α-Al2O3 crystals were subjected to different thermal treatments at 1500C in a

strongly reducing ambience of carbon and vacuum. Positron annihilation spectroscopy and thermally stimulated luminescence studies were carried out in

order to understand the nature of defects generated. Results showed the presence of

aluminium vacancies in crystals annealed in vacuum. On annealing in the presence

of graphite, ingress of carbon in these vacancies was indicated by different PAS

measurements. A simultaneous enhancement of dosimetry properties was observed.

The study provides evidence that association of carbon with aluminium vacancies

helps in creation of effective dosimetry traps.

Positron Annihilation and Thermoluminescence Studies of Thermally Induced

Defects in α-Al2O3 Single Crystals. K.P.Muthe, K.Sudarshan, P.K.Pujari,

M.S.Kulkarni, N.S.Rawat, B.C.Bhatt, S.K.Gupta: Journal of Physics D, 2009,

42[10], 105405