Optimizing the size of cylindrical sucrose solid state/EPR dosimeters for high energy ionizing radiation

Electron paramagnetic resonance (EPR) spectroscopy has proved to be a very effective method of investigation of free radicals created in materials during irradiation with high energy radiation. In the years sucrose has been studied for a long time as a dosimeter in radiation accident and in high-dose dosimetry by using different analytical techniques. The sucrose is a tissues equivalent material and it is involved in the DNA structure. That is why it is important to study its radiation properties. In the last years sucrose was considered as one of the most promising radiation sensitive materials (RSM) for EPR dosimetry as an alternative material of alanine. It is know that there is a saturation of dose response of irradiated sucrose Solid State/Electron Paramagnetic Resonance (SS/EPR) dosimeters at doses higher than 10 kGy. One of the possibilities to dissolve this problem is adding of internal standard Mn²⁺ magnetically diluted in MgO to the RSM. However no many laboratories have such kind of standard and it is not easy to be prepared. Therefore the aim of the present work is to achieve a linear dose response of the cylindrical dosimeters at possible the widest interval of doses, only through change their diameter and height and without to use an internal standard. In view of this it has been researched cylindrical sucrose dosimeters with different sizes (diameters 2, 3 and 4 mm and heights 5, 10 and 14 mm). From the obtained results have been found that with decreased of the diameter of the dosimeters from 4 to 2 mm the intensity of the EPR signal became linearly depended from the absorbed dose radiation in the dose range 1-50 kGy. In the dosimeters with diameters 3 and 4 mm a weak saturation of the dose response curves at higher doses have been observed. This confirms our previous claim that the saturation is due to simultaneously impact of the deeper penetration of the samples in the electric field in the EPR cavity and of the irradiation with high dose gamma rays. The increased of the height of the dosimeters from 5 to 14 mm aims to increase the sensitivity and to some extent to compensate the loss of sensitivity due to the smaller diameter. Charcoal samples with the same shape for comparison have been prepared. (author)