Study on photoluminescence properties of Er2O3 materials as irradiation damage and temperature sensors

Photoluminescence (PL) properties of Er2O3 specimens were examined by using visible lasers (532 nm and 635 nm) and a UV LED light source (365 nm) to investigate the applicability for irradiation damage monitoring of materials in fusion reactors. Both in the laser induced and UV light induced PL spectra, green (510–590 nm) and red (630–725 nm) luminescence was observed. In the spectrum measurements on specimens with different crystallinities, it was confirmed that an intensity of the red luminescence weakened significantly compared with that of the green luminescence in an Er2O3 specimen with a lower crystallinity. The results indicate that the PL measurements of Er2O3 materials could be applicable for the irradiation damage monitoring in fusion reactors. The luminescence property of ion beam irradiated Er2O3 showed that information of irradiation damages could be kept up to ∼ 300 ℃ and almost recovered at 700 ℃. Based on the obtained luminescence properties, positions in a fusion reactor where Er2O3 materials could be used as irradiation damage sensors are proposed. Changes in PL spectra at high temperatures up to ∼ 400 ℃ indicate the possibility that the Er2O3 materials might be applicable also for temperature monitoring of in-vessel components during reactor maintenance periods.