Optically Stimulated Luminescence in an Imaging Plate Using BaFI:Eu

Abstract

BaFI:Eu phosphors are fabricated using a new method of synthesis: liquid phase synthesis, in which the phosphor particles are formed through the association of Ba2+ ions, F-ions and Eu2+ ions in solution. An intense optically stimulated luminescence (OSL) peak at about 410 nm is observed by stimulating X ray irradiated BaFI:Eu phosphor with about 550-750 nm light. It is found that the peak wavelength of the optically stimulation spectrum is about 690 nm. This result suggests that the semiconductor laser can be used as the stimulating light source. It is also found that the OSL intensity is increased with increasing the X ray dose. The BaFI:Eu phosphor as a photostimulable material for the imaging plate of a computed radiography system provides the following advantages; (1) high X ray absorption coefficient, (2) high monodispersion in size which would contribute to sharp images, (3) high OSL and thus low luminescence mottle and (4) high DQE (detective quantum efficiency).

On some fundamental features of optically stimulated luminescence measurements

“…The peak shifts to lower energies for increasing S, Zu, f and T. The larger value of energy increase rate, a, similarly like the heating rate in the TL process, causes the peak shift into higher energies. It is interesting to notice that similar effects were observed previously even when the energy scan for the measurement of the OSL stimulation spectrum was carried out from the higher energies to lower ones (Nanto et al, 2002). The changes of excitation time (initial trap occupation) do not result in the peak shift in the case presented in Fig.…”

“…The luminescence intensity is proportional to the number of trapped electrons and this, in turn, depends on the dose of radiation used for transferring the carriers into trap levels. This relation between radiation dose absorbed by a phosphor and the OSL intensity is extensively used for dosimetry (McKeever et al, 2004;Gaza et al, 2005) or radiological imaging (Nanto et al, 2002;Schweizer et al, 2004;Selling et al, 2005). In the basic measurement of OSL, optical stimulation is carried out with light of constant wavelength and constant intensity (CW-OSL).…”

Storage Phosphors for Medical Imaging

“…This is exactly what has been proposed by Nakano et al . [27,28]. Replacement of Br − by I − leads to a higher crystal density.…”

“…Stimulation spectra of BaFBr 0.85 I 0.15 :Eu 2+ (blue), BaFI:Eu 2+ (black) (data from [27]) and BaFBr:Eu 2+ (red).…”

Optically stimulated luminescence properties of Tl-doped NH4Cl transparent ceramics fabricated by SPS method

“…In contrast, when the stimulation is heated, the luminescence is called thermally stimulated luminescence (TSL) [13,14]. Owing to the advantage that users can read out the luminescence signals at any time, storage phosphors are often used for personal dosimeters and imaging plates [15][16][17][18][19]. When used as personal dosimeters, storage phosphors ideally require the following properties.…”