nov 1991 to lood for excess in the direction of Cygnus X-3 shows 1 month that has a 4sigma excess number of events, occuring right after the strong radio burst of Jan 1991. No other time period shows a significant excess. The cummulative data set of AGASA shows a 2.5sigma excess in the direction of Cygnus X-3, still lower than necessary to make a strong claim for source emission. More data will be needed to clarify the characteristics of neutral emission from Cygnus X-3.We have improved the experiment in several ways to enhance sensitivity to neutral source emission. Installation of a detector calibration system gives us better rise time and gain certainty. The threshold energy of detectable showers has been decreased down to 10^<17>eV and the resulting trigger rate is lower (-0.1Hz). A new workstation in the central laboratory collects and writes the data to Magnetic Optical disks. These on-line systems are monitored and controlled from our Institute in Tokyo using telecommunications. Improvements have been made on analysis which have been used to measure the directional excess, test for periodicity, and search for bursts.