Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10731418 | Radiation Measurements | 2005 | 7 Pages |
Abstract
Electron paramagnetic resonance (EPR), thermally stimulated luminescence (TSL), photoacoustic spectrometric (PAS) and fluorescence studies were conducted on gamma-irradiated MgB4O7: Tm phosphor. EPR spectra of irradiated samples revealed the formation of BO32-, a hole-trapped radical at room temperature. The principal values for the g and A tensors are gâ¥â2.0071, gâ¥=2.0131 and Aâ¥â14G, Aâ¥=7G, respectively. In addition to this, the radical without any hyperfine structure was identified as O2-(gâ¥=2.0385 and gâ¥=2.0023). TSL studies showed the presence of an intense glow peak around 470 K and a weak shoulder at 550 K. Temperature dependence studies of the EPR signals in the range 300-600 K showed the thermal destruction of BO32- radical around 470 K. The observed TSL emission is caused by the recombination of thermally released holes from BO32- radical with Tm2+ ion. The energy released in the electron-hole recombination process is used for the excitation of Tm3+ resulting in a prominent glow 470 K. TSL emission studies confirmed that Tm3+ acts as luminescent center for the prominent peak at 470 K. The trap depth for this peak has been determined to be 0.975±0.03eV from both TSL and EPR methods.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Radiation
Authors
N.K. Porwal, R.M. Kadam, T.K. Seshagiri, V. Natarajan, A.R. Dhobale, A.G. Page,