Abstarct: Everyday advances in nuclear technology and the special application of radiation and the phenomenon of thermodynamics in dosimetry have led to the development of new and inexpensive TLD materials (thermometers) with high sensitivity to ionizing radiation. There are many substances in nature that have the property of exposure to heat. Calcium fluoride is one of these substances. In this study, calcium fluoride powder prepared from Merck Company using molds and presses of Mashhad University of Medical Sciences in the form of tablets with dimensions of .6,8 and 10 mm with thicknesses of and 1.5 mm was made. To strengthen the tablets, we raised their temperature by 5 ℃/min from ambient temperature to 100 ℃. It was then kept at 100 ℃ for 4 hours and then reached the temperature of 400 ℃ at the same rate as before and kept at a constant temperature of 400 ℃ for one hour. After making the tablets and strengthening them to measure the sensitivity, it was sent to Sina Partoo Jam Company and all the tablets were exposed to the standard 10 mSv radiation with 137 cesium source. After irradiation, the total load collected at the PMT output (in nc) was measured by placing the tablets in a TLD reader. Then, using the obtained data, the sensitivity coefficient and calibration coefficient were calculated for different tablets with the above dimensions.