Fig. 1. (a) Schematic diagram of the proposed X-ray detection set-up. (b) Microscopic image of the fiber head covered by PQDs embedded glass powders (left) and scanning electron microscope image of the glass powders (right).

Fig. 2. (a) PL and PLE spectra of PQDs embedded glass powders. (b) PL decay curve and the fit to the data. (c) Variation of emission spectra and intensity under water boiling treatment repeated six times. Inset: glass powders in a boiling water bath. (d) Variation of emission spectra and intensity under heating (up to 300^oC)–cooling (down to room temperature) treatment repeated six times.

Fig. 3. (a) X-ray excited RL spectra of the PQDs activated silica fiber (blue curve) and the un-coated fiber (red curve). Inset: schematic diagram of the fiber sensor. (b) Relationship between the integrated RL intensity and the X-ray dose. Solid line is the linear fit to the data. (c) Variation of the RL intensity as a function of displacement across the X-ray beams. Red line is the Gaussian fit to the data. Inset: an X-ray sensitive glass used to record the X-ray beam spot. The background is the image of an enlarged spot after X-ray irradiation. (d) Changes in the RL spectra and integrated intensity with X-ray exposure time.