Preparation and characterization of CaF2: Mn phosphor for high dose dosimetry

CaF2: Mn phosphor is known for its high thermoluminescent sensitivity and dose linearity up to few kGy. In the present study CaF2 phosphor with different concentration of Mn dopant was prepared and its further characterization was carried out through different techniques. The phosphor was prepared through chemical root using CaCO3, HF acid and MnCl2 as raw materials following precipitation method. TL sensitivity of this phosphor was compared with other well established phosphors used for radiation dosimetry. It was found that the TL sensitivity is about twice that of LiF: Mg, Ti, TLD-100 phosphor. However the sensitivity is half to that of imported CaF2:Mn. X-ray diffraction studies revealed that the crystal prepared is CaF2. TL emission spectrum showed a peak at around 500 nm which confirms the characteristic emission of Mn. ESR of the phosphor was also done and was found that it is dominated by peaks corresponding to Mn which are in a group of six and the g value calculated to be 2.006. The dose linearity in the high dose range from 50 Gy to 3 kGy showed that the TL response is linear up to 3 kGy within an uncertainty of 10-15 %. In view of its linearity in the high dose range it will be very useful for the dosimetry of commercial irradiator used for food and grains irradiation and also for other application using industrial electron accelerator where routine dosimetry can be done using this system and can be established. (author)