| Abstract: | The noise properties of the granular phosphor screens, which are utilized in X-ray imaging detectors, are studied in terms of the quantum noise transfer function (QNTF). An analytical model, taking into account the effect of K-characteristic X-rays reabsorption within the phosphor material and the optical properties of the phosphor, was developed. The optical properties of the phosphor material required by the model were obtained from literature, except for the optical diffusion length (σ) that was determined by data fitting and was found to be 26 cm2/g. The deviation between theoretical and experimental data is σ depended. Specifically for σ=26 cm2/g and σ=25 cm2/g the respective deviations between experimental and predicted results were 0.698% and −1.597%. However for relative differences in σ more than 15% from the value 26 cm2/g, the corresponding deviations exceed by 6 times the value of 0.698%. The model was tested via comparison to experimental results obtained by a set of Y2O3:Eu3+ phosphor screens prepared by sedimentation. The model may be used to evaluate the effect of screen thickness and irradiation geometry on quantum noise of phosphor materials for transmission and reflection mode. |
