Delocalized radiation damage in polymers

We present and discuss measurements of electron-irradiation damage in polystyrene and other polymers, based on fading of the 7-eV energy-loss peak. These measurements suggest a large increase in characteristic dose as the electron-beam diameter is reduced from 1 μm to below 1 nm. This finding is discussed in terms of secondary-electron production and delocalization of the inelastic scattering, both as it affects the volume of specimen in which the energy is deposited and the volume giving rise to the inelastic signal used to assess the damage.

► This work confirms and extends previous observations of a dramatic increase in the measured characteristic dose for damage to polymers in the case of small (sub-micron) electron probes.
► The effect is shown to depend directly on electron-probe diameter rather than current density.
► The effect is discussed in terms of damage by secondary electrons and delocalization of the inelastic scattering used to observe the damage.