Investigation of TLD Phosphors by Optical Excitation –Luminescence of Eu2+ Centers in MgSO4, CaSO4, SrSO4, BaSO4–

Abstract

The photoluminescence (PL) and excitation spectra of various thermoluminescence dosimetry (TLD) phosphors were measured at temperatures of 6, 17, 80 and 300 K. Their PL spectra at 300 K consist of a single band in the vicinity of 380 nm. The emission bands and their excitation bands are ascribed to the electronic 4f6 ·5d ↔4f7 transitions in the Eu2+ ions. In the PL spectra of MgSO4:Eu2+, SrSO4:Eu2+ and BaSO4:Eu2+, the emission lines due to the electronic 4f7 →4f7 transition in the Eu2+ ion were also observed near 360 nm, in addition to the broad band. No line emission due to the Eu3+ center was observed in any of the phosphors prepared in the present work. In CaSO4:Eu2+ cooled to low temperatures, phonon structures are observed on the emission band and the low-energy excitation band. The TL emission spectra of BaSO4:Eu2+ at various temperatures were also measured.