محسن محرابی

Doped Lithium tetraborate nano powders with copper (sample 1) and co-doped with copper-manganese (sample 2) impurities were synthesized via the combustion process and were used to investigate the optical properties. Scanning electron microscopic images plus X-ray diffraction patterns confirm the morphology, size and crystal structure of the produced nanoparticles. Using the Williamson-Hall plot, the average crystallite size was estimated at ~51 nm. From the absorption spectrum, the direct optical bandgaps obtained 3.68 eV and 3.72 eV for the samples 1 and 2, respectively. Besides, the thermoluminescence properties of nanoparticles irradiated with different doses of gamma-rays were investigated at room temperature. The results show that, adding manganese impurities to sample 1 significantly affects its thermoluminescence properties and improves them, so sample 2 is four times more sensitive than sample 1 relative to the gamma-ray. The dose-response of sample 2 is linear in a broader range of gamma-ray doses than that of sample 1 and its fading in one month is about half of the sample1.