No abstract

The possibility of a simultaneous thermal release of electrons and holes in the tliermoluminescence (TL) process was suggested in the early stages of the development of this discipline. However, most investigators utilized a model in which carriers of only one kind are thermally released from their "traps". I n this model these carriers then radiatively recombine with carriers of opposite charge in "luminescence centers". This paper presents the results of a theoretical investigation into a more complex model, which allows the thermal release of electrons and holes in the same temperature range.The solution of a set of four simultaneous differential equations is required in this investigation. The equations are not amenable to analytical solution, so the equations are solved numerically for given values of the model parameters. Conclusions are drawn about the shapes of the TL curves, and the expected stability of the corresponding traps a t given temperatures, and the apparent effective parameters namely, the activation energy, the frequency factor, and the order of kinetics, are obtained using the "general order" formalism. In all cases examined, there is a good three parameter fit to the TL peak generated by the examined model. This shows that even a rather general TL peak can be described quite accurately by the three parameter model. The activation energy determined using the three parameter analysis is found to agree rather well with the input activation energy of trapped electrons which is used in the original peak generation for the particular cases examined. I n cases where the activation energy for holes is small,.the glow peaks occur a t relatively low temperatures, and are characterized by a very high effective frequency factor in the three parameter analysis. Furthermore, several cases are studied in which the calculated kinetics order is found to be less than 1.0.La possibilitk d'une liberation thermique simultanke des electrons a t des trous dana le processus de thermoluminescence avait 6tk suggkrke dans lea premieres ktapes du dkveloppement de cette discipline; mais la plupart des chercheurs ont prkfkr6 utiliser le modde plus restrictif oii un seul type de porteur de charge est libere thermiquement des pieges pour ensuite se recombiner avee des porteurs de signe oppos6 dans les "centres". Dans cet article, nous traitons le cas plus complexe oh les electrons et les trous peuvent btre libkrks dans le mbme domaine de tempbrature. Cela appelle la solution d'un systbme de quatre equations differkntielles simultankes, ce qu'on ne sait bien faire analytiquement. Au lieu de cela, c'est une methode numeriquk que nous utilisons pour rksoudre ce systeme d'equations pour des valeurs donnkes des parambtres. Nous sommes ainsi parvenu Zt des conclusions, concernant la forme des courbes de TL obtenues, la stabilitk des pikges correspondants it attendre des temperatures donnkes, et les valeurs effectives des parambtres qu on pourrait dkduire d une approche par la methode de "l'ordre gknkral"; savoir, l'energie #act...