Spectral comparison of MgSO4 doped with Dy, Mn, P, and Cu

Phosphor emission spectra are presented for MgSO4 doped with Dy, MgSO4 co-d oped with Dy and Mn, MgSO4 co-doped with Dy and P, and MgSO4 co-doped with Dy, P and Cu. All spectral wavelengths are related to transitions in Dy3+ i ons. In a broad wavelength band around similar to 660 nm, three dimensional glow curves at similar to 140 and similar to 190 degreesC in the MgSO4:Mn spectrum are due to emissions from Mn2+ ions. For MgSO4 co-doped with Dy an d Mn the main glow peak occurs at similar to 380 degreesC, about 20 degrees C above the fourth glow peak obtained in MgSO4 doped with Dy. The emission spectra of the MgSO4:Dy, Mn phosphor show the competitive de-excitation pro cesses between Dy3+ and Mn2+ ions. This indicates that rare earth and Mn io ns in MgSO4:Dy, Mn form complex defects that dominate the traps and recombi nations. The MgSO4:Dy glow peak at around 260 degreesC shifts in MgSO4:Dy, P to similar to 280 degreesC with enhanced intensity, while the similar to 360 degreesC glow peak remains in place with a slightly increased intensity . The enhanced thermoluminescence (TL) sensitivity obtained by co-doping wi th P is probably due to charge compensation. The relative intensities vary between the 480 and 580 nm band of the glow peaks while the temperature '(s imilar to 280 degreesC) is unchanged for MgSO4 co-doped with Dy, P and Cu. The Cu+2 or Cu+1 ions act as charge compensators to the Dy3+ ions and reduc e the concentration of Mg2+ vacancies in MgSO4:Dy, P, Cu. This results in c hanges to the dose response characteristics.