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

点击翻译按钮获取中文摘要

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.