Afterglow, TL and IRSL in beta-irradiated HPHT type Ib synthetic diamond

The presence of nitrogen or other impurities in HPHT type Ib synthetic diamond may produce shallow or deep localized trapping states for electrons (holes) with activation energies below the conduction (above the valence) band. The present work deals with room temperature afterglow (AG), thermoluminescence (TL) and infrared-stimulated luminescence (IRSL) in HPHT type Ib diamond. The existence of vacancy impurity-related defects gives rise to a characteristic AG, TL and IRSL in beta-irradiated samples. The AG luminescence decays fast, decreasing to about 10(3) of its initial intensity value in 100 s. The deconvoluted TL glow curve is composed of a 1.4-order peak at 375 K and three first-order kinetics peaks at 442, 475 and 514 K. The IRSL was excited with 830 nm light releasing electrons from the trapping states with different efficiencies. The TL glow curve was found to be non-reproducible because the multiple impurity-related defects induced by irradiation are unstable at temperatures around 800 K. The peculiar AG and TL behavior observed in the investigated HPHT type Ib synthetic diamond may hinder its application in TL dosimetry. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.