Abstract
The room-temperature kinetics of colouring in NaCl:Mn2+ has been investigated as a function of concentration and aggregation state of manganese. The colouring rates for quenched and as-grown samples are similar at very low dose, but the colouring curves differ markedly at higher dose, the colouring being higher for as-grown samples. The initial F-colouring increases with Mn concentration up to approximately 90 ppm where it roughly saturates. The thermal stability of F centres is greater in as-grown than in quenched samples in accordance with the shift of the thermoluminescence glow peaks to higher temperatures. A prominent band at 220 nm is formed under irradiation in proportion to the concentration of cation vacancies existing prior to irradiation. The kinetics of growth under irradiation and the thermal annealing behaviour of various Mn centres has also been investigated. No linear correlation has been found between the concentration of F-centres created and Mn2+ vacancy dipoles destroyed during irradiation.