Kerma rate effects on thermoluminescent response of CVD diamond.

The thermoluminescence (TL) response of chemical vapour deposition diamond is studied after X-irradiation (45 kV) at room temperature for various air kerma rates ranging from 0.7 to 100 Gy.min(-1). For a given air kerma, the TL signal as a function of air kerma rate exhibits large variations and is higher for low air kerma rates than for higher ones. In order to explain these results, the simplest energy-level scheme has been considered, that is, with only one electron trap and one recombination centre. Kinetic equations are numerically solved. Calculations are made for various electron-hole generation rates and show that the trap filling as a function of electron-hole generation rate follows, actually, the same evolution as the one of experimental TL response. The kerma rate effect on TL response is explained by the competitivity between the recombination and the trapping processes during irradiation.