Positronium formation at the terminal spur of positron track; Delayed positronium formation in fused quartz

Komuro, Yo; Hirade, Tetsuya  ; Suzuki, Ryoichi*; Odaira, Toshiyuki*; Muramatsu, Makoto*; Suzuki, Takenori*

The injected positrons to condensed materials form a very small area where they deposit much energy and some tens of ion-electron pairs are formed. This area is called a positron spur or blob. Positrons have a possibility to form positronium at this area. Some of the positrons are isolated from the excess electrons when they thermalized. They will have smaller possibility to form positronium and longer time to form positronium. Therefore the positronium formation by the isolated positrons from excess electrons can be easily inhibited by applying the external electric fields. We have found this expected phenomena by applying the external electric fields.