Influence of radiation-induced species on positronium formation in poly(methylmethacrylate) at low temperature
- 作者：Tashiro ; M. ; Tseng ; C.Y. ; Seki ; S. ; Honda ; Y. ; Tagawa ; S.
- 关键词：Positronium formation ; Poly(methylmethacrylate) (PMMA) ; Anion radical
- 刊名：Radiation Physics and Chemistry
- 出版年：2003
- 期刊代码：68_0969806x
- 类别：ph
- 出版时间：October - November, 2003
- 卷：68
- 期：3-4
- 页码：475-479
- 文件大小：360 K
摘要
Impurity effect, elapsed time dependence, visible light bleaching effect, and temperature dependence on positronium formation probabilities were measured at temperatures ranging from 25 to 300K for poly(methylmethacrylate) (PMMA). In order to clarify the radiation-induced species, IR–UV absorption spectra were obtained as a function of temperature for PMMA irradiated at 77K. PMMA anion radical was stable at low temperatures. It is suggested that PMMA anion radical and both MMA monomer and dimmer anion radicals strongly contribute to Ps formation at low temperatures.