Thermal positron interactions with alkali covered tungsten

• DOI: 10.1016/j.nimb.2016.10.008
• Publication Date: 2016-10-17T08:16:10Z
• Authors: Takashi Yamashita; Shimpei Iida; Hiroki Terabe; Yasuyuki Nagashima
• Keywords: Positronium

Abstract The branching ratios of positron reemission, positronium emission, positronium negative ion emission and capture to the surface state for thermalized positrons at polycrystalline tungsten surfaces coated with Na, K and Cs have been measured. The data shows that the ratios depend on the coverage of the alkali-metal coating. The fraction of the emitted positronium increases with the coverage of the coating up to 90%.