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

Abstract

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 τ1=22.8(1.7)μs and τ2=60(5)μs 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 τ1 and τ2 are responsible for 71% of the total luminescence observed during test measurements. The luminescence associated with τ1 dominate the beginning of an experiment, but is depleted much quicker than the luminescence associated with τ2. 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.