Permeation and optical properties of YAG:Er³⁺ fiber membrane scintillators prepared by novel sol–gel/electrospinning method

An electrospinning method for fabrication of the YAG:Er³⁺ fibrous membrane is developed and the scintillation properties of the obtained membranes were examined. A homogeneous precursor YAG sol was synthesized allowing to control the sol–gel transition. The synthesized precursor allows one to achieve the 5 wt.% level of fiber doping with Er without formation of any undesired crystalline phases. It was found that the relative humidity had a strong impact on the fiber microstructure. The fibers obtained at the low relative humidity level (~30%) had almost straight cylindrical shape with an average diameter of ~590 nm, their surface was smooth. The shape of fibers obtained at the high relative humidity level (~50%) deviated from the straight cylindrical shape and the average diameter was larger, ~1.12 µm. The fluid permeability of membranes, K, obtained at the low relative humidity level was measured using an upward wicking experiment to give K~10⁻¹³ m². The YAG:Er membrane presented a strong green photoluminescence under ultraviolet excitation and intense radioluminescence dominated by emission lines at 398 and 467 nm under the X-ray excitation. The properties of these materials make them promising candidates as porous scintillators for the detection of ionizing radiation of flowing fluids.