THE OBSERVATION OF PRIMARY COSMIC-RAY BY JAPAN-RUSSIA COORPORATIVE BALLOON EXPERIMENT

这项实验自1995年以来一直在随意地进行，目的是为了弄清楚宇宙线能谱中所谓的“膝”，它是光谱倾角的快速变化。1995年进行了两次从堪察加到伏尔加河的长时间气球飞行，1996年两次，1997年三次，共9次飞行，成功观测了宇宙射线。通过双方的互访，对回收小室的拆解、X线片和核乳剂的处理、分析策略的讨论和分析数据的比较进行了讨论。这些通过互访进行的讨论和合作工作对研究的进展很有成效。此外，日俄双方都开发了一种由显微镜、精密工作台和计算机组成的新的自动测量系统。该系统实现了将梯级簇射追溯到核乳剂顶点的繁琐工作的演绎，为我们提供了大量的长期观测数据的分析能力，我们已经完成了对1995年观测的数据分析，得到了按化学成分分类的能谱。统计数据还不够，但计算结果与低能区的能谱有很好的一致性。1997年在南非达文举行的国际宇宙射线会议上报告了这些结果，证明了能量和电荷测定的方法论。利用上述新系统对1996年和1997年的观测资料进行了分析处理，可望在今年夏天得到结果。

This experiment has been carried out amually since I995, for the purpose of making clear so called "knee" in the cosmic-ray energy spectrum which is a rapid change in an inclination of spectrum. Long duration balloon flights from Kamchatka to Volga River were earried out twice in 1995, twice in 1996 and three times in 1997, and 8 flights in total 9 flights were succeeded in the observation of cosmic-ray. The disassembly of recovered chamber, proccessing of x-ray film and nuclear emulsion, the discussion about the policy of analysis and the comparison of analized data were performed through the mutual visit by both side. These discussions and cooperative works through mutual visit were quite effective for the progress in reaserach.Moreover, both side of Japanese and Russian group developed a new auto measuring system which consists of a microscope, precision stage and computer. This system realized the deduction of laborous work in the tracing back of the cascade shower to the vertex point in the nuclear emulsion, and give us a large capacity for the analysis of a large amount of data by the long dulation observation.We have already finished the data analysis for the observation in 1995 and obtained the energy spectra classified by chemical composition. The statistics is not enough but the results shows a good consistency with the energy spectra in low energy region. Convining the methodology as the energy and charge determination, these results were reported in 1997 international cosmic-ray conference held in Darvan, South Africa. The data processing for the 1996 and 1997 observation is under the analysis by use of the above mentioned new system, and the results are expected to be obtained in this summer.