"Study on the Origin of High Energy Cosmic Ray Nuclei by Analyzing the Data from Antarctic Long Duration Balloon Experiments"

本研究的目的是研制一套核乳胶板自动扫描系统，研究100 TeV/粒子能区宇宙线核的成分。在第一年，我们开发了一个分析系统，借助显微镜和PC机上的CCD摄像机和AD单元，对照相乳胶板中带电粒子径迹的显微照片进行分析。并将其应用于入射核电荷测定的标定中，计算乳胶层径迹吸收的光量。在第二年，已经开始使用我们的新系统分析南极长期气球暴露的数据。分析集中在高能量事件，以避免由于高背景粒子噪声的缺陷。到目前为止，已经完成了大约60个最高能量事件的初级粒子识别。分析工作尚未完成，但我们的第一个目标，即建立一个乳液实验室，用于分析长期实验的数据，已经至少实现。通过对前期观测数据的整理和重新分析，我们公布了宇宙线质子和氦能谱，包括首次南极气球实验的初步观测数据。作为对宇宙线相互作用（包括反常的电子对）的重新研究结果，报道了新中性玻色子衰变假说的可行性。

The objective of this research is to develop an auto-scanning system of nuclear emulsion plates, and to study on the composition of cosmic ray nuclei in the energy region of 100 TeV/particle. In the first year, we developed an analysis system to digitize a photomicrograph of the charged particle tracks in photographic emulsion plates with the aid of CCD camera and AD unit on a microscope and PC. And it has been applied to the calibration for charge determinations of incident nuclei to calculate the amount of light to be absorbed by the track in the emulsion layer. In the second year, the analysis of the data from Antarctic Long Duration Balloon Exposure has been started using our new system. The analysis has been concentrated on only high-energy events to avoid the defect due to high-back-ground particle noise. So far the primary particle identification of about 60 highest energy events has been done. The analysis is not completed yet, but our first objective to built an emulsion laboratory for analyzing the data from Long-Duration-Balloon-Experiments has been at leased achieved. Regarding with compilation and re-analysis of our previous data, cosmic-ray proton and helium energy spectra including the preliminary data from first Antarctic Balloon Experiment has been published. And as results of re-examination on the cosmic ray interactions, which include anomalous number of electron pairs, the feasibility of a hypothesis of a decay of new neutral boson has reported.