OPTICAL AND DIELECTRIC-PROPERTIES OF NEUTRON-IRRADIATED MGAL2O4 SPINELS

The radiation effects on the optical and electrical properties of stoi chiometric MgAl2O4 spinel specimens irradiated in FFTF-MOTA at tempera tures between 385 and 750 degrees C to fluence ranging from 5.3 to 24. 9 x 10(26) n m(-2) (E > 0.1 MCV) are measured. In the optical properti es a strong absorption in the ultraviolet range is observed together w ith a small band around 20 000 cm(-1) (520 nm). Two strong luminescenc e emissions are also observed around 700 nm, with excitation spectra i n the ultraviolet region. In the electrical properties a strong decrea se of conductivity is observed in the temperature range from 0 to 500 degrees C. Other techniques (like dielectric spectroscopy and EPR) hav e been used.