Two-Photon Optical Stimulation for Readout of Radiation Detectors

Based on an analysis of published data, we formulate an idea that a cascade two-photon transfer of holes from traps to recombination centers occurs in borate phosphors used in dosimetry. The previously described kinetic model is supplemented with the absorption of a second photon by a hole in a metastable state. It is concluded that the intensity of the stimulating light flux should be accurately stabilized if readout occurs in the two-photon regime, since in this case the maximum amplitude of the optically stimulated glow curve has a complex dependence on the intensity of the light flux.