Automatic track following system to study double strangeness nuclei in nuclear emulsion exposed to the observable limit

摘要

An automatic track following system has been successfully developed to follow tracks in nuclear emulsion sheets exposed with beam up to the limit to be observed for the first time. The track followed rate of the system is 99.5% with the assistance of the new techniques. The working speed for a track is less than 1 min through one thick emulsion sheet, whereas it is 15 times faster than that of semiautomatic system with human. The system working for 24 h is applied for the E07 experiment at J-PARC and makes it possible to detect ~10~2 nuclei with double strangeness (S=-2 nuclei) within one year. Regarding analyses to identify nuclear species of S=-2 nuclei, the system shows quite decent job for significant steps such as following tracks emitted to spherical directions from S=-2 nuclei, measurement of lengths of followed tracks, and so on.