Ion-Temperature Measurements of Fission-Fragment Tracks in CsBr Films

Abstract

The velocity spectrum of ${\mathrm{Cs}}^{+}$ and ${\mathrm{Br}}^{-}$ ions emitted from thin CsBr films irradiated with fission fragments show that the ions are not ejected by direct collisional interactions with the fission fragments but appear to be thermionically emitted with an average temperature of 6.6 × ${10}^4$ K. This suggests the existence of a transient hot thermal core within the fission fragment track. Transient fission tracks in condensed phases may be convenient media for studying fast high-temperature atomic and molecular interactions.