Abstract

• The purpose of this research is to identify the decay branching ratios of five radioisotopes in thorium decay chain from their measured ranges and kinetic energies. Totally 50 thorium decay series events which were detected in nuclear emulsion of plate #5, Module #26 in J-PARC E07 experiment were analyzed. The type of radioisotopes of alpha emitters were identified with measured range and the range in emulsion obtained from empirical formula and Barkas’ literature. Moreover, branching ratio for the radioisotopes of alpha emitters in thorium decay series events were obtained from their measured ranges and corresponding kinetic energies. The results are consistent with the results in Barka’s literature.