Positronium in room temperature ionic liquids

Hirade, Tetsuya  

The positron injected in insulating materials thermalizes at the end part of its track and forms Positronium (Ps) with one of excess electrons within 1 ps. Therefore, Ps formation can be a tool to investigate very fast processes like excess electron solvation in liquids. Many phenomena appeared in radiation chemistry researches for room temperature ionic liquids (ILs) are interesting and important for the application. Positron annihilation lifetime (PAL) measurements in ILs were carried out and anomalously long lifetime values of the shortest lifetime component were found in ILs. PAL and positron annihilation age-momentum correlation (AMOC) measurements were performed to clarify the reason of these anomalously long lifetime values and Ps bubble oscillation was finally discovered. Recent progresses are introduced with showing some results.