Evaluation of The Basic Dosimetric Properties of Calcium Sulfide Crystals With Rare Earth Elements As A Sensor of OSL Dosimeter

Today, OSL (Optically Stimulated Luminescence) dosimetry system based on optical stimulation, includes systems that can meet many requirements for radiation protection in the field of medicine and space. The Calcium Sulfide (CaS) is one of the earth's alkaline sulfide materials which can be used as a detector in this system. In this research, some of the dosimetry properties of CaS doped with Cerium, (Ce), and Samarium, (Sm) elements were investigated as OSL dosimeter sensor. First, attenuation of x-rays through the sensors were analyzed and the absorbed dose rate was evaluated using MCNP code. After calcium sulfide tablets were fabricated and their concentration optimized, the maximum waiting time prior to readout was obtained. In addition, the repeatability and linear response of the detector were determined as a function of CaS concentration. Eight minutes after radiation exposure of detectors, the detection output signals became stable. This stability was monitored for at least 30 minutes after irradiation. The repeatability in measurements was observed within the dose ranges of 100 to 860 mGy. The dosimeter response was observed linear over this dose ranges. According to the above-observed results and statistical evaluations, one can conclude that the CaS:Ce,Sm crystal is a proper sensor for OSL dosimeter systems in medicine and space studies.