β-delayed fission of 228Ac

摘要

The basic process of an exotic decay mode namely β-delayed fission is simply introduced.The progress status of the study in the world is essentialized.The observation of β-delayed fission of 228Ac is reported.The radium was radiochemically separated from natural thorium.Thin Ra sources in which 228Ac was got through 228Ra→β- 228Ac were prepared for observing fission fragments from β-delayed fission of 228Ac.They exposed to the mica fission track detectors,and measured by an HPGe γ-ray detector.The β-delayed fission events of 228Ac were observed and its β-delayed fission probability was found to be (5±2)×10-12.