Author/Authors :
Yang، نويسنده , , J. and Li، نويسنده , , Z.X. and Zhao، نويسنده , , B.Z. and Zhang، نويسنده , , P. and Lu، نويسنده , , E.Y. and Zhang، نويسنده , , J. and Yuan، نويسنده , , D.Q. and Cao، نويسنده , , X.Z. and Yu، نويسنده , , R.S and Wang، نويسنده , , B.Y.، نويسنده ,
Abstract :
Gamma irradiation effect on annihilation characteristics of positronium and free positron in tetrafluoroethylene–perluoro (alkoxy vinyl ether) copolymer (PFA) were studied independently by age momentum correlation (AMOC) and the correlation between Doppler broadening S parameter and o-Ps fraction (S–Io-Ps correlation). AMOC results revealed decreases in S parameter of o-Ps, owing to accumulation of polar atoms around free volume. S–Io-Ps correlation indicated a reduced intrinsic S parameter of free positron in irradiated PFA, which was caused by enhanced positron trapping on polar atoms due to densification of local segments and variation in the elemental environment around free volumes.
