Recombination lifetimes of LiF:Mg,Cu,P for pulsed optically stimulated luminescence

Highlights: • Lifetimes of 22.8 μs and 60 μs dominate radiative recombination in LiF:Mg,Cu,P. • Relative signal levels of recombination channels change with stimulation time. • Different recombination channels in LiF:Mg,Cu,P show the same thermal stability. • Following stimulation, > 70% of the total luminescence recombine within 300 μs. The well-known thermoluminescent material LiF:Mg,Cu,P (MCP) was previously shown to emit significant optically stimulated luminescence (OSL). In this paper, we investigate the rate of OSL recombination processes in MCP, expressed as effective lifetimes, using time-correlated single photon counting, in this context often referred to as time-resolved pulsed OSL. The recombination luminescence fell into two categories: (i) a dominant fast decaying luminescence described by the two lifetimes ${\tau }_1=22.8\left(1.7\right)\mathrm{\mu s}$ and ${\tau }_2=60\left(5\right)\mathrm{\mu s}$ and (ii) a slowly decaying part with indeterminate decay profile at a comparatively low signal level (we denote this as "offset luminescence"). The fast recombination channels corresponding to ${\tau }_1$ and ${\tau }_2$ are responsible for $71\text{\%}$ of the total luminescence observed during test measurements. The luminescence associated with ${\tau }_1$ dominate the beginning of an experiment, but is depleted much quicker than the luminescence associated with ${\tau }_2$. We show that all recombination channels show similar response to preheating of the sample, which suggests that they are associated with the same trapping centers.