α-Al_2O_3:Mn单晶的三维热释发光谱研究

Study on 3D thermoluminescence spectra in sapphire:Mn

测量了α Al2 O3:Mn单晶中子辐照前后的三维热释发光谱 .观察到α Al2 O3:Mn单晶γ射线照射后测量的三维热释发光谱中 ,峰温在 35 0℃波长为 6 80nm处有一宽发光峰 ,这可能与Mn2 + 离子有关 ;波长为 6 95nm峰温在 170℃和35 0℃的线状光谱 ,叠加在 6 80nm宽发光峰上 ,是Cr3+ 离子的发光谱线 ,其中可能有Mn4 + 离子的贡献 .与纯α Al2 O3单晶的热释发光谱相比 ,掺入Mn杂质后 ,γ射线照射的三维热释发光谱中完全地抑制了波长为 4 16nm的α Al2 O3的F心发光峰 .经 10 1 7cm- 2 中子注量辐照和退火后 ,γ射线照射后测量的三维热释发光谱中 ,在 15 0℃出现了波长为4 16和 6 95nm的发光峰 ,以及在 2 5 0℃波长为 6 80和 6 95nm的发光峰 ,其中 6 95nm新发光峰的强度略超过了中子辐照前α Al2 O3:Mn在 35 0℃波长为 6 95nm的发光峰 ,说明中子辐照产生了大量浅陷阱能级和F心 .然而 ,经 10 1 8cm- 2 中子注量辐照和退火后 ,γ射线照射后测量的三维热释发光谱中 ,出现了峰温 15 0℃ ,190℃和 2 5 0℃波长为 5 2 0nm的Mn2 + 离子发光峰 ,以及 30 0℃波长为 6 80和 6 95nm的Cr3+ (或Mn4 + )的发光峰 ,表明增高中子注量的辐照 ,产生了温度为 190℃ ,2 5 0℃和 30 0℃深陷阱能级和F心 ,并使Mn2 +

The 3D thermoluminescence(TL) spectra were used to study the defect structure and luminescence mechanism produced by neutron irradiation in sapphire:Mn. The TL spectra of sapphire:Mn irradiated with 1000 Gy 60Co γ-rays before neutron irradiation show a broad wavelength band around 680nm at about 350℃ which may be related to the Mn 2+ ions emission, and there is the 695 nm line spectrum which superposes to 680 nm broad band that is emitted from Cr 3+ ions. Comparison between the spectra of undoped α-Al 2O 3 crystal and that of sapphire:Mn shows that the emission spectra of undoped α-Al 2O 3 at 416nm at about 207℃ related to the relaxation of an electron from the excited 3P state to the ground state 1S of the F center, is seriously suppressed. After neutron irradiation with fluence 10 17cm -2, new glow peaks occur at about 150℃,at wavelengths 416 nm, 680 nm and 695 nm. The intensity of the glow peak at 150℃, 695 nm is greatly enhanced compared to that before neutron irradiation. The glow peaks at wavelength 520 nm at about 150℃, 190℃ and 250℃ emitted probably from Mn 2+ ions are observed after 10 18cm -2 fluence neutron irradiation. This indicates that neutron irradiation produces a quite amount shallow traps and F centers, and that 3D spectra are useful for studying the trap structures and luminescence mechanism.