Dose effect in neutron-irradiated C60: a positron lifetime spectroscopy and DSC study

Polycrystalline C60 samples irradiated with five doses of nuclear reactor neutrons stretching from 2.44 × 1014 to 1.03 × 1018 n/cm2 were investigated by positron annihilation spectroscopy and DSC. The measurements indicated that the crystal structure of buckminsterfullerene is unaffected up to a dose of about 7.56 × 1016 n/cm2. Above that dose the crystal lattice begins to collapse and at a dose of 1.03 × 1018 n/cm2 the structure becomes totally disordered.