Study of ion-irradiated polystyrene using slow positron beam

Depth profile of He+ ion-irradiated polystyrene was investigated by positron annihilation Doppler broadening spectroscopy and surface and interfacial cutting analysis system. S-parameter and electron spin resonance (ESR) intensity were measured for the samples kept in the air after the irradiation. Both S-parameter and the ESR intensity decreased with the lapse of time. It was also found by atomic force microscopy that the irradiated surface subsided by 0.15 μm. The density of the irradiated layer for the dose of 1×1016 ion/cm2 was estimated to be 0.6 g/cm3.