Age-momentum correlation experiments on industrial grade diamond

Age-momentum correlation (AMOC) measurements as a function of temperature have been carried out on a large industrial grade diamond. The measurements were performed from room temperature up to 1120 K with the sample being heated by a pair of incandescent lamps. The temperatures sampled represent three separate domains for diffusion processes in diamond. Although no clear temperature dependence was evident in the positron lifetime or in the Doppler broadening of the annihilation radiation, an optically or thermally induced reversible change of the electronic structure of certain centres in the lattice was observed. An analysis of the data in terms of the two-state trapping model allowed the effect to be observed in the lifetime of the first component, in the trapping rate and in the intensity of the trapped state. The results demonstrate the potential of the positron to probe electronic transitions at defects in the bulk of the diamond lattice.