Cooled optically stimulated luminescence (COSL) in CaF2:Mn is an ionizing radiation dosimetry method recently developed at Pacific Northwest Laboratory (1,2,3,4). The new method is thought to be an example of a highly sensitive phototransfer technique that could form the basis for future radiation dosimetry applications.Measurements to date have shown high potential for measuring gamma exposures as low as 10 μR. Along with the potential for a system that is more sensitive than thermoluminescent (TL) dosimetry, multiple COSL readouts may be possible with minimal reduction of the COSL intensity. The multiple readout capability can serve as a possible permanent dosimetry record, thus allowing a questionable reading to be re-analyzed.A new readout system is being developed in an attempt to optimize the sensitivity and to improve the reproducibility of the COSL method. This paper presents details of the new readout system, the COSL process, and recent data obtained with an older manual system.