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

Akeno巨型空气簇射阵列(AGASA)占地100平方公里，自1990年以来一直在运行。这个新的台阵积累了比已经运行了5年多的20 KM^2台阵观测到的更多的地震。对截至1991年11月的天鹅座X-3方向的超额观测数据的分析表明，在1991年1月的强射电爆发之后的1个月中，天鹅座X-3的超额事件数为4西格玛。没有其他时间段显示出显著的超额。AGASA的累积数据集显示，在天鹅座X-3方向上有2.5西格玛过剩，仍然低于提出强烈来源排放要求所需的水平。需要更多的数据来阐明天鹅座X-3中性发射的特征。我们已经在几个方面改进了实验，以提高对中性源发射的灵敏度。探测器校准系统的安装给我们提供了更好的上升时间和获得的确定性。可探测簇射的阈值能量已降至10^&lt；17&gt；eV，由此产生的触发频率更低(-0.1赫兹)。中心实验室的一个新的工作站收集数据并将其写入磁光盘。这些在线系统是我们东京研究所使用电信进行监测和控制的。对用于测量方向过剩、测试周期性和搜索脉冲串的分析进行了改进。

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.